Listening Test Results Axiom EP500 vs SVS PB12-Ultra

Arttu

Standard Member
jakeman said:
You will find below a comparison which was prepared at my instruction in 4pi space (hanging the sub 70ft in the air on a windless day) and measured with the most advanced LMS software. In contrast, the measurements of the Axiom EP600 taken in the finnish shootout used less sophisticated software and was done in 2pi (on the ground) on a cold day which was not a true anechoic environment.

What does the finnish shootout have to do with your tests?
That type of testing resulted in less meaningful measurements.
Huh.
 

jakeman

Standard Member
It did not have anything to do with the listening tests. Just making a point regarding the advanced software and more precise measuring technique used in the accompanying graph compared to other measurements I have seen of Axiom subs at AVForums . :lesson:
 

AngelEyes

Distinguished Member
Hi Chaps,

Can you explain a few things to me that I am not clear on.

How were the subwoofers setup? Were they 'tuned' to the room with any kind of PEQ etc or just 'plonked' down in similiar positions?

Why was the Axiom tested with +5db and not the Ultra and why would you compare two subs at different settings?

Sorry if i am being a bit thick i am just trying to understand things a bit better. :)
 
C

craigsub

Guest
AngelEyes said:
Hi Chaps,

Can you explain a few things to me that I am not clear on.

How were the subwoofers setup? Were they 'tuned' to the room with any kind of PEQ etc or just 'plonked' down in similiar positions?

Why was the Axiom tested with +5db and not the Ultra and why would you compare two subs at different settings?

Sorry if i am being a bit thick i am just trying to understand things a bit better. :)

Hi AngelEyes - some answers ...

1. The subwoofers were level matched with an Earthworks M30 Microphone, M-Audio Mobile-Pre for a soundcard and TrueRTA software. See #4 below for any differences between the two in regards to SPL.

2. They are both run from the same spot in position about 2-4 meters from each listener.

3. They were EQ'ed to within +/- 3 dB from across the band.

4. The EP-500 was used twice - once "flat" and once with a 5 dB bump centered at 25 Hz. Other than the "bump" at 25 Hz, it was the same SPL as the "regular" EP-500. The panel overwhelmingly favored the "Flat" EP-500 to the "25 Hz boosted" EP-500.

5. The Ultra was used twice - in 16 Hz and 20 Hz tunes. We found the 16 Hz tune to measure much flatter when using the higher resolution LMS software - and blind listening tests, including this one, have shown a preference for the SVS in that configuration.

I have been around blind tests since the late 1970's, and have found that doing something unexpected keeps panel members honest. By running only 2 out of a possible 6 subwoofers when the panel assumed there would be four subwoofers here, ALL guessing games were eliminated, and the panel had to go with sound quality.

This may also have gone unnoticed:

Three panel members have SVS as their ONLY subwoofers.

Two have sealed subwoofers - one Rocket UFW-10 and one custom built with Quad Tumults.

One owns a PC-Ultra and an EP-600.

Hope this helps to clear things up a bit ! :)
 

AngelEyes

Distinguished Member
Hi Craig,

Thanks, I wasn't trying to imply anything about the test, just curious as to the decisions you have made and as you say they certainly left no room for 'guessing'.

I hope I get the opportunity to participate a blind test sometime in the future. Unfortunately I don't have a dedicated HT room so hosting one would be a problem. However if anyone offers I don't mind dragging my sub along. :cool:
 

jakeman

Standard Member
Being a participant, I can say Craig conducted one of the better listening tests I have ever attended. Besides being very careful with hiding and calibrating the subs, the listeners at Craigs instruction also kept their thoughts to themselves after every listening session to avoid biasing others. Each listener then spent 15 minutes individually contemplating what was heard and writing it down. Craig had prepared listening criteria sheets which helped everyone reflect and organize their impressions. All in all very professionally and scientifically done right down to the big surprise that we were listening to 2 subs and not 4 as we originally thought. What a twist! Craig's planning would have made a pioneer like Floyd Toole proud. :thumbsup:
 
C

craigsub

Guest
AngelEyes said:
Hi Craig,

Thanks, I wasn't trying to imply anything about the test, just curious as to the decisions you have made and as you say they certainly left no room for 'guessing'.

I hope I get the opportunity to participate a blind test sometime in the future. Unfortunately I don't have a dedicated HT room so hosting one would be a problem. However if anyone offers I don't mind dragging my sub along. :cool:

AngelEyes, Your questions were excellent - No worries there ! As jakeman said in the above post, when doing a blind test, make sure you set the test up so that ONLY the ears are the determining factor. The other point is that you should not care WHO wins, or even if there IS a winner.
 

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