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Discussion Starter #1 (Edited)
Full report attached as PDF.

I borrowed this driver from a friend who has yet to use it. The driver was tested on the same baffle all drivers I test are. Luckily, the baffle accommodates up to 10" drivers.

The data you see is a bit perplexing when compared to mfg "linear xmax" values, but IMO, the fact that Cms is the most limiting value could be an indication of it needing a small enclosure; which logic tells you anyway given the fact that it's a small sub designed for a small enclosure. Additionally, the forward offset is so great, it surely must be a design characteristic (at least, I'd hope) and I'm curious what the reason for this could be. I'd like to build a small box, mfg recommended size, to see what the effect on the results are. But, since all my testing is done in dipole fashion I must present this data in the same way I do all my other tests. So, my warning with this data is this: I do not know of any other 'shallow mount' woofers being tested with the Klippel and therefore, AFAIK, this is the first type of this kind of woofer to have results published for all to see. Let's try to consider the implications of the data before jumping to any immediate conclusions. IOW, let's discuss rather than brand.

Also, I want to note two things about this test:
  1. First off, I was unable to resolve Bl. I pushed this driver as far as I feel comfortable doing. In fact, I pushed the suspension as hard as the Klippel would let me (25% protection on Cms) in three tests and never was able to resolve Bl.
  2. Note the laxed distortion limiting percentages. I'm using these values as a 20% overall distortion set; which I've seen done in VC for subwoofers and I've discussed with Patrick. Providing overall 10% distortion parameters (82% Bl, 75% Cmin) is as easy as punching these numbers in to the test file so I can provide that should you guys feel that data set is more applicable.
Link to Driver:
http://www.madisoundspeakerstore.com/approx-10-subwoofers/sb-acoustics-sw26dac76-4-shallow-10-subwoofer-4-ohm/

Measured T/S Parameters:
  • Re = 3.1674 ohms
  • Fs = 24.1651 Hz
  • Zmax = 42.4726 ohms
  • Qes = 0.5582
  • Qms = 6.9271
  • Qts = 0.5166
  • Le = 0.7881 mH (at 1 kHz)
  • Diam = 207.0100 mm ( 8.1500 in )
  • Sd =33656.7797 mm^2( 52.1681 in^2)
  • Vas = 54.6781 L ( 1.9309 ft^3)
  • BL = 10.4873 N/A
  • Mms = 127.6607 g
  • Cms = 339.7849 uM/N
  • Kms = 2943.0386 N/M
  • Rms = 2.7982 R mechanical
  • Efficiency = 0.1299 %
  • Sensitivity= 83.1532 dB @1W/1m
  • Sensitivity= 87.1771 dB @2.83Vrms/1m
Klippel Linear Xmax Values:
  • X Bl @ Bl min=70% >8.5 mm
  • X C @ C min=50% 6.6 mm

Sample Data:

















Pictures from phone:
 

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Makes sense to me that a shallow sub will use suspension compliance to limit excursion. This way driver damage is prevented. This is a fantastic driver in all other respects. I would think most shallow subs will test this way suspension wise. The exception would maybe be Alpine and SI. SI has the XBL motor to prevent overexcursion at the limit and Alpine has the motor going through the spider to make more efficient use of a shallow basket.
 

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Makes sense to me that a shallow sub will use suspension compliance to limit excursion. This way driver damage is prevented. This is a fantastic driver in all other respects. I would think most shallow subs will test this way suspension wise. The exception would maybe be Alpine and SI. SI has the XBL motor to prevent overexcursion at the limit and Alpine has the motor going through the spider to make more efficient use of a shallow basket.
Good to know... Thanks for the explanation. Still learning how to interpret graphs. :p

What can you tell us about the BL curve? Thanks

Kelvin
 

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Any reason you went with the 4 ohm over the 8 ohm version of this sub? The 8 ohm has twice as much Bl and can work in much smaller boxes.


Edit.. just saw you said you borrowed this from someone. Though I remember you saying you were looking to experiment with a shallow sub.
 

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Good to know... Thanks for the explanation. Still learning how to interpret graphs. :p

What can you tell us about the BL curve? Thanks

Kelvin
The motor on this sub is a beast, especially in the subset of shallow units. It looks like it has at least 13mm stroke at the .75 point down on the BL curve. The asymmetry is not very good but in the context of %changes it's not really worrying. Another way to check that the motor is very low distortion is to look at the plot where it lists all three components, inductance, suspension and motor. Suspension is by far the most limiting.

Ideally I'd like to see harmonic distortion plots as well for these shallow subs. Some of the "tricks" that are used to get a low profile might result in resonances that are otherwise unseen in a Klippel test.

For people in the market for a shallow sub I'd say this might have the goods to take down the Type R.
 

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The motor on this sub is a beast, especially in the subset of shallow units. It looks like it has at least 13mm stroke at the .75 point down on the BL curve. The asymmetry is not very good but in the context of %changes it's not really worrying. Another way to check that the motor is very low distortion is to look at the plot where it lists all three components, inductance, suspension and motor. Suspension is by far the most limiting.

Ideally I'd like to see harmonic distortion plots as well for these shallow subs. Some of the "tricks" that are used to get a low profile might result in resonances that are otherwise unseen in a Klippel test.

For people in the market for a shallow sub I'd say this might have the goods to take down the Type R.
Thanks for the explanation... Now I need to go back to previous tests and look for similarities :D

For your info, I got a reply (finally!!!) from RE Audio regarding my SL10 shallow sub:
Kelvin, Below is the information that I can provide as some of what you are asking is trade secrets.

Coil is 2.5 inch diameter

The spider less design was to maintain an extremely low mounting depth and still have a large amount of excursion for a shallow woofer.

As for the Klippel measurements they were lost in a computer crash before a back-up could be made. (as if :rolleyes:)
Too bad I don't live in the US or I would have sent mine for Klippel...

Kelvin
 

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It's all the spider tricks that are worrisome. Traditional designs have been improved on for decades with higher mounting points, basket venting under the spider, progressive design etc. The new technology has to overcome all of this in a much smaller, less vented package. We don't just need a Klippel we need HD tests for sure.

Well the Klippel was not made in the U.S. and it certainly isn't unique. You may have to spend a lot more out of the U.S. to get one tested that's almost for sure. :(
 
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