For a long time we've been talking about doing compartive tests from driver to driver in car. So what we did is take / construct each vented box we suggest for each driver.

Test Goals -
To test FR of each individual driver at a reference level.

The reference level we selected was 110dB. We selected this reference level becuase for one reason we are using a TL Sensor. So realistically on many manufactures measurement tools we're dealing with 120dB reference by comparison. However we are setting the listening reference level at 110dB on the termlab sensor.

With that said this reference level was also selected becuase for daily listening one shouldn't be planning on listening beyond this for extended periods of time. 110dB at 20Hz in car is quite loud (imo).

The test equipment -
Europower 2400 - 2400 watts of headroom. allows us to control input voltage.
B&K Frequency generator - allows us to control frequency very specifically.
03 VW GTI - All tests are done in car, in the same vehicle, in the boxes we recommend on the site. Same tuning, etc etc.
Termlab USB Sensor on Windows 2000. This is what we've been waiting to do.

Criteria -
All of these tests were done 'legal' style measurements in the vehicle. Sensor on the window, doors closed, etc etc. No tom foolery or trickery, no one was in the car during any of the tests and we were outside at all times.

Enclosures -
Exact same boxes we recommend on the site
9Kv.2 - same box
11Kv.2 / 11Ov.2 - tested in same box / same tuning for consistency
13Kv.2 / 13Ov.2 - tested in same box / same tuning for consistency
13Kv.2 / 16Ov.2 - tested in same box / same tuning for consistency

FR Tests - This test was to determine Frequency response at reference level. This is precisely what magazines do. EQ, and get their FR with a varance. We selected a .5dB varaince. With EQ the results were extremely extremely consistent.

We also selected our cut off frequency on the top end at 100Hz. The reason for this. It seemed stupid and trivial to test them in vented boxes beyond that. I can't remember a single person using our drivers above that, or asking if they should. The suggested crossover point in all of these boxes is 80Hz or below.

Results - Frequency Response.
9Kv.2 - 10 - 100Hz w/ .5dB or less variation
11Kv.2 - 10 - 100Hz w/ .5dB or less variation
13Kv.2 - 10 - 100Hz w/ .5dB or less variation
16Kv.2 - 10 - 100Hz w/ .5dB or less variation
11Ov.2 - 10 - 100Hz w/ .5dB or less variation
13Ov.2 - 10 - 100Hz w/ .5dB or less variation
16Ov.2 - 10 - 100Hz w/ .5dB or less variation

Keep in mind every single one of these woofers at 10Hz exceded our 110dB cap by a good deal. So this is by no means a peak SPL measurement. This is FR measurement for in car response with these enclosures at listening levels. 110dB on the termlab.

- disclaimer. we do not recommend extended listening of any of these subwoofers for extended periods of time at 110dB -

Average SPL measurements. These measurements are done at each woofer at roughly 70-80% of excursion. We didn't find it necessary to push each woofer to it's extreme limits. This is meant as a basis for comparison between each woofers average output.

Results - Average In-Car SPL

9Kv.2 - 10 - 100Hz - 120.56dB

11Kv.2 - 10 - 100Hz - 121.14dB
11Ov.2 - 10 - 100Hz - 122.34dB

13Kv.2 - 10 - 100Hz - 123.85dB
13Ov.2 - 10 - 100Hz - 126.04dB

16Kv.2 - 10 - 100Hz - 123.92dB
16Ov.2 - 10 - 100Hz - 130.15dB

Peak SPL measurements. These were done in the same enclosures used for every woofer in the test as done above, the same boxes we reccomend on the site. These are NOT SPL oriented boxes. All done on the TL, legal style measurements. These show you a GREAT reference for peak output in the test vehicle in our recommended vented boxes. I say again, these are not SPL vented boxes. The 12" box is a 27Hz tune for example.

Results - Peak In-Car SPL

9Kv.2 - 10 - 100Hz - 134dB @ 52Hz

11Kv.2 - 10 - 100Hz - 136.3 @ 52Hz
11Ov.2 - 10 - 100Hz - 137.9 @ 48Hz

13Kv.2 - 10 - 100Hz - 140.1 @ 50Hz
13Ov.2 - 10 - 100Hz - 141.9 @ 54Hz

16Kv.2 - 10 - 100Hz - 142.5 @ 48Hz
16Ov.2 - 10 - 100Hz - 145.00 @ 54Hz

These Peak SPL measurements were done independantly of the avg. spl measurements and each driver was driven in it's recommended enclosure at full excursion.

If you have any questions please feel free to ask.

 

that's excellent info. Have you guys considered doing something like this for sealed enclosures?

 

Sealed tests! Sealed tests!

(I'm a SQ guy)

 

You can get SQ from a vented box that's built properly. If you really were a SQ guy you'd know that.

 

exactly!

 

And what's the point of a vented box if all you want is SQ?

 

ding ding ding

 

Umm if it's tuned properly, a sub in a vented box will get louder than in a sealed box. Sealed boxes are pretty inefficient, but are easier to build and there's basically no tuning involved.

 

Once again, I'm all about SQ. I don't care if it's loud.

 

 

I only posted because I know mandros IS doing sealed tests.... so

 

If you have ever used any subwoofer enclosure design program you would know that a properly vented box yeilds a much smoother response curve which gives better SQ.

 

Working on that...not sure if they were done yet or not...I know we needed some boxes first ;)

Regarding sealed vs. ported...all these boxes are tuned around 28-30Hz...definitely SQ set up boxes.

And yes...it is very much possible to use a ported box in an SQ app...really it just depends on the music you listen to.

Me = a bit of everything w/ some drum and bass thrown in. Ported would get killed on the 15Hz note so I just stay sealed.

 

im ported all the way. since im not a sper audiophile i can lose a lil sq and not mind.