Heyaz! I've had my 950 for 5 days & I'm still experimenting with diff settings. My old receiver was a Pioneer Elite VSX-41 (basically an 811s)
as a Preamp with an ATI 1506 amp. On the old receiver, I left the tone controls flat & used either loudness or "midnight" mode for warmth. My speakers are Klipsch RF3,RC3 and RB3 (bright by nature) with Polk in ceilings as the rear surrounds. I'm using my ears & failing memory to compare. I was receiverless for 2 weeks prior to getting the 950. Anyhoo, while I'm not absolutely certain, it seems like I was getting more volume from the Pioneer. I don't listen to music/movies at ear bleeding levels regularly, just for tweaking, testing and occasionally jamming. What's a good MAX setting for volume? For most sources, I can't seem to get past -04 to -00 without sending the ATI amp into the red zone even though my ears could probably handle more.

TIA

Jeff

The first thing you should do is calibrate the 950's trims by use of the internal noise generator, and a RadioShack analog sound level meter. You should calibrate with the main volume at "00" and set the trims so that the reading on the sound level meter is 75db for all speakers, with the meter's weighting at "C" and the response set to "slow". Using these settings, the volume at "00" will yield the same volume that they mixed the movie at when watching DVDs, and pretty darn loud at that setting when playing CDs.

SH, having calibrated exactly as the manual and you described above brings up a question I'd been meaning to ask.
My Subwoofer is a passive 4 ohm 12" driven by a bridged Adcom 555II. This amp is rated at 200 Watts p/ch into 8 ohms. Now I cannot find the manual to give exact figures but you can figure this sub should be getting gobs of power right ! I figured the amp may very well complain about this load, even though it is claimed to be stable into 1 ohm. It is not distressed at all ! Hell it doesn't even get warm, which makes me wonder if the thing is working correctly in bridged mode. It is designed to be switched from Stereo to mono and 2 channel to single if one so desires. I used it for years without fault in stereo mode.
My question is this ... Why do I have to completely max out the gain within the 950's speaker setup for the LFE, and almost max out the gain on the ICBM also, to get the same db reading as all my other speakers ?
I would have thought this sub setup would have had to be tuned below the others by a considerable amount, so I'm missing something here !
Perhaps the 950's test signal is not optimized for subwoofer response (ie. too high in frequency) I think I'll draw up a response graph using a test disc. Could be a 20-25 hz signal might move my walls and otherwise detract greatly from the spousal acceptance factor that is already teetering somewhat !


[This message has been edited by Kiwi (edited February 06, 2003).]

Kwi

In bridged mode, you should not attach a load lower than 8 ohms. I would check your manual for the amp to see if they have any other specifics.

I just set the subwoofer by ear most of the time. I have a spectrum analyzer but when tuned for flat, the subs aren't loud enough for my tastes. You should have no trouble getting sufficient volume out of your sub. Maybe the power amp is going into protection mode with the 4 ohms in bridged mode.

Kiwi, I agree with Soundhound. Even though the manual for the 555II says you can use it in bridged mode to drive 8-ohm and 4-ohm speakers, any speaker that drops "substantially" below 4-ohms is not recommended. By the way, the manual says "...when any amplifier is operated in bridged mode, the load is split between the two amplifiers in the bridged configuration. Therefore an 8-ohm loudspeaker will be seen by the amp as if it were a 4-ohm load; a 4-ohm load will be seen as a 2-ohm load." Best wishes.
edited= you only have one sub and amp right?

[This message has been edited by steves (edited February 07, 2003).]

Well guys,I just got home from the hospital were they perform back surgery on me,so I might be still high from the drugs,but my Adcom 555 is rated at 850 watts at 4 ohms continuous,I am using it to power a SVS 25-31CS PLUS tune to 20hz,I have it calibrated at aproximatelly +3db's hot and I have never had any problems with my amp.I may some times bottom out my subwoofer,but my 555 never clipps in bridge mode;and I am playing at almost Dolby Digital reference levels (which are -2 db's under reference)Also when I bridge my amp my gain seems to incres by 3 to 4 db's.Just my two centes. J.R.

J.R.-- Good info! The 555 is a beast! I have a 555II which I use to drive my subs- but have wondered about how it would perform in bridged mode driving one of the SVS subs- if I were to get one. I hope your back surgery works out for you, and you re-coop soon. Best wishes!

I realize a bridged amp sees half the impedance supplied to it, and at the same time realize I am probably stretching the amps limitations, but figured the worst that could happen is to pop a rail fuse. The Adcom 555II amplifier has been used to do the very thing I'm asking of it. Manual also says a load no lower than 4 ohms should be applied in bridge mode. Personally I think my amp is having a problem internally combining the output of the 2 channels. Time for some testing.

The way the bridging works is that one channel is inverted in polarity at the input of one channel of the amp, and the other channel remains as before, then these are sent to their respective power sections. That way one channel of the amp is "going positive" as the other channel is "going negative". By connecting the speaker to the two "hot" terminals, the effective voltage delivered is doubled, which equals an increase in power in watts by a factor of 4.

By constructing a simple polarity inverting stage, almost any two identical amplifiers can be bridged in this manner, such as two of the 200s (although Outlaw would shoot me for suggesting such a thing )



[This message has been edited by soundhound (edited February 07, 2003).]

Wow, you are too much SH !
I've since found my manual and apparently I should get around 850 Watts bridged into a 4ohm load. The GFA555II is stable into 1ohm if the manual is to be believed. This amp worked perfectly in stereo with each channel driving 4ohms, so any ideas as to why my output is so low. Amp has front mounted thermal and distortion alert bezels which in the past seldom ever flashed, and do not at all now.
With the 950's gain on max and the ICBM (placed between 950 & 755) also on max, I'm getting 75db 1 meter from the sub, using the 950's test tone and volume set at 00. My gains for the 5 speakers on the 755 are in the negatives to get 75db @ volume 00 at the central listening position.
Somethings askew yes?

Hey Eurorom,
Hope you are recovering well from the back surgery. Lots of time to listen to your system, yes?
I would love to hear more about how you have your Adcom working and what Outlaw equipment you have associated with it. Would you mind e-mailing me, so we can compare notes. I am still not getting anything close to the output that you are from your bridged 555II into a 4ohm sub.

Also, most subs have one or more impedance peaks in the 25-50 Hz range due to resonances, as well as climbing impedance with frequency due to voice coil inductance. In the cases I've actually measured or modeled it was more a case of impedance sometimes dropping to 7 ohms or so more than hovering around 8 ohms and dipping lower, if that makes sense. Taken as a broad band average from say 80 Hz down my current set of subs are something more like average of 13 ohms, with a ~7.1 ohm minimum.

[Warning: Some English was used to form the above]

Anyway, Euro, get well.

Regarding bridging, I wish the Outlaws would make their multi-channel offerings at least partly bridgable. I bet more than one person would get a 770 for 5.1 if they could do things like bridge for more power on the mains or bridge for a powerful subwoofer amp.

Well Kiwi I am still in pain so I have to take some pain pills,I guess is going to take 6 weeks for my back to heal,thanks for asking.Now on a second note,my Adcom 555 is bridge and powering a SVS 25-31CS-PLUS rated at 500 watts at 4ohms with peaks of 1000 watts, so the manual states,but I do not think the subwoofer can handle the 1000 watts.I used the 555 in stereo mode and it would clip in some sequences for example the Monsters Inc.(the sock event)and Minority Report(the manufacturing plant gun shots on DTS)so I bridge my amp which according to the manual it is rated at 850 continuous and now I get my SVS to bottom out without getting my 555 to light-up the lights.I also did the same thing with a Carver amp rated at 1000 watts at 8 ohms in bridge mode,but not rated at 4ohms;well the amp would go into protection at some loud levels,the reason beign that the Carver is not rated at 4ohms in bridge mode.I also used the Carver(1.0t)in stereo mode which is rated at 200 watts per channel at 8 ohms,and 400 at 4ohms with the SVS but did not get the weight and authority that the Adcom 555 gave me in every mode.Also the 555 is rated at 27 gain in stereo mode,and 30 in bridge mode,so by bridging your amp you would automatically gain 3db's of output.So how sensitive is your sub at one meter?What is the wattage rating at 4 ohms?And how many feet are you seatting from the sub?Oh by the way I am using JBL Studio Monitors Bi-Radials two ways that out-put at one meter 119 db's,and the SVS keeps-up with them,NOT as good as my old JBL-Pro Subwoofer,but because of space the SVS will do for a while....(remember if I mispell I am on medication)

There is a difference between thermal capacity and physical excursion limit, and so this makes it tough for a speaker manufacturer to generate a meaningful power limit. Full range speakers get even more tricky. It is, for instance, a rare tweeter that can really handle a 50 watt signal.

Hi Euro,
I, for one, do not need medication to misspell, although the idea is appealing HAHA!
Relax, heal slowly and listen to music!
My sub is 95db efficient and supposedly handles 600WattsRMS /1000Watts peak. I measure outout with the prescibed R/Shack meter (C weighted/slow response) at the seated position 15 feet from the sub which at this stage is corner loaded in a 23x 14 room that is loaded with typically cohabitant family stuff. Baskets and wife s..t everywhere, you guys get the picture i'm sure! Took me hours to stop all this crap from rattling and messing with my sound ! (Hooray for bluetac!)
This is a very high quality, and expensive, Pro driver from Kenwood, professionally assembled in a ported enclosure, but I doubt very much it would handle 600 Watts. I have in the past attended a Kenwood demo and heard this sub really crank at surprising levels, so in retrospect perhaps the design is off the mark ! Hmmmmmmm - never considered that !
I previously drove it with one of Madisounds pitiful sub amps, but my output now is actually no more than then !
My own take on my problem is that the eventuating LFE line output voltage at the Adcoms input is just not nominal. I have the ICBM between the 950 and 755 with the LFE from the ICBM running to the Adcom.
I do however, have the ICBM switched to special (36db slope), and have not tried the 12db normal setting, as I hate midbass creeping into a subs channel, but maybe I should try this !

[This message has been edited by Kiwi (edited February 13, 2003).]

Kiwi,Let's go over some trouble shooting here,your sub is very sensitive for a sub,and you are not too far from the sub(main seating ares)so let's go over your connections.For mono operation,the Stereo/Bridge switch on the rear panel should be placed in the bridge position.In the Bridge mode only a single input cable is used.The input cable to the GFA-555 should be into the RIGHT CHANNEL input only. When connecting a singlespeaker to the GFA-555 in bridge operation,the positive terminal of the speaker should be connected to the RIGHT channel positive(red) outpost on the 555.The negative terminal of the speaker should be connected to the LEFT channel positive(red) output post.Remember that when connecting the speaker wires,you should maintain proper phasing to obtain maximum bass response.Now check with your manufacture on you sub,to see how the polarity of your sub works,since some are invered in the inside by mistake. Hope this helps,best of luck.