Outlaw for HT, Tubes for 2-channel?

I'm about to split my system into parts.

For HT I have a 1050 with Klipsch Cornwalls and Heresys...I love it!

For music I'm trying to make improvements. I have a restored Dynaco ST70 and I'm thinking of buying a tube preamp and adding the Van Alstine mod....or maybe go off the deep end and go SET.

It would be much easier to simply buy a 950/770 (or stack of 200's) and phono stage for both HT & 2-channel. Since I'm not putting my two systems in different rooms with different speakers, I was planning to run two pair of cables to each front speaker and switch when I wanted to have the tube 2-channel sound. For casual music I could simply play DVDs on my Outlaw 1050 HT system.

Am I creating unnecessary complication?

My effecient Klipsch Heritage speakers allow for low power tube options and are a bit harsh at higher volume on the Outlaw SS.

It's well documented in these forums how much I _hate_ tubes

I would try to use the ST-70 for your front mains regardless of if you're doing HT or plain stereo. You can probably get away with it fine with your efficient speakers. Might give it a try. I wouldn't feel like you need to spend a furtune on a tube preamp. The power amps alone may give all the magic you need

I have a 60 watt amp that drives my woofers (15") and a SET with ••GASP•• 5 watts (yes, FIVE) that drives my high frequency horns. I wouldn't recommend a five watt amp for your woofers (though the time I tried it, I was pleasantly surprised) but with sensitivity of 106db/watt for the HF horns, I doubt that I'm even cracking _one_ of those mighty five watts.

I bet your ST-70 will do fine: you might even try it un-modded. It's no slouch in stock form.

[This message has been edited by soundhound (edited January 20, 2003).]

I'm trying the ST70 with my Outlaw this week...I added a new quad of tubes, upgraded signal caps, and a few other minor tweaks.

Some have suggested that using the SS Outlaw for a pre is somewhat defeating the purpose and that I need a $500 tube pre for maximum benefit. I'm starting with the Outalw/ST70 and then I'll test a tube pre later.

I'd like to hear SET for 2-channel. Many just love it with 106db/w @1m horns saying it's the first watt that matters.

I have a tube preamp (a custom design) that I can switch directly from the 950 using their DACs or directly from my DVD player (Sony DVP-S7000). I can't tell a lot of difference between having the 950 in the loop or directly from the player. YMMV. Now a CD player with a tube output would be another story!

I was actually able to get _very_ decent levels from my 5 watt SET having it drive some medium efficiency JBL monitors (4412). It sounded glorious, but the bass was, as you would expect a bit 'euphonic'. I bought the SET for my HF horns anyway, and it works wonders in that application, 1,200Hz and above.

You could also go crazy and get a SET with up to around 30-50 watts to drive your mains. There's a few that use that Russian monster triode. Big bucks, big heat, big glow from the filaments, big smile on your face...empty wallet....


I bet some of the other Outlaws think we've gone plum loco, talk'in about five measly watts. Pass the spitoon

[This message has been edited by soundhound (edited January 20, 2003).]

Hoots, SH put a bug in my ear, and for a $100-150 "intro" to tubes, I'm going to try one of these:

http://www.behringer.com/02_products/prodindex.cfm?id=T1951&lang=eng

I get to keep all my ss stuff, and just see what the effect of tubes would be. ("Poor man's" version.)

And, I get a parametric eq for my mains. (I have a pro Symetrix 552E I've never had a chance to install in my system. Taming room nodes and stuff, not trying to make a perfectly flat response or anything.)

The funny thing? Behringer (to me) is most well known for their DSP1124 Feedback Destroyer, which is a digital parametric eq useful for eq'ing subs. But the T1951? All analog baby!

Kevin:

Let us know how it works out

We'll know when you've gone into the terminal phase of the tube disease: you'll start talking about single ended triodes


BTW: How do you like the 'industrial - retro" look of the EQ? That look is really strong in studio stuff now: I like it. Would you buy a 950 if it had that kind of styling?


[This message has been edited by soundhound (edited January 21, 2003).]

I do exactly what you are looking to do. I swap my speaker cables out when switching between my tube based two channel rig and my HT system. It isn't too much of a burden for me. I don't want to waste my tubes on football games and movies. We all know they ain't cheap.
Greg

I'll let ya know! I'm kind of looking forward to people asking me about those "glowing things" ...

I guess that all depends on who's winning the game at the moment

Someday I would like to hear the Klipschorns with SET. It seems to be very popular with the KHorn crowd.

I'm starting with the Dynaco ST70 (done) and currently shopping for a tube pre-amp. I'll then do the Curcio mod on the ST-70 if I like the results and don't mind switching back and forth between HT & 2-channel. My kids play PS2 on the Outlaw system, we both watch movies on the Outlaw system, but I want to listen to the best 2-channel I can get which is leading me down the tube path.

I've been curious....if I upgrade from the 1050 to a 950 with an Outlaw SS amp, what type of improvement should I expect with my Cornwalls & Heresys 6.1 system? I'm pretty happy w/the 1050.

You know, every time I have powered a very high efficiency speaker with a relatively high power amp, my reaction has always been "YUCK". These speakers just sound better with an amp that is putting out a higher percentage of it's total power, rather than just idling along near it's noise and 'grundge' floor. I think the lower power of the 1050 amp might sound better than a much higher power one. If you need the features and sound processing modes of the 950, you might try to find a lower power amp, SS or tube to use with it. I bet you'd be happier with the sound.

As Paul Klipsch was fond of saying: "What the world needs is a good 10 watt amplifier!"

An analogy I just thought of with SH's comment: I work in the semiconductor industry, but that doesn't even matter. We have these high tech tools that do etching, deposition, rapid thermal processing, etc, of wafers. One of the "rules of thumb" you learn, is that equip is much more comfortable running in the 15% to 85% range of any particular setting (gas flow, power, pressure, etc.). Less than 10% or more than 90% is asking for trouble. I never even thought of that for power amps in a home theater!

I guess that rule of thumb is applicable to a lot of things: my motorcycle is a lot happier running near the upper 15% of the speedometer's range

That's one reason I wouldn't consider using anything more than my 5 watt amp for the HF horns. I'm actually considering trying an alternate tube in the output (2A3 vs 300B) which will lower the power to about 2.5 watts, but will put the amp even more into the meat of it's range at normal to loud listening levels.

[This message has been edited by soundhound (edited January 22, 2003).]

my motorcycle is a lot happier running near the upper 15% of the speedometer's range

Yes but just think of that poor officer who has to run in Kevin's "more than 90%" range just to say hello to you.

It's a Harley so it's probably still under the limit.....

[kidding, kidding....]

A Harley will blow a head gasket and start leaking mass quantities of oil before the engine goes that fast: they call it a "rev limiter"


BTW: I have a Kawasaki and a Suzuki

For some reason I thought you were a Harley guy - probably the Mac & Tube stuff got me confused. I'm not anti-Harley, I recognize their place as an American Icon and respect what they do, I just don't see them as purveyors of high quality machinery (like these guys http://www.titanmotorcycles.com/showroom/ ) or certainly not high performance machinery, although they're trying to do something about that I guess.

I got rid of my street machines, hanging onto the dirt toys a while yet. What bikes do you ride?

Charlie:

I wouldn't touch a Harley - they seem to me like a Rolex watch that can't keep time worth a damn. Besides, Macintoshes (especially using UNIX-based OS X) and tubes perform!

My bikes are:

Kawasaki Nomad (heavily modified)

and

Suzuki V-Strom


[This message has been edited by soundhound (edited January 23, 2003).]

“You know, every time I have powered a very high efficiency speaker with a relatively high power amp, my reaction has always been "YUCK". These speakers just sound better with an amp that is putting out a higher percentage of it's total power, rather than just idling along near it's noise and 'grundge' floor.”

You learn something new here every day!….More please Soundhound (if you have time and are in the mood) …although I can vaguely grasp the theory or commonsense behind this…(that it’s a very valid effect).

I’m very curious…and how do I put pen to paper to figure out power needed for channels run (2 Vs 7) so if I can expect a possible short draw out to all at any given time depending on source, including speaker eff. Etc. And be sure of enough to handle the hard hitting and sometimes loud transients of HT action DVD’s etc. which can hit all speakers at once occasionally on DTS ES discrete etc.

I was just swinging so firmly to ‘more power’ in fact was placing myself in the mentality that lots of excess power ideling(in reserve) was a good thing. . Because of some real world differences I heard in demo’s of speakers which had pretty good amperage (or well known amperage) but did not sound like the ‘most’ was being got out of them, in fact they felt anemic and power starved….
These were specifically Sonis Fabers, Martin Logans, Vienna Acoustics, and a few others with B&K separates and top of the line Pioneer receiver

Let me restate…your sentence has the ring of ‘validity’ to me but I’ve never run into (the thought) before. How do I cut the mustard? (never clip and stay out of running on average play in grunge range??)

PS. Nice bikes! I went to visit the distant relatives in very tiny town in Missippi many years ago with my Grandmother. Only time I had non-parental acess (mine forbid "riding on those things!"). I chased a cousin into some farm field at full throttle and suddenly discovered I was in 4 feet of nettles (I was bleeding ouch!) ...trying to get back out at practicly idle with shorts on!. But sans nettles it was a great time having access to those for the only time in my life!

[This message has been edited by Smart Little Lena (edited January 24, 2003).]

Not sure how good your grasp of this is, so if you already know this don't think I'm trying to send you back to pre-school or anything.

Anyway, db's are kinda crazy things, and at 106 db/1 w 'hounds speakers are roughly 40 - 50 times more efficient than 'average' speakers. So when he has 10+ watts driving them, well, he's still got lots of poop in that system where it matters, at the human ear.

Very roughly, every:

10 db, x10
5 db, x3
3 db, x2

pre-school or anything.
I am! - I’m a perennial student and am a card-carrying member for life!

You’re right as far as SH talking about his speaker’s HIGH sensitivity. I do recall the almost double the power rule of thumb for 3db more @ etc. (Not watching my details on this but you get my drift).

What he caused me to contemplate is (since I hate math really a bother trying to deal with the science behind much in AV) It ‘sounds right’ to me that drawing from a amp near its idle point could create ‘grunge’. Don’t grasp the ‘why’ behind it…just makes sense. (Guess I’m digging for the why explanation behind this also…why does running at low-draw on high-current interject more noise).

So allowing for that how do you match power to your sensitivity level (speakers specs) and in a split HT/music system where you have 7 installed and the potential for a large request of power for short transients set up the system so that your not running the high-current large reserves of power at idle all the time for the majority of your listening (interjecting ‘grunge’ on your average listening). Yet protect your system from being underpowered lowering the clip threshold dangerously low? I can see if your goal is to run your amp near say 80% draw most of the time …where this would be much easier to figure out for a 2-channel system.

I assumed that often systems are set up for 2-channel with mono-blocks etc with a 5-channel added later due to the way consumers purchase….their separate system is begun with a 2-channel amp so they just purchase minimum required channels as they add speakers for a Surround setup. SH’s statement sends me to think if you expect less draw out 2-channel and try to more closely match your power range to the front channels. (so that your not running in grunge range when listening to 2-channel) and place a 5-channel on the rest with larger reserves for the sometimes more demanding draw of HT. That’s a plus for using a multi-amp configuration Vs the convenience of running one 7-channel .
Although I see many 2-channel guys putting some hefty power on the fronts so that adding a multi-channel setup will not draw too much away from these if they don’t keep the systems separate.

I’m trying to match my recent formed conclusions regarding power (you can’t have too much - and underpowered is always more dangerous than overpowered for speaker life) and my recent listening experiences when I ran into mediocre sound more often when the amps run were barely adequate to the system. – and include SH's intriguing comment about not interjecting grunge by having amplification that is (on average) running at a low percent draw rarely tapping huge reserves.

Lena:

The effect I was talking about is really about the efficiency of the speaker verses the power output of an amplifier. Picture if you will an amplifier that is putting out a constant level of hiss. Place speaker "A" on it with an efficiency of 86db/w, typical of a speaker with low to medium efficiency. Lets say that, just for sake of comparason it produces, with your ear next to the tweeter, 50db SPL of hiss. Now place speaker "B" on the same amplifier, not changing anything else except that speaker "B" has an efficiency of 96db/w, which is not unheard of in HT speakers. If you were to put your ear to the tweeter as before, the noise would measure 60db SPL : a 10 db increase, or subjectively twice the level of hiss. Now hang an efficient horn speaker on this amplifier with a sensitivity of 106db/w, as mine are. The hiss you would measure would be 70db SPL - twice again as much!.

Now, every solid state amplifier creates a certain amount of electronic noise (hiss), distortion, and other undesirable artifacts such as crossover distortion. These are usually a small percentage of their total power output . Some of these get worse as the power is increased (distortion), some are worse at the very lowest levels of an amplifier's output. Crossover distortion and hiss are the ones that are worst at the lowest levels.

We don't want an amplifier to operate near either of those extremes: full power and beyond with it's increased distortion, and clipping of it's output, and at the lowest end, with it's noise and crossover distortion. Generally, we want the amplifier to operate most of the time somewhere in the middle, well away from the detrimental effects at either extreme. It's that lowest end of the amplifier's output that I am concerned with here.

Now, power the speakers in the first paragraph with a 200 watt amplifier. Which speaker do you think will be using the least of this power? If you chose the 106db/w one, you were right. If you put that 200 watt amplifier on the 106db/w horn speaker, the amplifier would be asked to deliver a tiny fraction of it's available power almost all the time. In other words, the amplifier would be operating at at the lowest extreme of the power amplifier's output where the noise and crossover distortion is at it's worst.


Now, if you put a 50 watt amplifier on that horn speaker with it's 106db/w efficiency, you would see that relatively speaking, more of that 50 watt amplifier's power is used. In other words, the amplifier is operating more in the middle area of the amplifiers total output. It is farther away from the lowest extreme where the noise and crossover distortion is at it's worst. And since the speaker is very efficient, it is way less likely to need the full power output of the 50 watt amplifier.

Now if you put the 86db/w speaker on the 200 watt amplifier, you can see that more power would be asked of the amplifier most of the time and as a result, it would be operating more in the middle area of the amplifier's total output. And since the speaker is less efficient, it would be more likely to need 200 watts in order to avoid clipping. If you used the 50 watt amplifier with this speaker, you would likely run into clipping.

In the days of 2 channel (back when dinosaurs roamed the land, and soundhound was a young lad with a cow lick in his hair) almost all speakers were of low efficiency. Those speakers required amplifiers with large amounts of output power in order to drive them effectively, so that the amplifier would not clip when relatively high sound pressure levels were asked for (like when cranking Led Zeppelin ) In those days, a big amplifier was better than a small one.

But something happened during the morphing of 2 channel stereo into Home Theatre. It was found that speakers needed to have higher efficiency in order to deal with the loud explosions, gunfire, and car chases (and that's just in romantic movies - blockbusters are worse). It was also necessary to raise efficiency of the speakers so that multi-channel amplifiers could be built that had practical power outputs (a 7 X 1000 watt amplifier would be impractical!) However, the "bigger is better" mentality remained. To paraphraise Porgy and Bess: that ain't necessairly so.

Another consideration is that in a typical home theater setup, the really low bass is re-directed to the subwoofer. That low bass is where the amplifier is asked to deliver it's most power. If the amplifier is relieved of this requirement by bass management, then the amplifier is going to be working again nearer that lower end of it's power range, relatively speaking.

As you can see, it is not as simple as you would think. There are a lot of variables to take into consideration. Generally speaking, if you have speakers that are more in the typical range of efficiency, in the 80's to mid 90's, you really need a more powerful amplifier. If you have really efficient speakers, in the high 90's and above, I would look at what I've said here, and re-consider your power requirements.

I hope this explains the situation better!

[This message has been edited by soundhound (edited January 24, 2003).]

Or put in yet another way, if I have 105db/1w speakers and a 30 watt amp, and I listen at 85 db with 115 db peaks my amp will be running between about 0.01 watt average with short trips to 10 watts. Pretty reasonable range.

In a second case, where I mated a set of 90db/1w speakers with a 200 watt amp, listening at the same SPL, the amp would average around (a bit under) 0.5 watt with peaks about 300 watts, or deep into clipping.

So in the second case, 200 watts isn't as loud, or 'big enough', as the first case. This is where (IMO) the 'bigger is better' amp generalization comes from, because it's almost always true.

In short, one size doesn't fit all at all. The majority of speakers I personally know of that fit most needs run anywhere from 85-95 db/1watt, or at least 10x less sensitive that the ones 'hound uses. His system, although almost certainly excellent, is also atypical.

In the more typical range I'd use anywhere from 100-1000 watts, which not coincidentally is where many amps land powerwise. So I guess I'm saying IMO you've done fine so far.

Oh yeah, one more thing - speakers SAY their sensitivity is in db/watt, but in reality its almost always db/volts referenced to 2 x the square root of 2 volts (~2.83).

[This message has been edited by charlie (edited January 24, 2003).]

As an aside, and in the intrests of confusing the matter more, class "A" single-ended amplifiers (they can be tube or solid state) do not exhibt crossover distortion at all. There is no division of the 'positive' and 'negative' portions of the audio signal as in a class "A/B" push pull amplifier, it's one unbroken wave. There's no low level crossover distortion to be had, so this type of amplifier is especially useful for very high efficiency speakers such as mine. I use a class "A" single ended triode tube amplifier for my high frequency horns: it puts out only five (!) watts, but I would never even need that much power, given the efficiency of the horns.

Then there's class "A" push-pull amplifiers, but I'm not going to confuse matters too much

[This message has been edited by soundhound (edited January 24, 2003).]

SH, you are hereby nominated to author “AV Electronics for Dummies”
What a crystal explanation even for me on a first read. Betweens Charlie’s math and your explaination.
I have calmed down from a knee-jerk, What? more power isn't always better?

I do forget (early days yet) to think backwards from speaker sensitivity. And how incredible the difference is in 10 dB increments of these ratings when calculating power required. And then there’s impedance and as you point out …class of amp.
So at 91 dB 4 Ohms on FL/FR, and 91 6-Ohms center and 90dB on small satellite surrounds. 200watts per channel are not going to leave me ever hovering in grunge territory.

Also believe it or not (I don’t) I end up being quizzed by fellow shoppers when I’m out, (including a lot of men which I find incredible as I thought they were all born with AV knowledge) Asking me questions when a sales person has walked off after they hear me talking to sales. (I always preface my answers with …”I only know enough to be dangerous” and…”I really just have bits of this down, -Get some professional help!”) But I have talked to 2 guys already about what amps they’d want to look at while in stores thinking of beefing up their old receivers or looking into separates etc (Don’t want to steer anyone wrong…but I very clearly tell them I’m a neophyte)
Its too easy at my stage to spout genralalities without the slightest grasp of all variables involved and I try not to do it.

Thanks - I guess I'm just used to explaining things to my wife

A few comments, questions (and equations) about dB output, speaker efficiency, amp power, noise and that grungy noise floor...

For the purpose generating further discussion I submit the following:
As SoundHound has very aptly described, he has incredibly efficient speakers and as a result can use a less powerful amplifier to achieve reference level dB SPL's (volume). As opposed to more typical audio systems using less sensitive speakers, SoundHound also points out that efficient speakers produce the wide dynamic range for music and movies with a far smaller range of amplifier power (in direct terms). I believe it is also true, however, that no matter how efficient the speaker, there is a proportional relationship between power and sound level (dB's), which has some very important implications.

As we are concerned about amplifiers operating in the extreme lowest and highest power ranges where distortion becomes problematic, the goal of matching the amplifier design and the speaker is critically important. Furthermore, as the sensitivity of the speakers increase, it appears that the total system becomes more susceptible to noise generated by the other components, signal interference and the like. For those who can not customize the amplifier to these high sensitivity speakers, it seem like a very delicate and potentially expensive road.

Signal Level (dB @ 1m) as defined in my text as:
dBm = 10 x log (Amp Power in watts x (10 to the exponent (Speaker Sensitivity /10) ) )

Thus, speakers with a sensitivity of 106dB/watt, at one watt amplifier power, will produce a signal level of 106dB. Because of the high sensitivity, it would take only 0.000795 watts to produce a signal level of 75 dB. I am confident that SoundHound has the right amp for the job, but WOW, these are some really small amp power numbers. A signal level of 65 dB would require only 0.00008 watts of amp power... and so on... So, I am curious; where is the grunge floor on the tube amp that can make this system sound great when the music gets soft, and movie is at a whisper?

I have B&W N803 mains, with a sensitivity of 90dB/watt. These are bi-amped with two channels of a OA Model 770 dedicated to each main speaker. . According to the formula, it takes 0.032 watts to produce a signal level of 75 dB. Although this seems low, it is 40 times more power than SoundHounds speakers require for the same 75dB signal level. I have no idea where my grunge floor is, as I do not have the diagnostic equipment, or the expertise to find it on my own. All I know is that I love what I hear; when the music is as delicate as a Chopin nocturne, or when Jimmy Page tears up the Stairway to Heaven.

Speaker preferences are what they are, and all of us can enjoy our own, but I am very interested in how the gunslingers view the interrelationship between Speaker Sensitivity, Amp Power, Amp Type, Noise and the Grunge.




[This message has been edited by AGAssarsson (edited January 26, 2003).]

I think I described the situation pretty well in my long winded post, but I'll try to 'splain further.

First of all, this whole exchange came about because of a post by Hoots, who also has very efficient speakers. Not as efficient as mine, but more efficient than 'normal'. I gave him my recommendation that he keep his lower power amp to drive them, as it probably has enough power for the job.

The post was really directed at those crazies like me who have really sensitive speakers: then Smart Little Lena (bless her heart) picked up on the post and a thread-fest ensued. If you had ever seen my setup, you would know that it is not even remotely typical of what a sane person would do, but that's just me

So, the bottom line is that it simply does not applly to most of everybody else out there: they have components that are matched pretty well, not to worry!

Now to answer your question on how much "grunge" is too much, well, the short answer is that ANY solid state push-pull amplifier on speakers as sensitive as mine will sound really bad. It's that noticable. The "grundge" floor is not a "constant" that you can measure, as I was specifically seperating out crossover distortion as a main culprit. Not the only one, but the most significant one in this situation. This is a dynamic function, not a static one: it is essentially being modulated by the audio signal.

In a typical solid state amplifier, there is a standing bias current that is flowing through the output stage at all times. If the signal stays within this amount of current, the output stage is operating essentially class "A" push-pull. At the point where the signal JUST TRANSITIONS from class "A" to class "A/B", one transistor is cutting off, and another one is taking over in the push-pull output stage (the other transistor has been conducting since just before the 'zero' transition). This is where that crossover distortion "grundge" resides. This class "A" window is exceedingly narrow in a typical solid state amplifier. Unfortunately, this also occurs right at a point where the program material is soft, and the distortion is not swamped by the signal in speakers with sensitivities as high as mine.

The more bias current that flows, the broader this class "A" area is, before it transitions from the 'positive' set of output transistors to the 'negative' set of output transistors. The catch is that the more bias current that flows, the more static heat is generated. High end stereo solid state amps tend to have a very broad transitional area. Therefore, they have to have huge heatsinks to dissipate the heat, and this costs money.

Anyway, normally this not as bad as it sounds, since this form of distortion is reduced by the negative feedback that all such amplifiers have. With speakers such as mine, it can't be reduced enough to not to be audible.

I don't know if you caught it in a post I had later in this thread, but I get around the problem entirely with the use of a single-ended triode tube amplifier for my high frequency horns, 1,200Hz and above. A single ended amplifier has a single output device, and operates in pure class "A" all the time. The micro-transitional effects of crossover distortion are avoided simply because there is no transition from one device to another. One output tube: very simple and basic. There is also no global negative feedback. Therefore a lot of potential problems are just side steped by the use of this amp for high frequencies. For the woofer, I use a 50 watt traditional class "A/B" tube ampilifier. This tube amplifier, in common with all tube amps, has a very broad transitional area between the time it is operating in class "A" push-pull and when it goes into class "A/B". Since these woofers are quite sensitive, I am not usually getting out of this class "A" area under normal listening conditions. For those occasions when more power is required, the crossover distortion is way below the signal level.

I hope this gives you the information you need!

[This message has been edited by soundhound (edited January 26, 2003).]

I gave him my recommendation that he keep his lower power amp to drive them, as it probably has enough power for the job.

And that’s what startled me. Due to the first of the two guys I mentioned recently asking if I felt added amperage would make a difference (worth the expenditure) to a purchase of a HK8000 which is rated around 110 watts x 5 channels. He had mentioned his speakers sensitivity (maybe Polk at 89). And I had give him a hearty yes, that I thought he would benefit and that I would 'hear' a difference in that sort of setup from adding watts and using the HK as a pre. Same scenario with the second guy who was looking at receivers and asked what I thought about the advantages of separates.

Now I’m prob in no danger of being asked these type questions by guys who own anything with sensitivity above 98 (as you point out it’s rarer than not in most setups) not knowing enough to match his speakers to his amps. Unless he inherited some gear, or just purchased used from someone and has never been into AV before. But I know in those 2 recent moments my brain was not prioritizing, - figure back from the speaker sensitivity (first). I DON’T LIKE being asked (too much pressure) I like talking about AV but not giving someone advice who appears to know less than I without enough experience to take me seriously when I state I’m clear on this fact (ex: you HAVE to purchase a 2-channel amp to use the HK8 as a 7.1 setup regardless that the box states it’s a 7.1 receiver)…but check into the parameters of, -some other subject were discussing because I’m vague on details….as I mentioned I do state empathathicly when I get in these boats, I am new to this and have fringe knowledge in many areas…..but I hate to think if the guy just got his Dad’s old set of speakers @ 106! And never paid attention before, that I might have neglected to factor this spec! I wanted clarification on how to figure it for the variables in each system.
And now I see (better) why tube amplification (single stage) is not even just a ‘type sound’ preference in a system like yours its practically a necessity to reduce interjecting added distortion.

Bless her heart. (I almost heard a sigh in that one SH ).

You poor thing…. You probably come here to get away from … (if you have one like me), whom is always asking…”But WHY does it work that way?”…….and run into…( 20 questions - SLL)


[This message has been edited by Smart Little Lena (edited January 26, 2003).]

Well, you can look at it this way - if he inherits the speakers from his dad, his dad probably also had a good tube amplifier to go with them! Just tell him not to mess with those new fangled solid state thingamajigs

PS: I didn't get my 106db/w speakers from my dad, nor his Jackie Gleason LPs

[This message has been edited by soundhound (edited January 26, 2003).]

Dear SoundHound:

Your post was exactly on point. Actually, I have been following this topic forum with great interest, but I thought (with a little nudge) you could make a more clear case for the existence of tube amps so that us deputy's could get a handle on it. You did a great job.

There are many who believe that solid state amps are the logical choice for all. Most of my clients are of the misconception that 'solid state amplification' means digital signal throughout, and that 'tube amplification' equals more coloration and distortion. Some seem to have suggested these falsehoods in this thread as well.

As I believe you stated, the crossover distortion of a typical solid state amplifier at very low power levels is a dynamic condition that is not compatible with your speakers. A speaker with 106dB sensitivity will benefit from the design/performance characteristics of your tube amps. It is quite simply... amazing how small the power requirement is for moderate levels of volume (signal level) in your situation.

It seems to me that it must be a labor of love for you to make your speakers work as well as they do. This level of passion and expertise serves you well. For the rest of us who will never jump in the deep end of the pool; less sensitive speakers, and more powerful solid state amps like those made by Outlaw are probably the logical choice.

Thank you for your kind response.

Allan

I think yhis has been a great post and I think many (myself included) have been somewhat educated. I've been wondering while reading, is there a benefit to either high or low sensitivity speaker designs. What I was wondering (especially from soundhound) if today you went to purchase speakers and you had all of you technical knowledge but had never listened to any speakers what would be your criteria for evaluating speakers. I guess what I'm asking is do you love your tubes because you love the sound of the horn speakers and that is the best thing to drive them? Or do you like the sound of the tube amp and you need those horns to make the package work at it's best. Or do you just enjoy having a setup that you can tinker with? My guess is you've spent a fair amount of time getting your system to the point it's at now and I'm just curious of the road you traveled getting here.
I would also request opinions on sensitivity vs sound quality. Is there any correlation of the two or does a speaker just end up at a certain sensitivity based on it's design?

I've listened to high, mid and low efficiency systems that sounded great. Horns are waveguides, so they have unique sonic properties. Whether you like them or they work well in your room is a personal choice - listen (to good ones) and see. Horns are complex and easy to do badly, moreso than some other sorts of designs, so QoI is a great concern with them.

Also, in bass systems efficiency = size, (generally) so that is something to think about.

Horns used to be the only way to get any sound out of the feeble power amplifiers available in the 1920's. They were used in large spaces like movie theaters to make a few watts of power fill an auditorium. And, of course, they were used on acoustic phonographs to get any sound at all!

Is there an advantage in using them now? Well, let's see.

They are still used in movie theaters, stadiums, concert halls and any other place where the sound has to be very loud, and fill a large space. One of their chief advantages is that because of their sensitivity and efficiency, they can easily take the wide dynamic range of motion picture soundtracks, live music, etc. If you tried to push any all-direct radiator speaker to the sound presure levels encountered in filling a movie theater, it would self-distruct in no time. Also, horns can be made to any directional characteristic needed. They can be made to fill a very specific area of an auditorium, with no sound wasted from being directed where it's not needed.

None of the above advantages have anything per se to do with home theater, or sound quality in general. In fact, the above systems sound pretty darn bad by hi-fidelity standards!

Now, Paul Klipsch of Klipsch Loudspeaker fame recognized the advantages of horns for home use in the late 1940's and created the Klipschorn. He championed one unique advantage to horns that does have a direct bearing on sound quality. That is low amounts of doppler and harmonic distortion. Simply put, doppler distortion arises whenever the source of sound moves, relative to a fixed point (the listener in this instance). What is moving? Picture the cone of a 15" speaker moving back and forth by 1/2" as it reproduces a 30Hz tone at a loud volume. Now superimpose another tone of 1000Hz on top of that 30Hz tone. The speaker cone is now moving that 1000Hz tone nearer and farther from you at a rate of 30Hz! The effect is exactly as that of a car passing you by while honking it's horn. In that speaker, it will make the 1000Hz tone sound like it's 'underwater', or 'gurgly'. You are literally frequency modulating that 1000Hz tone, and creating distortion sidebands in the process.

Paul Klipsch reasoned that since a horn is very efficient, it's moving parts (the diaphram of the horn) needed to move very small distances in order to create healthy sound pressure levels. Because of this, his horn speakers produced dramatically reduced levels of doppler distortion (and also lower levels of harmonic distortion, for the same reason). They sounded cleaner than what was available at the time.

This is still true today, and is one of the chief advantages of horn speakers.

Of course, speaker technology has marched forward since that time, and today's speakers are much better than they were in 1950. BUT - take any speaker system today with direct radiators and play a loud continous bass tone that the speaker can reproduce, and add another pure tone that will be reproduced by that same driver (that has not been crossed over to the mid-range speaker by the crossover network), and you will hear doppler distortion if the level is increased enough.

Does this still matter today? People who make horn speakers (like Klipsch) think so.

When hi-fidelity meant only two speakers and music only, all this was somewhat a non issue to all but a few crazies like myself. Now, with the advent of home theater, with it's requirement to reproduce all manner of explosions, gunfire and other acts of violence, maybe it does matter. There's no denying that horns reproduce movie soundtracks with more 'punch' than direct radiators do. Those of you who have Klipsch speakers probably purchased them because they sounded good with movies. But does this make horns better?

That is a personal question. Any good speaker can sound wonderful. Speaker manufacturing technology has evolved tremendously, and today's consumer speakers sound WAY better than they did 20 years ago. But here are a couple points:

As discussed above, horns reduce forms of distortion like doppler, and also harmonic and intermodulation distortion because the moving parts have to move so little to create high sound pressure levels.

Because horns can have a very well defined directional pattern, they are very adaptable to the principles espoused by certification entities like THX. It is much harder to control directivity with direct radiators. The sound can be controlled and kept off walls, floors and ceilings to a greater extent before it reaches the listener. This has become important in home theater.

With a all-horn system (like mine) it is possible, by nature of the length of a horn, to achieve precise time alignment between the low and high frequency drivers by simply moving them in relation to each other, forward and back. Moving their relative position while looking at the reproduction of a square wave is a good way to achieve precise time alignment. This is not possible with direct radiator speakers, when the drivers are all mounted on one flat baffle. This limitation can be overcome however by slanting the baffle, or having stepped mounting surfaces for each driver.

Then, there is the characteristic 'horn sound'. This can be absolutely wonderful and 'alive' sounding if the horn system is executed well. Horns can also have a unique way of imaging the soundstage. They can image well behind the speakers (in stereo) as most conventional designs can, but they also have the ability to image the performers well into the room and all around you, way beyond the confines of the speakers. I've yet to hear a non-horn system that can do that as effectively.

Horns are unfortunately not executed well a good deal of the time, and the resulting horns sound simply "honky". Horn systems such as these, and horns used for PA applications have given them a bad reputation for some people.

And, as I have outlined in my previous posts, as horn coverage of the audio spectrum is widened, it becomes increasingly important to use tube amplification. This is because of the uniquely wide "class 'A' window" these amplifiers afford.

Horns are used mainly for tweeters in consumer systems today. It is very expensive to make a horn. In fact, most all horns today do not make use of a very important component that complements the horn: THE COMPRESSION DRIVER. Most horns today could be more accurately described as horn-loaded tweeters. They use a conventional speaker driver with a horn in front of it. A compression driver has a diaphram that fires through a 'donut' shaped magnetic structure. But before it reaches the throat of the driver, the sound passes through a 'phasing plug' which corrects the phase of the signals that enter the throat from the various parts of the diaphram. Thus there is no phase cancellation from say , the sound coming from the edge of the diaphram and that coming from the center. The problem with compression drivers is that they are extremely expensive to make. They require machining of precision parts, and this makes them cost prohibitive for consumer use.

The makers of today's horn speakers have done an excellent job of working around some problems arising from the lack of a true compression driver. Some of the phase problems resulting from direct loading of a conventional driver remain, however.

As home theater has come into being, there has been a gradual shift upwards in the sensitivity of speakers. This is probably for two reasons. More sensitive speakers (especially horns) are more able to take the abuse of sound effects that exist in modern motion picture soundtracks. This is simply because the speaker elements do not have to move as much to generate a particular sound pressure level. Thus less likelyhood of damage to the drivers. Another reason is that higher sensitivity speakers makes it possible to lower the power requirements of the power amps that power them. This was not much of an issue when amplifiers only had two channels, but gets to be a very big issue when as much as seven channels are put into a single amplifier chassis. 7 times 1000 watts? Get 'outta town!!

Would I purchase horns now, knowing what I do? You bet!

Should YOU? Well, that is a question only you can answer. Shop around and give the various horn designs a listen. There are only a couple firms that market all horn speaker systems currently, most systems having horn tweeters. Therefore, for better or worse, your selection, and therefore how crazy you can get with it, is somewhat limited. That is, unless you go with professional speakers....

[This message has been edited by soundhound (edited January 27, 2003).]

Keta:

My affair with tubes started when I was about 10 years old. I had a phonograph (one of those cheap things kids have). I used to play records on it all the time, and when the needle wore down, I just stacked pennies on the tone arm till the needle stayed in the groove. Then one Christmas my parents gave me a 'nicer' phonograph. I played it, but I still preferred the sound of my old phonograph. The new one just didn't sound 'right' to me.

A few years later I discovered why. The older phonograph had a vacuum tube amplifier, and the new phonograph had a solid state one!

As I grew older, I had a lot of amplifiers, tube and solid state. I always preferred the sound of the tube amps. They sounded more 'like music' to me.

I attended college, majoring in electronic engineering. After bumping around for awhile (never leave a 22 year old kid to his own devices) I started working for Altec Lansing, while they were still headquartered in California. There, I was exposed to the whole spectrum of sound equipment, from speakers to electronics, and such esoteric things as transformers and microphones. I got to see first hand the various technologies involved. My job was to design automated testing equipment for use on the production lines, so I had to learn the engineering principles behind all things audio.

It is here that I was exposed to horn speakers. I actually wound my own diaphrams for use in my horn speakers, and learned all the things that make a good verses bad horn. The horn speakers I bought while I was there I still have, and are now my main left and right front speakers in my home theater setup.

I found my horn speakers worked especially well for home theater because they were literally speakers intended for use in movie theaters! I did a great amount of modification and tweaking to them to tame some of their bad personality traits, and to make the most of their strengths. All these things I learned to do from the engineers at Altec Lansing.

It was about this time I also came to realize the symbiotic relationship of horn speakers and tube amplifiers.

Later, I was introduced to single-ended triode tube amplification. I found that this was an ideal solution for driving high frequency horn speakers because of the pure class "A" nature of their output stage.

So that is the story of my life with tubes and horn loudspeakers

I demoed some Klispch (Tweeter UE model ranges) and decided against them. I find your last couple of posts informative because I’m always looking for the ‘why’ behind why I prefer one thing (or don’t). Wishing to understand the reason particular products, possibly by their design, will have qualities I gravitate towards.
When I had a very short demo period and ended by choosing the Vienna’s much of the material I took with me were CD’s the only DVD I included was ‘Donnie Darko’ which at a certain dB level and in certain portions of the soundtrack is difficult for speakers tending to push them into distortion so I thought it would be a great test. It’s funny you mentioned some choose Klispch for its dynamics for HT. Although this area of capability was very important to me…with the guys here we spend many hours on blockbuster DVD’s. But I prioritized in my purchase that the speakers could handle music in a certain range and in a certain way that the Klispch fell short (for me), and I went with the Vienna’s. I felt the Vienna’s did not do (what they shine at), with busy HT type passages, - the Vienna’s are capable but not jaw-dropping for most HT, (although they have moments) dependent on Soundtrack. . I do not mean to state I feel they are incoherent or thin in detail or any characteristics as negative as that for HT, - but there is some ‘lack’ I sense that I can’t quite put my finger on. Maybe in part the “drivers on flat plane effect” (among other possibilities I’m trying to decipher) that you were detailing. Regardless, - several other speaker choices like the Martin Logans or Klipsch did not ‘move’ me with CD’s. I won’t give up listening to Electrostatics or horns or any other implementation whenever available to hear. But reading posts such as yours help me understand why sometimes I might lean this way or that.

SH and Charlie, this is one portion of why I enjoy the forum, for when those with particular expertise in certain passionate favorite topics let go a little of that info for fun. I’d say in virtual terms it’s the night break, - when the saddles are on the ground we’ve rolled up our interconnects, the moon is full and the cattle are quiet and we are all hanging around the
keeping good company.

Thanks for the share. (and the patience).


[This message has been edited by Smart Little Lena (edited January 27, 2003).]

Lena:

Your choice of speakers does not surprise me, given your emphasis on music reproduction. It is exactly that focus that is the biggest challenge for horn speakers. Of all the tweaking and fiddling I've done, by far the largest effort has been in making the reproduction of music as good as that of movie soundtracks (after all, movies are comprised of music too). It can be done.

I have succeeded in doing this, BUT it has involved a lot of work and sweat!

Would I recommend horns for people whose focus is music reproduction instead of films? NO WAY! Unless one is willing and able to do a lot of work, or finds a horn system that already sounds great to them for music, I would recommend a speaker system with direct radiators.

I would be interested in hearing the feedback of the other Outlaws out there that have horn systems like the Klipsch. How do they think they perform for music, verses movies?

[This message has been edited by soundhound (edited January 27, 2003).]

My personal system is to start at the ear (or eye) and work backwards, that way at least token examination is given to things like distance and room.

YMMV!

Here are a few more things to ponder.

Horns allow a greater mass of air to be coupled to a driver. For instance in the case of a 6" driver the mass of the air that is actually coupled to the driver is typically much less than the mass of the driver. This causes the driver to behave badly. A well done horn provides an 'impedance match' that allows the designer to couple more mass to the driver. There is a school of thought that states this is what a good horn should do.

There are other ways to control this 'behaving badly', but they all have trade-offs.

For instance a bass horn, well done, will be absolutely enormous due to the huge wavelengths involved. Most bass horns are somewhat compromised (undersized, folded, etc.) due to this sheer scale involved, although they often produce decent results.

And to really throw a curve, there are a lot of folks who like a design called a 'back loaded horn' where a horn is used instead of an enclosure to load the rear of a direct radiator (or front horn) system.

http://hornet.hi-fi.hr/HedStart.htm
http://www.vt52.com/diy/diypage/hedlund/hedlund.html
http://melhuish.org/audio/horn.htm

Charlie:

In the "Audio Anthology" reprints, there is an article about a man who built a straight bass horn where the mouth of the horn was one whole wall of his room, and the back of the horn extended into his yard!! Here is a picture of him standing next to his "creation". He said he did it all while his wife was away from the house visiting relatives. I'd love to have been a fly on the wall when his wife returned!!



[This message has been edited by soundhound (edited January 27, 2003).]

I suppose that would be, in most respects, the exact opposite of a Bose system?

Well, I guess you could build an entire wall of those silly little cubes and have, well, SOMETHING!

back to the original question...i'm an old guitar player and after years of searching for an amp that "sounded like me," I found an H&K with a tube pre-amp and solid state amp. I loved the pairing so much, I decided to recreate that setup in my audio system. When I finally saved up the bucks to plop down for a tube pre, I found an Anthem (model PRE-2L) with remote volume and a cool little button that puts it in bypass mode for HT applications. This allows you to set up your mains with a pair of monoblocks or a stereo amp backed by the Anthem and your choice of sources. I use cd and turntable (with an outboard phono pre-amp). When you want to watch a DVD (or listen to SACD or DVD-A if you have it), you hit the bypass button and your home theater processor/pre-amp (in my case, an Outlaw 1050)is able to play through the anthem to take advantage of the amp and mains used for 2-channel listening. This eliminates the need for extra speakers or cables or switching cables. The reason this was so appealing to me: I went for a budget system for movies (Toshiba DVD, Outlaw receiver, Energy Take-5 satellite surrounds and center) but I take my music very seriously. I listen to vinyl and cd on a Music Hall MMF-7 and Jolida JD-100 tube/hybrid cd player ,respectively, through the Anthem to a B&K Ref-2220 going to a pair of Quad 22L loudspeakers. The Anthem has allowed me to watch movies with the benefits of the B&K and the Quads, where before, I had two completely separate systems with nothing but satellites all around. The 1050 is a monster for the price and adequately drives the Quads; I have been thrilled with it, but it does not keep up with a 220 wpc reference series B&K for dynamics and clarity in 2-channel listening. This is why I have always had two systems (the two receivers I cycled through prior to finding the 1050 left an even bigger gap in performance). The warmth of the tubes is amazing for music and I will probably always have a tube pre-amp of some kind somewhere in my listening arsenal. I am thinking of upgrading my 1050 for a 950 to get the extra processing formats and other upgrades (I have six Marantz MA700 monoblocks just sitting there burning a hole through their boxes)but I will still use the tube pre-amp for music. There are other tube pre-amps that function like the PRE-2L but they were much more expensive to start with and I got a deal on the PRE-2L anyway (retail $1300, I paid $900 NIB). I have seen some PRE-2Ls on E-bay and Audiogon and saw one on consignment recently at Atlanta Audio in Marietta, GA. It is recently out of production but you may find a new one at an Anthem dealer (that's where I got mine). The fun never ends; good luck finding the right equipment for yourself.

Cowboy, I'm doing something similar, but slightly different. I have a Behringer Ultra-Q T1951 on the way. 2 channel, 4-band parametric eq, with tubes. (Will go in between the 950 and my ss power amp only for the front L & R channels.) No "bypass," but has a knob to dial in the "warmth" or "tubeness" of the sound, vs "cold". Somehow "mixes" in the tube sound. So "warm" for 2 channel audio, and "cold" for HT. Should be interesting to play around with it.

Any opinions on driving Klipsch RF7's,rated at 102db/watt/meter, with a "755," using a
HK AVR85 as preamp.
This is the post, I was referring to in another speaker thread.
Is this a situation where the 755 would be operating at its lower threshold, at most normal volume levels, producing too much noise?

[This message has been edited by gwhunran (edited April 17, 2003).]

Soundhound,
I always enjoy reading your informative posts. How do you handle the differences in gain/input sensitivity and power of different amps when you horizontal bi-amp? Do you use an active crossover? How about differences in speed and characteristic in the amps. Could it degrade the sound in any way. I use Newform Research moded 645's with crossover set at 1000 HZ between the ribbons and scan speak mid woofers and was always afraid of horizontally bi-amping because of the relatively hi crossover point. I do have a pair of Rogue Mangnum 120's in triode mode driving the fronts with active sub crossover at 100hz (with db Systems active crossover) using one paradigm ps1000 for both channels (yes, I know two would be much better). I do have a 5-channel parassound HCA2205 220x5 which I love that is sitting idle on the side and can use it to horizontally bi-amp. But the problems of gain and speed of the amp have prevented me form doing so. Also I know the Rogues have no problem driving the 96db efficient speakers so I do not know If the benefit is worth the complications. Your insights are appreciated.

Best Regards

Amir

For those intersted the link is to the list for the most exotic horn systems for "music lovers"
http://aca.gr/system_world_a.htm#worldjyk
Now this is what I call the listining room (the second picture)

enjoy

Amir

Thanks for your comments. I have installed potentiometers in all my power amps that control the gain. Otherwise it would be impossible to get the differing amps balanced. The crossover is a custom built job that has crossover frequencies at 60Hz for the sub to woofer, and 1,200 Hz for the woofer to tweeter. Except for the subs, the mains are completely horn loaded.

If there is a difference in "speed" between the amps, I haven't noticed it. All of them have been very extensively modified in similar ways, so maybe this is equalizing out some of the differences. Also, of course, all the amps except for the sub are tubed. The tweeter amp is a single ended triode.

Well SH I will mention that I love my speakers,I have done some demos of more expensive speakers like the B&W 12,000 per pr,but I always come back to the sound of my speakers,they can play at live levels and I just love them,the others you play them loud and they start to compress,no detail and no dynamic range at all.I need to mention that I like the sound of live bands on intimate settings weather is acoustic or electronic.So do I love my horns????You bet I do!!!!