basic theory behind what we do - Page 5 - Home Theater Forum and Systems -

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post #41 of 44 Old 07-29-08, 08:17 PM
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Re: basic theory behind what we do

mas wrote: View Post
Then others who expressed confusion over the limitations I had quickly mentioned stated that others were quite happy with using EQ. As I was concerned with limitations regarding its use for the general use in altering room response other than in the limited situations originally stated (LF modal peaks and minimum phase regions) I am not sure what their point was (as the link did not work for me).
Sorry 'bout that. The link is fixed now, but here it is:

"The point," admittedly subtle, was that the Member in the thread linked was very pleased with the equalization he enacted, despite the declarations of any number of "nay-sayers" that such a thing can't be accomplished. I've been happy with mine, too.

I then provided several links which address some of the legitimate uses and the very limitations to the use of EQ to which I asserted and was then told that acoustic references from pro-audio sources, because they are considered from 'pro' sources, are somehow invalid in 'amateur' acoustics - a distinction which is curious to me as within the limits of similar atmospheric conditions, large acoustical space and small acoustical space acoustics are the same - be it for pro or amateurs!! A very curious distinction!
I said or inferred no such thing. You might want to read my post again, perhaps a little more slowly.

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post #42 of 44 Old 08-01-08, 09:23 AM
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Re: basic theory behind what we do

Spatial temporal averaging using a RTA is more effecient than using a microphone mulitiplexer. It's also easier.
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post #43 of 44 Old 08-03-08, 11:31 AM
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Re: basic theory behind what we do

How many possess a sufficient understanding of modern acoustical models such that they can delineate the limitations of equalization?

I stuck a digital eqaulizer in my system, played around with it and now have a much improved listening experience.

That's all I really know.

It's not all I'd like to know and I have read a bit on acoustics. I think in fact that I have, accidentally maybe, addressed some of the other, non-frequency, problems mentioned by using room treatment and listening near field.

It's nice to know all the above technicalities but is it really nescessary. I think not and shouldn't be condemned for it!
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post #44 of 44 Old 08-03-08, 06:50 PM
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Re: basic theory behind what we do

seems we here 'fall between two stools'...and can get criticized whatever we do.

We at least are attempting to take steps to do something to correct the most egregious errors in our systems that ALL who have systems are subject to, and about which most dyed in the wool audiophiles have either no inkling of or sneer that 'mere equalizers' can have any positive benefit.

We are at least taking some responsibilty for our systems and not relying on a new 'gold plated silver interconnect with special connectors' to 'fix our sound'. (usual hifi a new component)

Yet, to some, we are also not going far enough and displaying woeful ignorance...looks like we can't win. And the proof of our woeful ignorance??? in depth obscure mathematical and latest research in the field, which to us mere 'joe blows' looks like it requires one to be fully and actively employed in the profession to be even aware of, let alone able to comprehend and use the data.

Not all of us live, work and breathe stereo (tho maybe we would like to!!), and simply do the best we can in the time available to us.

Seems we can't win.

Do I have anything positive to contribute?? maybe, atm I think so but I guess I'll soon find out heh heh.

I use a deqx in my system, which interestingly enough seems to address at least some of the issues outlined earlier, ie steep linear phase slopes between the drivers and the actual correction of the drivers and their phase relationships themselves, as well as time alignment. So, at least some sort of serious attempt has been made to start with the best speaker platform we can.

After all that, traditionally as a last step we would do peq of the room to provide a 'flat response'. This seems to be the main point of criticism in this thread, and yes (at least to my limited understanding) I can see the point. Nonetheless, even tho it is not 'optimal' and incomplete, I can assure you I would rather listen to it corrected than not.

Recently however a change was made in the methodology of the room correction. Instead of measuring the bass driver (either near field or as anechoically as possible) and then 'correcting the driver' prior to the room correction, instead the bass driver was measured from the listening position for the correction, and so had the room response contained within the bass drivers response. By then correcting the combined room and bass driver (this step is where the dsp also corrects for phase and group delay) an attempt is made to also correct the room induced phase anomolies as well as the bass driver. No doubt technically I have a lot of that wrong (dumb monkey understanding of the complexities, so no correspondence will be entered in to as dumb monkeys can't 'correspond' heh heh) but as I understand it there is now much more 'reading and correction' of time isuues as well as amplitude issues.

$64 question?? A surprisingly big, big improvement. From an FR perspective the result 'is the same' (ie flat or whatever you want), gee big difference in the sound and coherence of the result.

And it's quite easy to see the extra work required to get the result, when measuring and correcting the driver alone it may take say, 'x' seconds for the computation. Doing it the above way, dunno, twenty 'x' seconds or whatever. chugging, chugging, chugging away doing the computation. That must be a result of all the complicated etxra time/phase info contained in the signal.

Dunno if what I've described even comes close to meeting some of the objections outlined here, but I can assure you that without going to uni and immersing myself in the minutiae (undoubtedly important tho it is) I've reached about the limit of what this little black duck is capable of...and I feel I've done more than the overwhelming 'vast majority' of the audiophiles in audiophile land have done.

So some of the comments (or the way they were expressed) do come across as a tad insulting or condescending, esp given what seems to be the degree of expertise needed behind them. I mean I could just as easily get on my high horse and throw terms and concepts from my background and point to the latest research in my field and hence criticise you for not understanding them. Why should you understand or be aware of them?

Same here, not all of us have the luxury of being up to date.
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