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Re: Questions about bass management
terzaghi #191513 01/11/08 12:49 AM
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Audessey and just about every other auto-equaliztion program found in the Denons, Pioneers and Yamahas etc. are notoriously bad at setting anything related to frequencies below 100hz. I would ignore any sub, delay or crossover setting and adjust manually. Simply not enough processing power in the receiver chips to find the optimal LF settings.

Here's a few suggestions.

1. For HT don't set the M80's to large because you are duplicating the LFE channel when using Dolby digital tracks as well as introducing phase and other artifacts when in stereo mode. I would suggest turning off the EP500 and just listening to the M80s full range for music if the Denon has such a setting.

2. Set all speakers to small and cross as follows (based on 1/2 octave above low -3db extension for the M80s and close to -3db the other speakers).

M80s 50hz
vp150s 80hz
qs8s 100hz

3, Listen for a few days and then cross all speakers at 80hz. The reason I am suggesting this is that the Denon power rating at 130wpc is likely not accurate for all channels driven so you may benefit sonically from easing the power demands on the amp by crossing the m80s higher. Also keep in mind that depending on the slope of the Denon, which is likely -12db/octave, you are still getting output above the crossover frequency redirected to the EP500 which brickwalls at 100hz. You can also try leaving the qs8s at 100hz.

Depending on your room and your listening habits I suspect you should find an improvement. ;\)


John
Re: Questions about bass management
jakeman #191514 01/11/08 12:57 AM
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I'll give it a shot and see what I think.

Thanks for the advice.


-David
Re: Questions about bass management
terzaghi #191532 01/11/08 02:15 AM
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>> Just cuz I've got 5000 posts doesn't mean I've learned anything

I've never learned anything by posting. It would be great to have a score for the number of posts we have *read* ;\)

The HK receivers don't let you pick a separate frequency for LFE cutoff but they do let you pick a speaker set (main, center, surround) and have LFE cut off at the same frequency as that speaker. That works pretty well for me as I can cross over the M60s at 80 Hz and the rest at 100 Hz, then pick "surrounds" for LFE to get a 100 Hz cutoff.

I still have a nagging feeling that the system sounds better when all the crossovers are set to the same frequency but have never had the time nor patience to do enough testing to be sure.

Last edited by bridgman; 01/11/08 02:19 AM.

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
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Re: Questions about bass management
autoboy #191533 01/11/08 02:20 AM
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I used to like that site for the DVD benchmark charts but now, forcing to register to read content of interest is aggravating.


"Those who preach the myths of audio are ignorant of truth."
Re: Questions about bass management
bridgman #191535 01/11/08 02:28 AM
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Only one way to find out for sure John. \:\) Having debated this one at length at other forums I'm of the view that if there is a difference the greater effect comes from artifacts which may be created in the summation not by some concern over whether a gap is created which is inaudible and gets overlapped by the slope. Its all academic because no one can tell if the artifacts are there or not and the difference if it exists is swamped by room acoustics anyway. That's why the author of the article hasn't gotten much replay in the 5 years since it was written. Yet another example of a theoretical concept which does not translate into real world listening applications.


John
Re: Questions about bass management
jakeman #191541 01/11/08 03:01 AM
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 Originally Posted By: jakeman


1. For HT don't set the M80's to large because you are duplicating the LFE channel when using Dolby digital tracks as well as introducing phase and other artifacts when in stereo mode. I would suggest turning off the EP500 and just listening to the M80s full range for music if the Denon has such a setting.



I think you misstated this. The Denon LFE+Mains setting does not duplicate the LFE channel. It only copies the signal below the crossover setting that is being sent to any speakers set to large and also sends it to the subwoofer. The LFE channel plays only through the sub as long as the subwoofer is set to “yes.”

First off I don’t dispute the phase and other issues you mentioned or the benefit of not burdening speakers with playing very low frequencies since that’s what the sub specializes in.

But this brings up a question I‘ve been wondering about for some time. If duplicating low frequencies between the “large” speakers and the subwoofer can cause so many problems why do so many people recommend using multiple subwoofers to even out the bass? Won’t the same issues apply or does evening out the bass outweigh the other issues most of the time?


3M80 2M22 6QS8 2M2 1EP500 Sony BDP-S590 Panny-7000 Onkyo-3007 Carada-134 Xbox Buttkicker AS-EQ1
Re: Questions about bass management
grunt #191546 01/11/08 03:25 AM
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Thanks for clarifying it and I agree with you. When he stated he set the M80s to "large" ( as opposed to small) I intrepreted that to mean he was running them full range and not crossed which would have duplicated the LFE channel. \:\)

 Quote:
But this brings up a question I‘ve been wondering about for some time. If duplicating low frequencies between the “large” speakers and the subwoofer can cause so many problems why do so many people recommend using multiple subwoofers to even out the bass? Won’t the same issues apply or does evening out the bass outweigh the other issues most of the time?


One of the biggest challenges with integrating subwoofers is getting the speakers and sub(s) to blend properly with as flat FR as possible and minimal phase interference. Getting the speaker/sub frequency interface as smooth as possible is best achieved when you have the low pass filter (frequency and slope) at the crossover point producing a smooth summed response from the sub and speaker. If you have the speaker producing LFE and essentially no low pass filter operating it becomes next to impossible to blend the sub and speaker so the net outcome is more room reinforcemnt and cancellation and phase problems throughout the low bass range.

Now if you have the speakers low frequency output filtered out and you have it crossed to the subs it effectively removes one set of problems to worry about ie. resulting from uneven FR between the sub and speaker. There are other concerns such as getting the multiple subs behaving in a linear fashion but that can be achieved if the speaker interaction is set up right.
In other words getting flat FR in room is easier with the speakers crossed to the subs.

As you go from one to multiple subs studies (such as the famous Harman study on multiple subs) have shown that the greatest benefit to achieving flat response by reducing nodes throughout the room happen when you add a second subwoofer. Adding additional subs helps further but not as much with four subs being about the limit for further improvement in flattening FR. Getting them placed properly and operating in phase is another involved topic but the benefits are clear with less need for room treatments or equalization. A couple of years ago out of curiousity I bought 3 EP 600s and 2 EP500s to see for myself and 4 subs does provide the optimal benefit.






John
Re: Questions about bass management
jakeman #191549 01/11/08 03:42 AM
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Thanks for the explanation of the speaker subwoofer crossover part of the problem. I still have questions about how to get multiple subs to behave in a linear fashion but I don’t want to hijack this thread so I might start another one later.

Dean


3M80 2M22 6QS8 2M2 1EP500 Sony BDP-S590 Panny-7000 Onkyo-3007 Carada-134 Xbox Buttkicker AS-EQ1
Re: Questions about bass management
grunt #191550 01/11/08 03:45 AM
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Go ahead and I'll see if I can help. After all we are talking about bass management and some of this stuff can only be figured out by actually going through the process.

I've sold most of my EP subs but recently added some sealed subs to my HT so I am back to having a quad of subwoofers throughout the HT.

Here is an informative discussion by Ian on the topic of multiple subs. He goes through a good summary though I find getting the phase between multiple subs set up properly takes more effort than what is being suggested.

http://www.axiomaudio.com/videocenter.html


John
Re: Questions about bass management
jakeman #191603 01/11/08 06:02 AM
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I find that when I cross over at 80, the bass is too "fat"
and, dare I say, "slow". It also distracts from the fine details of the music and doesn't provide the right "punch".

Also, when I use LFE+mains, the bass is over-powering. I tried a 60Hz setting like John suggested but I still find it too "fat". 40Hz sounds just right for music and movies. So I paid roughly $100/Hz for the 600 and about $0.07/Hz for the M80s. The 80s are a steal \:\) .

Of course all of this is configuration-dependent so every one should tweak until it sounds just right for them.


House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated
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