Up for test is a Funkin Audio FASX-380 15″ Subwoofer.  The sub is a dual 4ohm voice coil, though for this test only one coil was connected.

Thiele-Small Parameters

Large Signal Analysis

The following test is for the Airborne FR124B8-19F which can be purchased from Solen here.  At the time of this test, the MSRP is approximately $51CAD ($50USD).

Thiele-Small Parameters

Large Signal Parameters

Frequency Response

The following measurement result is a result of merging nearfield response with farfield at 2.83v/1m to illustrate a standard 2.83v/1m measurement.

Harmonic Distortion at 96dB/1m

As a reviewer for hometheatershack.com, I just wrapped up testing on the Rythmik Audio F12G subwoofer and have posted the data here:

http://www.hometheatershack.com/forums/sub-zone-subwoofer-testing/66876-rythmik-audio-gr-research-f12g-direct-servo-subwoofer.html

In a nutshell, I was very impressed with with the linear excursion of the SW-12-04 subwoofer driver at just under 18mm.  At the current MSRP of $179 believe it to be a great value.  The subwoofer as a kit (enclosure, amp, and driver) perform very well and have some very nice features most other powered subs do not have.

- Erin

By now you’ve probably seen my testing of the Kef HTS3001SE and Q100 drive units.  I had read the next step in the Kef Uni-Q line are the drivers in the “R” series.  So, a fella let me borrow the 5 inch midrange drive unit from the R300 speaker to test.  The R300 comes with a separate woofer but I was not sent this.  The only way to obtain these drivers individually is to purchase the speakers they come with (such as the R300 or R500 speaker) and remove them.  Which brings up something worth noting.  I am testing these raw drivers as more or less for knowledge purposes.  These kind of tests tell us exactly what the basis for a speaker is (drive units + enclosure + circuit design).  If Kef is starting with a great drive unit then one can logically assume they have likewise extended efforts to use them as a speaker in a manner which reflects their ‘raw’ performance.  In other words, if the drive unit design is great, odds are so is the complete speaker it’s used in.  Now, let’s get on with it!

Like the Q100, this driver has a very large motor structure and basket.  For a midrange, this is a HUGE drive unit, relative to other mids I’ve used.  You’ll also notice the motor and frame are a bolt together design.  The spider is below the cone on a tier sitting above where conventional speakers’ spiders are.  The surround of this driver has a curved shape to it, I assume to help it act more like a waveguide as with the cone’s shape.  The voice coil diameter is roughly 45-47mm (I had to spitball this so please take it as only an estimate).  OD is approximately 130mm.  Surface area (minus the tweeter assembly/waveguide) is about 98.01cm².  Actual effective surface area, noting the moving portion of the driver’s cone is 25cm²; the tweeter housing/waveguide is roughly 49mm in diameter.

Tweeter Thiele-Small Parameters

I didn’t have much time to perform full T/S parameter measurements (Vas, Bl, Mms, etc) so I have only the most basic parameters posted below.

Woofer Thiele-Small Parameters

I didn’t have much time to perform full T/S parameter measurements (Vas, Bl, Mms, etc) so I have only the most basic parameters posted below.

Klippel LSI

Klippel LSI testing of this speaker has not yet been performed simply due to lack of time.  I do plan to perform this testing so check back here from time to time.

Tweeter Frequency Response

0, 30, and 60 degrees.  2.83v/1m; Nearfield & Farfield merged at 1800hz.

Woofer Frequency Response

0, 30, and 60 degrees.  2.83v/1m; Nearfield & Farfield merged at 500hz.

Tweeter Harmonic Distortion at 90dB/1m and 96dB/1m

Woofer Harmonic Distortion at 90dB/1m and 96dB/1m

Miscellaneous Testing

I took some time to do a bit of additional testing with this driver just for fun using REW software and my calibrated mic.

I used an active crossover with a 3khz/LR2 crossover point between the mid and tweeter.  I then measured the driver at 0, 30, 45, 60, and 90 degrees to see how the response of the driver with this crossover applied measures in all angles.  The results are overlaid below in 1/12 resolution.

NOTE:  SPL is not indicative of any particular test method.  I just applied power to the driver and tested in various axes.  In other words, this is NOT indicative of 1w/1m or 2.83v/1m test standards.  The following is for the sake of seeing the driver’s performance in all axes with a 3khz/LR2 crossover.

Now, averaged them together for a single plot average of all the above points:

Same result as above, but in 1/3 octave:

Another bit of testing I did was to see how the peak between 5-6khz could be tamed.  So, I applied some DSP correction and did a comparison.  The result below is a measurement of the raw woofer response vs the EQ’d response taken on axis (0 degrees).

This isn’t to say it’s needed.  It’s just something I did because I had some time and thought I’d share. 

I failed to save the results from the off-axis measurements with the DSP included, but suffice it to say, the EQ cuts added to tame this peak worked and were shown to have diminished greatly in the off-axis measurements as well as the on-axis measurement shown above.

Impulse Response Note

Being this is called a coincident driver and the benefit of these are they are supposed to emanate sound from the sound point, I measured the tweeter and midrange drive units separately and evaluated the arrival of the impulse response.  The two impulse response lined up to a ‘T’.  Unfortunately, I didn’t save this measurement because I simply forgot to before I had to shut down the computer so am unable to post the results.

Parting Thoughts

The benefit of having a coincident design is excellent.  I’ve toyed with a few here and there, though, I felt the companies’ never quite got it right.  So, when I first started testing the Kef drive units I didn’t expect much, to be honest.  However, the previous Kef Uni-Q units I’ve tested (HTS3001SE & Q100) have proven to be very well designed.  My results for the R300 drive unit show the same standard of performance.  I took the time to listen to these along with the Q100 speakers I have and must say that I am now sold on Kef’s coincident driver engineering.  I was extremely impressed by these (two) drive units’ performance in my listening tests.  People tend to get caught up in subjective ‘analysis’ whereas I fall in to a very objective analyzer category.  I tend to ignore subjective reviews in whole and often advise others to use them lightly, unless there is objective data to correlate.  This is why it’s rare I comment on the sound of a speaker/driver.  But, I can unequivocally say, after about 3 weeks of listening to these R-series mids and the Q100 speakers – against my coveted DIY speakers and countless other drive units – these truly are the best drive units I’ve laid ears on.  And, for the price, the Q100 speaker is what I would consider an excellent value for the critical listener on a real-world budget.  In fact, I intended to sell my Q100′s after testing the drive units but I have since decided to use the Q100′s as portable reference system.

A fellow on tech-talk sent me four of these drivers to test and check for consistency.  I normally don’t see the need but figured it’d be interesting so I obliged.

I tested each driver’s impedance, frequency response and relative harmonic distortion. I added each driver’s respective result to the same graph for comparison purpose.  I then chose one of the drivers to do further testing on.  So what we have is the typical suite of data plus unit-to-unit comparison data.  I hope you enjoy!

Driver Comparison Testing

Let’s first start with the comparison data. All four drivers were tested in the exact same fashion.  One was tested, then removed from the baffle and the next was added.  The mic never moved and all the impulse responses were windowed to the exact same time(s).  Therefore, the only variant in each test is the driver itself.

Impedance Comparison

As stated above, I received (4) of these drivers to test.  However, I didn’t sweep the first driver sample for impedance so there are only (3) samples in the impedance data.

Frequency Response Comparison

The comparison testing for FR & HD was done at one-half meter, with 2.83v input signal.  The results on the FR below were each attenuated 6dB in order to provide a normalized 2.83v/1meter response SPL.

This response is in the horizontal plane only.  I did not test repeatability in the vertical plane.

Harmonic Distortion Comparison

End of Comparison Testing….

———————————————————————————————————————————————

Single Driver Testing:  Sample 3

After completing the comparison testing above, I chose Sample 3 to test further as it seemed to have the better response in FR and HD.  Yes, this is cherry picking but you’ve seen the variance above.

Thiele-Small Parameters

Frequency Response: Horizontal Axis

Frequency Response: Vertical Axis

Harmonic Distortion (Horizontal Axis)

Note the response rises throughout.  Therefore, the SPL level used to determine 96dB/1m was based on the fundamental mean SPL from 300hz to 5khz.  This is the same as I do on all my tests, albeit with some more wiggle room here by a couple dB.  Overall, this is comparable to my other test results.

Cumulative Spectral Decay

End

Up for test is the Scan Speak Discover 10F midrange.  This driver features a neo magnet to keep its weight down.  Accompanied with the extremely small form factor, this is a top choice for many in car audio and home audio alike.  While this is noted as a 4″ midrange, seeing it in person makes it appear to be closer to the 3.5″ driver family relative to other 4 inch drivers.  This is a driver I often recommend for its price vs performance, though I’ve never gotten the chance to test one until now…

Small Signal Analysis

Large Signal Analysis with Klippel’s LSI Module

Frequency Response with Klippel’s TRF Module

Harmonic Distortion with Klippel’s TRF Module

The following is HD results at both 90dB/1m and 96dB/1m equivalent.

Cumulative Spectral Decay

Thoughts

As this is a pure midrange, the xmax values provided by LSI aren’t frightening.  If you want to cross low, there’s not a lot of displacement so it’s best to use this with a woofer and cross above 300hz.  Judging by the rolloff, toward an Fs of 136hz, you’ll likely need to EQ assist the response below 400hz. Another benefit of this driver is it doesn’t require a large enclosure.  My measured Vas is approximately 0.7L, and the lower Qts of 0.45 allows you to go a tad below the Vas value to reach a Qtc of 0.707.

The overall frequency response of this driver is pretty nice, maintaining a fairly flat response in what I would call two ‘sectors’ of response; divided by 1.5khz.  At this point, the response dips a bit and increases by about 3dB to 2khz where it is fairly flat.  I’ve never been one to propose using wideband or fullrange drivers due to the lack of top end response and typical varying response above the pistonic range (aka: tweeterless) but in this case, I think one would be OK to do so given the extension through 20khz and smooth, controlled off-axis response.  There are no major nodal issues to speak of here; it seems the nomex cone is doing a good job of keeping break up to a minimum.

In line with that, THD results suggest a crossover above 300hz.  The bump in HD around 400hz is a driver-borne result.  I tested it a couple times in a couple different manners to see if it showed up consistently and there is nothing in the setup that would be the cause.  3rd order HD is quite nice, staying well below the 1% threshold above 200hz.  Subsequent even and odd-order distortion is very low.

All in all, not the world’s best results but as a midrange in a 3-way system crossed above 300hz or (as high as 500hz) this makes a very fine driver.  If one wanted, they could build a very nice 2-way speaker with this as well and let this driver handle everything above 300-500hz.

I recently purchased a set of Kef HTS3001SE speakers with the sole intention of testing the raw drive units only.  You can view the data here.  I had no intentions on testing the speaker because my curiosity ended at the drive unit itself.  However, at the request of quite a few people, I have decided to go further and test the speaker itself, in the ‘Egg’ enclosure.  The Kef speaker comes with the rear port stuffed, and thus, the option to remove the stuffing from the port enabling the listener to use them in a sealed or ported fashion, depending on placement and preference.  The data below is broken up in to two sections to reflect this.

On with the results…

Sealed Option Testing

Impedance and Magnitude

Frequency Response at 0, 30, and 60 Degrees

2.83v/1m

Harmonic Distortion

Approximately 96dB/1m Equivalent.  Windowed to 200hz as measurement was taken at one-half meter.

Ported Option Testing

Impedance

Frequency Response at 0, 30, and 60 Degrees

Harmonic Distortion

I did not perform HD testing for the ported option.

Frequency Response Comparison of Sealed vs Ported Option

Thoughts

The average output is approximately 81dB at 2.83v/1m.  Below 400hz, there’s a rise in response to a 3dB peak at 150hz possibly tied to woofer Q+enclosure Q.  The frequency response above 200hz remains fairly neutral.  There is a 2dB bump in response from about 2khz to 4khz and a rise in response above 8khz with a peak of 4dB from nominal at 10khz.  A bit of EQ should be able to tame this easily.  Off-axis response at 30 degrees looks pretty well behaved.  Harmonic Distortion looks quite nice, staying under 1% above 200hz with a small bump at 6khz and a rise above 8khz in 2nd order.  3rd order distortion stays pretty above 1khz, though it rides closely along 2nd order below 1khz.  Overall, pretty nice speakers with an aesthetically pleasing exterior.  Given these are intended as ‘satellite’ home theater speakers, I think they’d make a good option for music and desktop speakers depending on the price you can snag them for and your relative use of the word “value”.