Blind Speaker Test

[randyb]

I plan to do a blind speaker test with the best methodology that I can muster. Those that have an interest and are members on AVS please vote over at AVS. I know that WmAx is very respected here and the Behringer 2030 are in the mix if there is an interest. Any suggestions here are also welcome.
Thanks,
Randy Bessinger

 

[billy p]

I plan to do a blind speaker test with the best methodology that I can muster. Those that have an interest and are members on AVS please vote over at AVS. I know that WmAx is very respected here and the Behringer 2030 are in the mix if there is an interest. Any suggestions here are also welcome.
Thanks,
Randy Bessinger

You should have attached a link.....

 

[Alex2507]

You should have attached a link.....

Thank you Captain Obvious !!!

 

[randyb]

Thank you Captain Obvious !!!

Yes, of course, I should have and here it is.http://www.avsforum.com/avs-vb/showthread.php?p=17532480&posted=1#post17532480

I would like to offer WmAx a free trip to KC to help me set this up. I would love to have him to help and will work with him to make this something that people can point to as a fair test.


Chris PM or email me. Free trip all expenses paid and you can stay at my home or a motel down the street.

 

[Alex2507]

Hey Randy,

I take it that these speakers are in the test and the poll is asking which we think would win. You're not asking which we want to be in the test. English as a second language can be a bugger.

I'm just waiting for Swerd to start chanting "Salk, Salk, Salk !!!" Another of our Chrises 'mperfct' is out KC way IIRC. If he doesn't go I'm not going to speak to him any longer. I'm anxiously awaiting the details of how the test is to be performed and when it is to be done. I guess I might try posting something over there and get my post count up to 2.

Nice rack of chicklets.

 

[Matt34]

Damn, I lived out near KC about five years ago too.

 

[WmAx]

I am kind of surprised you are not using a turntable system so that that each speaker occupies the same space, and with no potential interference from side by side speakers. In your case, it could be non-powered turntables, with simple index catches to ensure exact position, with a person behind the acoustic transparent curtains to switch them to the proper position when needed. The tables could be made simply out of doubled up 3/4" hardwood ply, with hopefully a soft constrained layer between them, and with a simple 1" steel rod with bearing on the center axis of the table, using some nice smooth industrial casters with hard rubber coating and nice bearings around the bottom circumference of the turntables, riding on a smooth cabinet grade ply surface. Each place for each speaker should use some simple method to 'clamp' the speaker in place so it remains stable with rapid rotation. YOu could even make this an active/automated rotation table set - but to do that properly would add several hundred dollars to the parts list if you wanted a high speed/high torque set up that could change rapidly.

Yes, I know I am suggesting twin/stereo turntables, as where the primary Harman articles usually used a single/mono unit. However, I believe the results from twin set up is more conclusive, and takes into account better the off axis properties of the speakers, as a single/mono set up would have far weaker side reflections in ratio to the direct radiation.

I will say that I am eventually, hopefully in mid 2010, building two large turntables for the L and R positions in my dedicated listening room, along with a large acoustically transparent barrier to hide them. I have a real need to do extremely accurate DBT testing with speakers in the future, for reasons I don't want to state on a forum right now.

-Chris

 

[Swerd]

I'm just waiting for Swerd to start chanting "Salk, Salk, Salk !!!"

Chant! We don't need no stinkin' chant.

Salk speakers will wipe the floor with those others.

Actually, I've been curious to know what those Outlaw bookshelf speakers sound like. They use the same woofer as the Salk Song series.

Good luck with effort Randy. I know how much work this can be.

Short of using a turntable, a simple test can tell you just how much different locations may affect the sound. Place two identical speakers in different locations. Listen to one at a time under blind conditions. Try that with several different pairs. Hopefully, you can use that technique to find locations where any differences are minimal.

 

[randyb]

Hey Randy,

I take it that these speakers are in the test and the poll is asking which we think would win. You're not asking which we want to be in the test. English as a second language can be a bugger.

I'm just waiting for Swerd to start chanting "Salk, Salk, Salk !!!" Another of our Chrises 'mperfct' is out KC way IIRC. If he doesn't go I'm not going to speak to him any longer. I'm anxiously awaiting the details of how the test is to be performed and when it is to be done. I guess I might try posting something over there and get my post count up to 2.

Nice rack of chicklets.

Actually, I am asking which speakers you would like to see tested as I am not going to do all of them. I am thinking 4 or possibly 6 pairs being evaluated.

 

[just listening]

Blind tests on speakers usually end up suffering from several fatal flaws, here are four that I have experienced and a potential solution for each. I'm sure that their are plenty more:

1. Each set of speakers is not placed in it's optimal position in the room, usually they are just stuck behind a sheet. Thus creating immediate advantages/disadvantages.

2. Amplification and source equipment is usually of lower midfi quality, and therefore lacks the clarity to be neutral.

3. Proper room treatments aren't in place, creating a very uneven playing field.

4. Listeners are not intimately knowledgeable of the music selections. Anybody who compares speakers at home always plays their favorite material that they know inside and out.

Fixes
1. No more than two speakers should be compared at the same time, this will give room for just about the best positioning of both pairs. It also allows for the usage of a switch box (for at least a part of the comparison though this gets tricky because of spl readings need to be balanced)to quickly go between speaker pairs in order to get immediate comparisons.

2. Amplification & Source gear should be at least $3k in order to bring up the resolution quality allowing the speakers to perform with fewer limitations.

3. Some sort of treatments need to be in place to neutralize acoustical flaws that can clobber some speakers more than others.

4. "Judges" should each have at least one choice selection and have at minimum 2 weeks with the full list of music in order to have a solid knowledge of the songs.

 

[randyb]

Blind tests on speakers usually end up suffering from several fatal flaws, here are four that I have experienced and a potential solution for each. I'm sure that their are plenty more:

1. Each set of speakers is not placed in it's optimal position in the room, usually they are just stuck behind a sheet. Thus creating immediate advantages/disadvantages.

2. Amplification and source equipment is usually of lower midfi quality, and therefore lacks the clarity to be neutral.

3. Proper room treatments aren't in place, creating a very uneven playing field.

4. Listeners are not intimately knowledgeable of the music selections. Anybody who compares speakers at home always plays their favorite material that they know inside and out.

Fixes
1. No more than two speakers should be compared at the same time, this will give room for just about the best positioning of both pairs. It also allows for the usage of a switch box (for at least a part of the comparison though this gets tricky because of spl readings need to be balanced)to quickly go between speaker pairs in order to get immediate comparisons.

2. Amplification & Source gear should be at least $3k in order to bring up the resolution quality allowing the speakers to perform with fewer limitations.

3. Some sort of treatments need to be in place to neutralize acoustical flaws that can clobber some speakers more than others.

4. "Judges" should each have at least one choice selection and have at minimum 2 weeks with the full list of music in order to have a solid knowledge of the songs.

I am with you on all but 2. While the equipment I am using would be more than $3 k total, I am not one that believes you need expensive CD/DVD players (Perhaps WmAx can chime in here). I have a well treated room but to be honest, Sean Olive made a good point to me when he wrote that too much treatment can deaden the room and would make speakers that are both bad and good with off-axis FR sound more similiar. I think he is correct.

 

[just listening]

I am with you on all but 2. While the equipment I am using would be more than $3 k total, I am not one that believes you need expensive CD/DVD players (Perhaps WmAx can chime in here). I have a well treated room but to be honest, Sean Olive made a good point to me when he wrote that too much treatment can deaden the room and would make speakers that are both bad and good with off-axis FR sound more similiar. I think he is correct.

Randy:
I have Musical Fidelity A3.5 int. amp and a Rega Apollo cdp, and for blind testing I won't recommend either even though I think they both offer great value/sound for the dollar. Neither piece offers up enough resolution and color-free sound reproduction.

I think it's foolish to put out such effort and time for a dbt session. Back in 2003 I attended a speaker dbt. The source was a Sony cdp, Apt Holman preamp, and an Adcom 545 amp. All three pieces had been bench tested prior to the event. The gear was way too influential and affected some speakers more than others negatively.

I agree, too much treatment is as bad as too little, or none. The proper amount can have a tremendous positive influence on sound quality.

I'll be curious as to what WMAX says as well.

 

[Warpdrv]

Hey Randy, nice of you to stop here and gather thoughts....

I would suggest you limit your tests to no more then what you already have going now, unless your planning on spending the entire day at this... and people tend to start to lose the freshness factor after so much time running the same songs over and over again....

I wish you guys and your crew of listeners good luck with this project...
Its always a good time to get together with your fellow aficinados for these type of events...

 

[mtrycrafts]

..., Sean Olive made a good point to me ....

Since you are in contact with him, after Tool's retirement he may be one of a few experts on speaker DBT, I am surprised you are seeking other inputs.

 

[corey]

2. Amplification & Source gear should be at least $3k in order to bring up the resolution quality allowing the speakers to perform with fewer limitations.

I think you've got the makings for another DBT here. I'd be surprised if you could find a difference between a $500 amp & source and a $3000 amp & source, as long as the speakers were efficient enough that a difference in power didn't matter.

 

[Amherst]

I think you've got the makings for another DBT here. I'd be surprised if you could find a difference between a $500 amp & source and a $3000 amp & source, as long as the speakers were efficient enough that a difference in power didn't matter.

Very Wrong.

 

[mtrycrafts]

Very Wrong.

How so? Please explain in detail, if you would.
Evidence would help.

 

[mtrycrafts]

I think you've got the makings for another DBT here. I'd be surprised if you could find a difference between a $500 amp & source and a $3000 amp & source, as long as the speakers were efficient enough that a difference in power didn't matter.

I missed that part of his post and wasn't in the mood to rock the boat
A waste of time and energy Many 'golden ears' thought they could until the truth teller was utilized

 

[randyb]

There is some irony here since the dbt equipment i am using was some of the original equipment used years ago by David Clark, Nousaine and others to determine cable and amp differences. Obviously, there is a difference between that crowd and the stereophile crowd-Fremer, Serrius, etc. BUT, this is a speaker test that everyone agrees are different so it is really a preference test.

 

[WmAx]

It's not surprising that some think the hardware (amp, source, etc.) is not good enough to demonstrate speakers accurately unless the hardware costs like $40,000 and is made by some super-exotic manufacturer.

Oh woe is me, with my crappy mid-fi cd player and pro audio amplifiers that I use in my main system....... If only I had a nice stereo.

But in the real world, the source and amplifier contribute FAR LESS distortion(s) than a speaker system - even the best speakers in the world pale in comparison to the low distortion levels offered by even 'mid-fi' hardware. The most important thing is insuring the amplifier used can handle the specific reactive load of the loudspeaker(s) under test without resulting in substantial frequency response modification or clipping.

Despite the many credible blinded tests that demonstrate hardware having no audible difference if it measures the same within known human audibility thresholds, this non-sense of some mysterious audible 'X' factor continues, or worse, someone claims that proper bias controlled blinded testing is flawed compared to sighted, uncontrolled testing. In my view, if one can not understand the basic premise of scientific procedure and the meanings that can be drawn from pre-existing listening tests in this area after it has been extensively explained to them, then such person should simply be flat out ignored IMO in the discussions of such. They are not capable of understanding and the have NO useful contribution(s) and/or criticism(s) to offer in regards to such tests, if they can not demonstrate basic comprehension of them in the first place.

-Chris