every tower speaker, center channel speaker and surround speaker worth a damn has a passive 2 , 3 or 4-way crossover built in.

the only way high pass filtering the signal to any of those speakers before the amp makes sense, is if they are a single speaker that isn't meant to receive a full range signal (ie, live sound setup, bi-amping or tri-amping).

therefore...all speakers should be set to LARGE.

that leaves the lfe channel. i have yet to read one single word that details the 950's dsp "precision bass management" feature, especially, what happens to the lfe signal with sub set to 'no' and with the high pass filters set to any choice.

someone point me to the correct page, please.

if i assume what has been posted in this thread to be actually the answer to my question (sub set to 'no', lfe is digitally 'y-jacked' and sent equally to L/R mains along with any info from channels set to SMALL below whatever high pass point may have been selected), then:

a.) your sub, or subs are receiving double bass in all formats.
b.) your mains are receiving less than a full range signal, even though they are set to LARGE.
c.) you have phase problems, even if all SMALL speakers are set to the same crossover point.
d.) your setup is less than setting the sub to 'yes', as you would have full range to the mains that way, otherwise it is no different than the 'standard' setup.

bass management is actually very simple...

a.) set all speakers to LARGE.
b.) buy a sub with an onboard bypassable preamp, adjustable phase control, parametric eq (optimized for lfe) and variable low pass filter.
c.) connect the analog lfe output of your DVD player directly to the sub.
d.) set the sub to 'yes' (nothing is connected to the prepro's .1 output)

no double bass, no phase problems that can't be easily adjusted on the sub's front panel, good sound for HT or any music format.

am i crazy? stop by and listen. i've painstakingly tried all three setups with every combination of crossover setting. this setup works....and grandma handles it very easily.
soundhound...you are a bad influence...i am not used to margaritas at all, much less a pitcher full! though,it sounded like a good idea at the time.

I'm sorry but that's not always true. Many people, including me, have speakers that play low frequencies but not loudly, without distorting, awfully. The same speakers play higher frequencies loudly without distorting.

I think you would agree that for these speakers, I should use high pass filtering, rather than hear distortion (and risk speaker damage).

Will

[This message has been edited by Will (edited October 12, 2002).]

will: i do agree that the so called bass management is for people who have small speakers. these are usually the surround speakers and the center channel speaker.

unfortunately, the bass is not managed very well at all and the confusion as to what actually happens to the bass is apparent by reading this thread or any article on the subject.

all 5 speakers should be identical and full range. short of that, the thx spec of setting all 5 speakers to small and xover at 80 for all 5 is the surest option, though it has the incurable double bass problem.

mixing large and small speakers leads to less than optimal listening.

if you have a 950, a good sub or subs, 5 or 7 channel amp, 1080i monitor, good dvd player with sacd or dvd-a and pt barnum interconnects and cables....why would anyone let the speaker setup compromise the best performance possible?

Bosso:

Sounds like the setup you describe will handle it all, and very handily. My grandmother might have a bit of trouble setting it all up though, your grandmother's milage will obviously vary.

I don't know however how you get the conclusions of double bass, phase problems, etc. in my particular setup. The surrounds send any bass below 60hz _supposedly_ to the L&R fronts. The LFE is "Y"ed to the L&R fronts, and the center's bass is likewise "Y"ed to the L&R fronts. Now, from recent posts about the possible workings of the 950s 'bass management', I could be totally, and completely and utterly _wrong_ about my faith in the steering being what I assume it is. The only way this could be checked out for sure is for me to buy that Dolby Digital mastering software for my workstation so that I could make a test DVD. I've been putting that off since it's expensive, and I've not had a huge demand for what it does. Maybe that time is coming.

All my speakers are very capable of running 'large'. I am seriously going to re-evaluate running them that way, and only running the LFE to the main L&R for distribution to the subwoofers by the external crossover. Actually and truthfully, the only reason I started running the surrounds in 'small' is because I was driving them so hard during the storm opening scene in "Twister" that the woofers hit bottom with a big 'snap' - I'm sure you know that sound! The reason I started doing it for the center is because it sounded a bit tubby, since it sits on the floor (it has two 12" woofers).

I have to admit that I don't _hear_ anything unusual that would suggest double bass/phase problems etc. when listening to DVDs, but I might just change them back to 'large' after all. I do most of the really critical listening to my system with the 'mixing console' path, so when I listen to a DVD, I kind of lower my critical standard. And besides, in the mixing console path, I feed full range signals to all the speakers anyway, since I don't use any bass management on anything other than the 950.

Anyway, Tweak time!

[This message has been edited by soundhound (edited October 12, 2002).]

Bosso, since money's an issue for many people including me, and since the front speakers usually have more sound and dynamics than the surround speakers, a case can be made for using better speakers in front and lesser speakers as surrounds. It's cheaper than using identical large speakers, all around. And should sound better in general than using small speakers all around. Using small speakers all around would not be a better solution, unless there's as much sound and dynamic range from the surround speakers as is from the front speakers. I'd love to get full range speakers all around, but can't afford it. Fortunately unlike Iggy the Dog, I don't have sensitive dog-ears.


[This message has been edited by Will (edited October 12, 2002).]

The new $3500 Anthem AVM-20 v.2 THX ULTRA2 programming recommends that you simply set your global crossover to the THX rec of 80HZ. Last I checked... the Outlaw unit allowed that as well.

[This message has been edited by merc (edited October 13, 2002).]

SH: you hit the nail on the head earlier...it really IS harder to write it in logical order than it is to visualize.

i'll try, nevertheless.

bass below crossover (60hz in your case), summed with lfe (bass below 120hz) and bass to mains (as low as the program), equals double bass. if you low pass that combined signal to your subs at 60hz, your subs get the bass info below 60hz from the L, R, SL, SR, center and lfe signals.

there is most certainly a phase issue there, but, if you don't hear one, that isn't a big problem (though i can't imagine what 2 18's driven by 1,000 watts sounds like either way...and, by the way, on that subject...too cool). the main problem is that you have double bass in the subs. it ain't a bad thing either, but you have trained ears...you would hear a definite difference with full range to the mains and only lfe in the subs.

and btw, you don't have dbl bass in stereo with your setup, in fact you have the ultimate stereo setup....must sound very good.

I'm missing something here. The defintion of a crossover is that it high passes the mains (center, surrounds, and rear(s)), and low passes the sub.

Any time alignment should happen *after* the summing and crossing over. (That just makes engineering sense.) (The 5.1 analog inputs are a difderent story.)

I have spent a nontrivial amount of time making sure with discrete tones that my mains are in phase with my sub.

Am I missing something here?

bosso...



Actually your statement above isn't true. You might be quite surprised how you can improve both bass frequency accuracy in the room and the mid-bass to mid-range clarity of your main speakers when you high-pass tower speakers. You actually reduce the THD of the tower's bass/mid-bass driver.

You also said;



Remember, there is an active xover splitting all the bass going to the main channels between the mains and the sub(s). So your point (a) is false, point (b) is obvious, point (c) is false.

In your setup as you specified above, if the lfe is decoded from the DVD player and the rest of the channels are decoded from the processor, do you think they are actually timed correctly? I doubt it.

Have you used a professional MLS based acoustic measurement system and observed the waterfall charts in the bass region? Note any bass frequency timing anomolies? With your setup I would expect to see timing problems between the DVD and processor DSP outputs.




[This message has been edited by bstan (edited October 12, 2002).]

bstan:
a vented enclosure will benefit with a 2nd order high pass filter before the amp, but...the high pass frequency and the Q must be very specific to the driver/enclosure, otherwise, you'll get a huge bump or hole (depending on the Q of the high pass filter, which is not published by any prepro man. that i know of, and therefore not predictable) at crossover point. give me your driver parameters, enclosure volume and vent specs and i'll e-mail you the graphs at all crossover points available on any prepro.

i am aware that there is an active crossover "splitting ALL THE BASS going to the main channels between the mains and the sub(s). to make it simple, take a low E bass guitar signal (approx. 42hz.) that is mixed into the lfe channel. simultaneously, there is the same key struck on a piano that is mixed into the L&R surrounds while a midi kick drum of approx. the same frequency is mixed into the mains. all three signals are now summed and directed into the sub(s) slipping under the 60hz. low pass point....double bass (actually, triple bass). not to mention, the producer's meticulous efforts are negated.
some of the harmonics of those 3 occurrences of a 42hz note remain where they are supposed to be (in this case, above 60hz) and may give the illusion of being correctly placed, but the whole idea of discreet music formats is null and the bass is muddied, exaggerated at the crossover point and out of phase.

the phase problems come from the summing of the bass signal of channels with different high pass points (ie, center at 100, surrounds at 60, mains at 40) with the lfe signal. read the article brianca provided the link to above.

as to the timing problem in my setup, it is not so easily, yet definitely corrected by a delay adjustment at the sub's crossover. (remember...the same delay problem exists within the design of most main speakers and is not adjustable, but that's another discussion in itself)._



[This message has been edited by bossobass (edited October 12, 2002).]