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What *does* make a difference?, Doesn't ABXing show more differences on some things?
BearcatSandor
post Nov 8 2010, 06:01
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I've been reluctant to post this because they seem like stupid questions, but my beliefs have been turned upside down so much this week i donno what's "stupid" anymore. So, here i go, even though i'd bet that all three comparisons below would be detectable.

Note that none of this is about perceived quality. It's about not being able to tell appreciable differences via ABXing.

I've been reading up on ABX tests all week and i just give up. I don't get it. There seem to be a few stand-outs such as cables, and devices with D/A converters that don't make any difference, but i'm about ready to throw up my hands in frustration. I just don't get it.

Speakers can be so physically different. I've got the Anthony Gallo Acoustic Reference 3.1's. They are about 3' tall, have rounded "cabinets" around the cones, a cylindrical tweeter and a 10" side firing driver. How can they sound the same as a speaker built around a single fostex driver, or an 8' tall 3' wide Sound Labs panel speaker or a Wilson Audio Maxx ( http://www.wilsonaudio.com/product_images/...groom_large.jpg ).

It is the consensus of the forum that tube amps, class t/d and class A/AB of the same relative power sound the same for the most part? What about different tubes in tube amps? Is tube rolling pointless from a sonic perspective? I mean again, tube amps. and the other types are working in a very different physical manner so how can they not be detectable from one another?

I saw some snickering at room treatments. Is the forum suggesting that room treatments and digital room correction make little to no difference in sound quality? I mean hard/absorbent surfaces do effect what frequencies reach your ears at what times (or at all), so my mind says that logically has to make a difference. Digitally flattening out a response curve has to effect the sound, right? Now, i'm not talking about the *value* of such treatments. Most of the time i see an expensive bass trap or a pricey colorful audiophile pillow that i'm supposed to put on my wall i think "I bet my mate who's a quilter could make me something that would do that same thing or i could just hang a blanket on the wall" Regardless of whether or not you use the $2k room treatment, change your curtains or move the couch for the same effect, the effect wouldn't likely be a placebo would it? Why would recording studios and concert halls work so hard at it?

Bearcat

This post has been edited by BearcatSandor: Nov 8 2010, 06:02


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Josh358
post Nov 9 2010, 03:45
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QUOTE (BearcatSandor @ Nov 8 2010, 00:01) *
Most of the time i see an expensive bass trap or a pricey colorful audiophile pillow that i'm supposed to put on my wall i think "I bet my mate who's a quilter could make me something that would do that same thing or i could just hang a blanket on the wall" Regardless of whether or not you use the $2k room treatment, change your curtains or move the couch for the same effect, the effect wouldn't likely be a placebo would it? Why would recording studios and concert halls work so hard at it?

Bearcat


I agree with the previous answerers so I won't repeat what they said. I just wanted to point out that a blanket or quilt isn't a substitute for a bass trap. You can in fact get many of the benefits of acoustical room treatment using common furnishings -- CD and bookcases for diffusion, curtains for high frequency absorption, etc. Bass modes, unfortunately, are less amenable to that sort of treatment, but can be reduced with careful placement of speakers and listener, the use of multiple subwoofers, and equalization, or changes to the room envelope.

Anyway, the differences in bass response are easily measurable and should be measured, not so much because of the placebo effect (although it could potentially affect a listener's judgment) as the sheer difficulty of juggling loudspeaker position, listener position, acoustical treatments, and equalization to get the best bass response. You can still use the old techniques if you have to -- listening to walking bass, swapping speaker and listener positions, using rules of thumb -- but I don't think you'll get the best results flying blind.
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BearcatSandor
post Nov 9 2010, 19:12
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QUOTE (Josh358 @ Nov 8 2010, 19:45) *
I agree with the previous answerers so I won't repeat what they said. I just wanted to point out that a blanket or quilt isn't a substitute for a bass trap. You can in fact get many of the benefits of acoustical room treatment using common furnishings -- CD and bookcases for diffusion, curtains for high frequency absorption, etc. Bass modes, unfortunately, are less amenable to that sort of treatment, but can be reduced with careful placement of speakers and listener, the use of multiple subwoofers, and equalization, or changes to the room envelope.

Anyway, the differences in bass response are easily measurable and should be measured, not so much because of the placebo effect (although it could potentially affect a listener's judgment) as the sheer difficulty of juggling loudspeaker position, listener position, acoustical treatments, and equalization to get the best bass response. You can still use the old techniques if you have to -- listening to walking bass, swapping speaker and listener positions, using rules of thumb -- but I don't think you'll get the best results flying blind.

When discussing an Ambisonics setup that i want to do, it was advised that i set up a subwoofer in each corner of the room to 'pressurize the room' and provide some cancellation of standing bass waves. Does that follow with your knowledge?

Also, i still wonder if one couldn't just make ones own bass traps. It's just material placed in the room some where in a particular shape. Sure, they may advertise it as a space-aged patented mix of calcified nymph blood and gremlin brains, but i'm skeptical of such things.



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Arnold B. Kruege...
post Nov 9 2010, 21:38
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QUOTE (BearcatSandor @ Nov 9 2010, 13:12) *
When discussing an Ambisonics setup that i want to do, it was advised that i set up a subwoofer in each corner of the room to 'pressurize the room' and provide some cancellation of standing bass waves. Does that follow with your knowledge?


Pushing more energy into a room to alleviate a bass cancellation null is close to mission impossible. Remember that a 20 dB null takes 100 times more energy to "fill". So if you need a 100 watt amp to drive your sub woofer so that it is loud enough outside the nulls, it might take 10,000 watts to fill the nulls. Actually finding that sort of amp is not nearly as hard as finding a sub woofer that could actually translate its power into acoustic energy to fill the nulls.

QUOTE
Also, i still wonder if one couldn't just make ones own bass traps. It's just material placed in the room some where in a particular shape. Sure, they may advertise it as a space-aged patented mix of calcified nymph blood and gremlin brains, but i'm skeptical of such things.


Here is a reliable source of information about acoustical traps:
RealTraps Web Article Archive

If I were going to build my own traps, I'd read up there and then search the web for articles about building traps that were consistent with its wisdom.

This post has been edited by Arnold B. Krueger: Nov 9 2010, 21:39
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knutinh
post Nov 10 2010, 09:57
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QUOTE (Arnold B. Krueger @ Nov 9 2010, 21:38) *
QUOTE (BearcatSandor @ Nov 9 2010, 13:12) *
When discussing an Ambisonics setup that i want to do, it was advised that i set up a subwoofer in each corner of the room to 'pressurize the room' and provide some cancellation of standing bass waves. Does that follow with your knowledge?


Pushing more energy into a room to alleviate a bass cancellation null is close to mission impossible. Remember that a 20 dB null takes 100 times more energy to "fill". So if you need a 100 watt amp to drive your sub woofer so that it is loud enough outside the nulls, it might take 10,000 watts to fill the nulls. Actually finding that sort of amp is not nearly as hard as finding a sub woofer that could actually translate its power into acoustic energy to fill the nulls.

But using more than one sub and positioning/EQ-ing them wisely is not necessarily a waste of time and resources.

-k
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Posts in this topic
- BearcatSandor   What *does* make a difference?   Nov 8 2010, 06:01
- - saratoga   QUOTE (BearcatSandor @ Nov 8 2010, 00:01)...   Nov 8 2010, 06:29
|- - greynol   QUOTE (saratoga @ Nov 7 2010, 21:29) Diff...   Nov 8 2010, 06:50
- - Arnold B. Krueger   QUOTE (BearcatSandor @ Nov 8 2010, 00:01)...   Nov 8 2010, 21:11
- - BearcatSandor   Thanks for the replies folks. That does make me fe...   Nov 8 2010, 21:34
- - Josh358   QUOTE (BearcatSandor @ Nov 8 2010, 00:01)...   Nov 9 2010, 03:45
|- - BearcatSandor   QUOTE (Josh358 @ Nov 8 2010, 19:45) I agr...   Nov 9 2010, 19:12
|- - Arnold B. Krueger   QUOTE (BearcatSandor @ Nov 9 2010, 13:12)...   Nov 9 2010, 21:38
|- - knutinh   QUOTE (Arnold B. Krueger @ Nov 9 2010, 21...   Nov 10 2010, 09:57
- - BearcatSandor   Thanks for the info Arnold. I'm still new at a...   Nov 9 2010, 22:50
|- - Josh358   QUOTE (BearcatSandor @ Nov 9 2010, 16:50)...   Nov 10 2010, 01:07
- - BearcatSandor   Thanks very much for all that Josh. I will look in...   Nov 10 2010, 07:20
|- - knutinh   QUOTE (BearcatSandor @ Nov 10 2010, 07:20...   Nov 10 2010, 09:53
|- - Josh358   QUOTE (BearcatSandor @ Nov 10 2010, 01:20...   Nov 11 2010, 00:39
- - BearcatSandor   This is the email that contains the information on...   Nov 10 2010, 10:14
|- - Arnold B. Krueger   QUOTE (BearcatSandor @ Nov 10 2010, 04:14...   Nov 10 2010, 14:09
- - knutinh   Subwoofers: Optimum Number and Locations by Todd W...   Nov 10 2010, 20:24
- - item   QUOTE (BearcatSandor @ Nov 8 2010, 06:01)...   Oct 8 2012, 19:41
- - greynol   Not only is that overly-simplistic, it is simply n...   Oct 9 2012, 05:10
|- - item   QUOTE (greynol @ Oct 9 2012, 05:10) Not o...   Oct 9 2012, 12:33
|- - probedb   QUOTE (item @ Oct 9 2012, 12:33) Of cours...   Oct 9 2012, 12:54
|- - item   QUOTE (probedb @ Oct 9 2012, 12:54) QUOTE...   Oct 9 2012, 14:17
- - greynol   If not trolling it does demonstrate a gross lack o...   Oct 9 2012, 15:37


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