Tectonic Elements TEBM35C10-4 Miniature BMR® Driver

IMG_3960 IMG_3962I was recently browsing the Parts-Express website and came upon some products from Tectonic Elements that I thought were interesting: the BMR series speakers.  BMR stands for Balanced Mode Radiator.  Some words from their website:

Tectonic Elements has developed a methodology for controlling modal bending wave activity enabling pistonic action and surface excitation to be combined in a single transducer or driver. This results in a small form-factor speaker drive that delivers uncanny sound quality due to its wide dispersion of sound, and full range response. Listeners have described itʼs audio fidelity as ʻlifelikeʼ and ʻunencumbered by the attributes of speaker mechanicsʼ. Tectonic Elements’ family of products utilising this patented technology is called BMR® and are set to transform listening pleasure from small format, low-cost loudspeakers.

 

Paint me intrigued!  A few google search results later and I had found some really positive words for their 3 inch full range driver found here.

A few minutes later I found that Tectonic Elements was releasing a 2 inch driver: the TEBM35C10-4.  The data sheet looked quite impressive.  Here’s a little blurb from their site:

The TEBM35C10-4 BMR® is an audio drive unit with an extended frequency response and extremely wide directivity. It combines the benefits of Tectonic Elements bending-wave technology and pistonic modes of operation. The small form-factor is ideally suited for compact products that require a full-range drive unit, room filling sound and a high performance acoustic solution.

I couldn’t find these available to purchase so I contacted the company.  What a great bunch… they were happy to send me a couple samples of their TEBM35C10-4 driver.  So, here we are… let’s get to testing!

Size wise, these are small.  Here’s a few quick dimensions:

  • Outer Diameter = 52mm (54mm counting the mounting tabs)
  • Mounting Depth = 23mm (surface mounted), 25.1 (flush mounted)

 

Impedance and Thiele-Small Testing:

Results were obtained via Dayton’s DATS v2 using the added mass method.

  • Effective Diameter = 37.08 [mm]
  • Re = 4.181 [Ohms]
  • Fs = 146 [Hz]
  • Zm = 18.69 [Ohms]
  • BL = 2.134 [N/A]
  • Qms = 3.848
  • Qes = 1.109
  • Qts = 0.8608
  • Vas = 0.148 [liters]
  • Le(10k) = 0.07819 [mH]
  • dBSPL = 78.08 [1W/1m]
  • Ms = 1.316 [grams]
  • Cms = 0.903 [mm/N]

tectonics elements tebm35c10-4 impedance

Frequency Response:

The following response measurements were taken at 2.83v at 1 meter.  Nearfield response was merged with far-field at approximately 3khz.

The measurements were performed at 0, 15, 30, 45, and 60 degrees.

  • 0 = Black
  • 15 = Blue
  • 30 = Purple
  • 45 = Red
  • 60 = Green
FR without legend

2.83v/1m. 0, 15, 30, 45, 60 degrees.

Harmonic Distortion:

Distortion testing was done in the nearfield to emulate the following farfield responses:

90dB @ 1m:

HD @ 90dB96dB @ 1m:

HD @ 96dB

Here’s the same result above but with a pointer for the 3% THD mark:

hd @ 96dB with 3% pointer

 

Conclusion:

This driver has an incredible bandwidth for it’s size.  This driver literally fits in my palm yet should have no problems playing from 300-400hz (with a proper high-pass; listener dependent) all the way up to 20khz without issue.  Cone breakup is practically non-existant with only a hint of breakup at 18khz.  THD is very, very low given it’s size.  At 96dB output the 3% THD mark is about 300hz; Above 500hz the THD is <1%.  Use this with a high-pass filter and most shouldn’t have an issue crossing down to 400hz.  At 30 degrees off axis the response is down 3dB and at 60deg off axis the response is 7dB down at 10khz.  Those numbers are on par with some of my favorite 1 inch tweeters.  I’m very impressed.  Of course, all this comes at a cost and the cost here is: sensitivity.  On average this driver runs about 77dB at 2.83v/1m.  Bummer.  Compression testing would benefit me here but since I have nothing to A/B it against, I’m gonna let it stand.  Of course, a high-pass filter also remedies compression to a good degree and since I don’t expect someone listening to this driver at high output near Fs, I suspect compression issues will be fairly inconsequential.

Naturally people will compare this to the AuraSound 2″ driver (aka: the “whisper”).  While the whisper has approximately 4dB higher sensitivity on average, this driver has a lower Fs, low THD, and an excellent polar response.  I don’t believe the whisper can cover the same bandwidth as well as this particular Tectonic Elements driver can.

Price wise, we will have to wait and see.  Since this driver hasn’t been released yet there’s no definite way to know what the retail price will be.  However, based on their other products sold in the US by Parts-Express, I’d expect pricing to be somewhere in the $15-20 range.  If that holds true,

Array anyone?….I’d really be interested to see how these perform in an array.  Hopefully I’ll get the time to perform that kind of testing and I will definitely post the results if/when I do.

PS:  If you would like to help me keep up funds for testing, there’s a little ‘contribute’ button that goes through Paypal all the way at the bottom of every page.  Any little bit helps.

AudioFrog GB25 2.5″ Midrange


Up for test is AudioFrog’s GB25 2.5″ Midrange.  Pictures don’t do justice to the compactness of these drivers but here they are anyway…

IMG_3095 IMG_3096 IMG_3097

 

 

Small Signal Parameters

Results as measured via Dayton’s DATs measurement tool.  Which is a very little handy tool to have.  😉

  • f(s)= 162.80 Hz
  • R(e)= 2.36 Ohms
  • Z(max)= 18.39 Ohms
  • Q(ms)= 6.010
  • Q(es)= 0.885
  • Q(ts)= 0.771
  • V(as)= 0.225 liters (0.008 cubic feet)
  • L(e)= 0.34 mH
  • n(0)= 0.10 %
  • SPL= 82.29 1W/1m
  • M(ms)= 3.63 grams
  • C(ms)= 0.26 mm/N
  • BL= 3.15

gb25 impedance

 

Frequency Response

Frequency Response and the following Harmonic Distortion measurements were taken using Dayton’s OmniMic measurement system.  For this test, the driver was surface mounted (not flush mounted) on the baffle.  The backside of the driver cutout was chamfered to allow for the driver to ‘breathe’ better, as is often recommended for such small drivers.

The frequency response measurements below are on-axis (0 degrees) and off-axis (15, 30, 60 degrees), measured at 2.83v/1m.

GB25 0-60 2

 

 

Harmonic Distortion

The following HD graphs are done in the nearfield, emulating 90dB at 1 meter as well as 96dB and 102dB at 1 meter, respectively.

gb25 hd90 gb25 hd96 gb25 hd102

Thoughts

The impedance sweep results indicate an Fs of 162hz with a Qts of 0.771.  Vas is 0.008 cubic feet.  Pairing the Vas/Qts specs up, it’s seen that this driver has the capability te mounted free-air or in a very small enclosure.  Of course, a high-pass filter makes these points less important, but it is worth noting that if using a sealed enclosure it can be very, very small.

Frequency Response results indicate a very nice on/off-axis response symmetry.  On-axis, the results are very linear up until about 5kHz where beaming (where on/off axis response diverges) begins to increase.  That said, the typical modal issues above the beaming point are kept to a minimum with only a 5dB rise centered around ~8khz.  Compare this to other various drivers and you’ll find often in the case of a poorly damped cone, they will exhibit breakup issues resulting in peaks increasing above 10dB.  Additionally, this driver does a good job at minimizing this breakup off-axis as well.

The 102dB level Harmonic Distortion plot shows 1% THD is reached at ~300hz, whereas at lower levels (90dB) this 1% THD mark is reached at approximately 200hz.  Above these respective values/output levels the THD is typically below 0.50%.  Using a crossover at the recommended 200hz/12dB, the low frequency THD will be mitigated and rendered moot.  One area I like most about these results is regarding the cone breakup, which as noted above is kept incredibly minimal and spread out through a wider band rather than a single large peak.  Typically with a sharp breakup mode you see a correlating increase in 2nd order distortion.  With this particular driver the 5dB breakup mode at ~8khz results in no significant increase in distortion and even at 102dB, the THD at 8khz is nearly 0.30%.

For those looking to use this as a dedicated midrange in an active three-way system, I’d  say this driver can easily be crossed in the 250-300hz region for high-output when a crossover and 2nd order or greater slope is used (or, if more moderate output is the norm for you, 200hz would be conceivable but I personally err on the side that likes to limit excursion).  Given my tendencies to want to listen at 95dB+ levels (fullrange) from the seated position, I’d personally expect to run this driver from 300hz – 6/7khz to minimize excursion on the low end while permitting better lining up a tweeter to the top end. Given the off-axis performance compared to the on-axis performance I could see running this higher than this but the crossover in the ‘ideal’ world may prove to be a bit trickier as you get further away from the beaming point and beyond the breakup point.

Bottom Line:  These are some really nice results from a very small driver, which is the important factor to me, personally.  Simply put, these drivers provide a lot of usable bandwidth for a very small footprint.

PS:  If you would like to help me keep up funds for testing, there’s a little ‘contribute’ button that goes through Paypal all the way at the bottom of every page.  Any little bit helps.

ScanSpeak Revelator 12M/4631-G00 4.5″ Midrange

 

 

Up for test is the Scan-Speak Revelator 12M/4631G-00 4.5″ Midrange.
Product specs can be found here.

IMG_2490IMG_2485IMG_2484IMG_2483


Small Signal Parameters and Impedance

Results as measured via Dayton’s DATs measurement tool.  Which is a very little handy tool to have.  😉

  • f(s)= 84.11 Hz
  • R(e)= 3.68 Ohms
  • Z(max)= 35.95 Ohms
  • Q(ms)= 5.242
  • Q(es)= 0.598
  • Q(ts)= 0.536
  • V(as)= 2.159 liters (0.076 cubic feet)
  • L(e)= 0.32 mH
  • n(0)= 0.20 %
  • SPL= 85.21 1W/1m
  • M(ms)= 6.18 grams
  • C(ms)= 0.58 mm/N
  • BL= 4.48

12m impedance

Frequency Response

Frequency Response and the following Harmonic Distortion measurements were taken using Dayton’s OmniMic measurement system.

The frequency response measurements below are on-axis (0 degrees) and off-axis (15, 30, 60 degrees), measured at 2.83v/1m.

12m FR

Harmonic Distortion Testing

Legend:

Maroon – Fundamental

Blue – THD

Red – 2nd Order Distortion

Pink – 3rd Order Distortion

Green – 4th order

Teal – 5th order

Testing done in the nearfield to emulate 90dB, 96dB, and 102dB output at 1 meter.

12m HD9012m HD9612m hd102


Impressions/Results

The frequency response linearity is really quite nice, maintaining a fairly flat profile out to 10khz.  The average sensitivity at 2.83v/1m is about 88dB and the response on-axis fluctuates only by about -3dB with no severe cone breakup issues outside the typical passband of beaming (approximately 2khz).  The off-axis response is very nice, maintaining a smooth transition much further than anyone is likely to cross this driver.  At 30 degrees off-axis at 5kHz the output is down about 4dB and at 60 degrees it is down about 12dB.

At 102dB output, distortion reaches 3% THD below ~120hz.  Distortion dips below 1% THD at about 220hz and dips down to 0.50% at about 400hz before a rise in THD begins around 700hz, reaching a maximum THD level of 1.80% at approximately 1.73kHz.

PS:  If you would like to help me keep up funds for testing additional drivers, there’s a little ‘contribute’ button that goes through Paypal all the way at the bottom of every page.  Any little bit helps.

Scan-Speak Discovery 10F/8414G10 “Fullrange”


Up for test is Scan’s newer edition to their 10F lineage: The 10F/8414G10.  This features a smaller neo magnet than it’s predecessors, making it an easier fit for tighter install applications.  I tested one of those models a couple years ago, and the data can be viewed here.

 

IMG_2237 IMG_2240 IMG_2239

 

 

Small Signal Parameters

Results as measured via Dayton’s DATs measurement tool.  Which is a very little handy tool to have.  😉

  • f(s)= 133.20 Hz
  • R(e)= 5.73 Ohms
  • Z(max)= 18.36 Ohms
  • Q(ms)= 2.251
  • Q(es)= 1.022
  • Q(ts)= 0.703
  • V(as)= 1.219 liters (0.043 cubic feet)
  • L(e)= 0.55 mH
  • n(0)= 0.27 %
  • SPL= 86.39 1W/1m
  • M(ms)= 2.17 grams
  • C(ms)= 0.66 mm/N
  • BL= 3.19

10f_8414G10 impedance

Frequency Response

Frequency Response and the following Harmonic Distortion measurements were taken using Dayton’s OmniMic measurement system.

The frequency response measurements below are on-axis (0 degrees) and off-axis (15, 30, 60 degrees), measured at 2.83v/1m.

10f_8414G10 HD 0 15 30 60

 

Harmonic Distortion

The following HD graphs are done in the nearfield, emulating 90dB at 1 meter as well as 96dB at 1 meter, respectively.

10f_8414G10 HD 90db 10f_8414G10 HD 96db

 

 

Thoughts

Frequency Response:  This is pretty much cream of the crop stuff here.  Average sensitivity is approximately 85dB @ 2.83v/1m.  While not dead flat across the board, there is a high-shelf like boost above 2khz by about 3dB.  The response also trends upward on-axis.  At 30 degrees off-axis, this driver is practically flat out to 10khz.  The polar response (off-axis response relative to on-axis) is stellar.  Each axis of measure follows the same trend above the beaming point (which is determined by the diameter of the drive unit; in this case approximately 2khz) which is a sign of a very well damped cone exhibiting no modal issues to speak of until nearly 15khz.  This excellent polar response means a couple things: a) if you wanted to use this above the beaming point there will be no significant modal ringing or specifically harsh areas in the sound or b) if you plan to cross this to mate with a tweeter, keeping directivity at the crossover low this driver will not need a lot of ‘work’ at the crossover because outside of the typical crossover point I’d expect one to use here there are no aberrations in the response; just a general upward tilt to the response.

Harmonic Distortion:  The first thing worth noting is the 400hz high-Q peak in distortion.  At 96dB and 102dB equivalent output, this peaks to about 2-3% THD.  This is a resonance of some sort (possibly basket) evidenced by the fact the small blip in impedance lines up with this frequency.  Worth noting is this same peak in distortion appears in the my testing of the earlier 10f/4424g00 here.  Outside of that, the 3% THD limit is met on the low end at approximately 115hz.  The 1% THD line is above 300hz.  Above 600hz, distortion falls to under 0.50% THD throughout the rest of the frequency range.  Given the Fs of this drive unit and the THD, a realistic crossover range is in the 300-500hz region, depending on output levels and steepness of the crossover slope.

Comparing against the earlier 10f/4424g00 tested here: While FR looks very similar, THD is one area where this particular drive unit differs from the 10f/4424g00.  Comparing the THD of the two, you’ll see the distortion of the 10f/4424g00 unit increases above 1% to approximately 1.5% THD above about 1500hz where 2nd order distortion with that unit rose nearly 20dB.  The unit under test here keeps it’s low 2nd order distortion and is approximately 1% lower above 1500hz in comparison.

Test setup note:  The driver cutout was chamfered.  The driver was not flush-mounted; it was surface mounted.

PS:  If you would like to help me keep up funds for testing, there’s a little ‘contribute’ button that goes through Paypal all the way at the bottom of every page.  Any little bit helps.

AudioFrog GB40 4″ Midrange


Up for test is AudioFrog’s GB40 4″ Midrange.

The GB15 1.5″ tweeter was tested here.

It’s worth noting this review is based on mostly objective data.  These drivers – as well as the others from the AudioFrog GB series speakers – include a LOT of installation hardware to make installs quicker and easier.  I simply don’t have the time right now to really delve in to the facets of this here.

IMG_2217 IMG_2235 IMG_2233 IMG_2230 IMG_2226

 

 

Small Signal Parameters

Results as measured via Dayton’s DATs measurement tool.  Which is a very little handy tool to have.  😉

  • f(s)= 105.60 Hz
  • R(e)= 3.30 Ohms
  • Z(max)= 12.93 Ohms
  • Q(ms)= 2.654
  • Q(es)= 0.908
  • Q(ts)= 0.676
  • V(as)= 2.332 liters (0.082 cubic feet)
  • L(e)= 0.34 mH
  • n(0)= 0.29 %
  • SPL= 86.70 1W/1m
  • M(ms)= 4.81 grams
  • C(ms)= 0.47 mm/N
  • BL= 3.40

gb40 impedance

Frequency Response

Frequency Response and the following Harmonic Distortion measurements were taken using Dayton’s OmniMic measurement system.

The frequency response measurements below are on-axis (0 degrees) and off-axis (15, 30, 60 degrees), measured at 2.83v/1m.

gb40 fr 0 15 30 60

 

 

Harmonic Distortion

The following HD graphs are done in the nearfield, emulating 90dB at 1 meter as well as 96dB at 1 meter, respectively.

gb40 HD 90

gb40 HD 96

Thoughts

I’m going to have to make this quick…

FR indicates average sensitivity in the 85dB @ 2.83v/1m ballpark.  There’s an upward climb on-axis above 2khz, which is similar to what I measured with the JL Audio C5-400cm here and the ScanSpeak 10f I measured here.  Seems to indicate this may be better placed off-axis.  There’s a fairly small breakup at 6.7kHz that doesn’t bother me much, but does show up in all axes.  That said, this peaking is about 2 octaves above the nominal low-pass crossover and so benign it will be mitigated by the crossover anyway.

The THD at 96dB overall is quite low, though there’s an anomaly that shows up around 400hz.  I’m not sure what this could be, though it’s worth noting I saw the same issue with the Scanspeak 10f I measured a couple years back.  This doesn’t show up in any other of my measurements, which indicates that it’s not the measurement setup itself.  Not sure what this could be, exactly, but it’s interesting that this occurs with both these 4″ drivers. Outside of that issue, the THD measured at 96dB breaks down as follows: 3% THD is met at approximately 100hz.  At 200hz the THD measured is approximately 1.25%.  At 300hz the THD is approximately 0.60% and above 500hz the THD is below 0.50% and as low as 0.30% in some places.  Very good.

Overall: Given the upper frequency crossover is determined by the beaming point, with a 4″ driver you can expect to cross this driver on the high end at about 3khz (give or take depending on the slope).  The low end crossover is typically driven by the amount of distortion you get.  I’d say, if you pay attention to the trend (and ignore the 400hz concern) the appropriate crossover for this driver would be in the 200-250hz ballpark which would provide you plenty of output at low distortion.  Also this provides the ability to cross this lower than I typically recommend for the ScanSpeak 10f (one of my go-to suggestions). The mid 80’s sensitivity is likely due to the tradeoff of low frequency extension.  In other words, if the sensitivity were higher, distortion would be higher, lower in frequency meaning you may have to cross at 300hz rather than 200hz to achieve the same level of THD.

Speaking of the 10f comparison, the below pictures show the difference in size between the newer, smaller neo magnet version of the 10f (this one):

IMG_2218 IMG_2219

PS:  If you would like to help me keep up funds for testing, there’s a little ‘contribute’ button that goes through Paypal all the way at the bottom of every page.  Any little bit helps.

SB Acoustics’ Satori MW13P-4 5″ Mid


Up for test is a fairly new driver in SB Acoustics’ ‘Satori’ lineup: MW13P-4 5″ Mid(woofer/range).  At the time of this posting (02/26/15) this driver can be purchased from Madisound for about $155/each.  I’ve got a new install that calls for a 5″ midrange and I thought this would be worth a shot.  So, let’s check it out.

Let’s start this out by looking at this work of art…

IMG_2194 IMG_2196 IMG_2200 IMG_2201 IMG_2202

 

 

Small Signal Parameters

Results as measured via Dayton’s DATs measurement tool.  Which is a very little handy tool to have.  😉

  • f(s)= 48.45 Hz
  • R(e)= 4.16 Ohms
  • Z(max)= 38.69 Ohms
  • Q(ms)= 3.475
  • Q(es)= 0.419
  • Q(ts)= 0.374
  • V(as)= 12.410 liters (0.438 cubic feet)
  • L(e)= 0.46 mH
  • n(0)= 0.32 %
  • SPL= 87.17 1W/1m
  • M(ms)= 7.18 grams
  • C(ms)= 1.50 mm/N
  • BL= 4.66

Satori MW13P-4 impedance

 

 

Frequency Response

Frequency Response and the following Harmonic Distortion measurements were taken using Dayton’s OmniMic measurement system.

The frequency response measurements below are on-axis (0 degrees) and off-axis (15, 30, 60 degrees), measured at 2.83v/1m.

Satori MW13P-4 FR 0 15 30 60

Harmonic Distortion

Legend:

Maroon – Fundamental

Blue – THD

Red – 2nd Order Distortion

Pink – 3rd Order Distortion

Green – 4th order

Teal – 5th order

Testing done in the nearfield to emulate 90dB, 96dB, and finally 102dB output (in order):

Satori MW13P-4 HD 90dB Satori MW13P-4 HD 96dB Satori MW13P-4 HD 102dB

Thoughts

Frequency Response: As you can see above, there is about a 5dB rise in response beginning at about 1.5khz extending through the rest of the response in conjunction with typical modal issues.  It’s worth noting the ScanSpeak 15m exhibits the same rise, though, a bit earlier in frequency.  You can see the spec sheet here.  Additionally, ScanSpeak’s 15w exhibits very similar FR bump, as seen in the spec sheet here.  Comparing these two, you can see there are actually a lot of similarities in the FR between the Scan 15w and this 5″ Satori.  While the FR isn’t ruler flat, this rise occurs at a point where beaming has occurred and therefore most likely would be mitigated by a crossover point that allows a wider dispersion pattern to match up with a tweeter that is ‘omni’ directional at it’s low end.

The 8khz mode is about 10dB higher than the response at 2khz and shows up off-axis in each increment.  This shouldn’t be a real issue if this driver is crossed over at/before the beaming point, but if you were to try to eek extra performance out of this (though, I don’t advise it), either need a notch filter or a very steep crossover slope should be used to avoid the audible sibilance and brightness caused by this modal issue.

Harmonic Distortion: The HD looks VERY good.  Even at 102dB @ 1/2m equivalent the THD above 150hz is less than 0.30% for the most part which is still EXTREMELY low distortion for this high of SPL.  The separation between 2nd and 3rd order distortion at this output has about a 15dB delta above 300hz which is very nice.  Overall, some top-shelf distortion values.

Bottom line: Used as a midrange crossed above 200hz/LR2 and below 2khz/LR2 I’d say this is a stellar driver.  If you wanted to cross lower, I’d say 150hz is feasible with a steeper crossover.  You could get away with a lower crossover point but I personally prefer to go with larger drivers and cross high (relatively speaking) when I can.  On the high end, I would say that the 2-3khz region would be the max I’d go for reasons mentioned before.

Subjectively I can say that I’ve been using these in my car for the past couple weeks and have been VERY impressed with them.  I actually prefer them over the Scan 12m, and the Scan 15m/15w … but I’m basing these impressions on aural memory which isn’t great, so take that for what it’s worth.

As an aside… these things are just plain gorgeous!

For what it’s worth, Zaph tested the 6″ Satori some time ago and it had quite good results. This 5″ version emulates that.

Here is a link to download the 30 degree FRD and ZMA data.

 

PS:  If you would like to help me keep up funds for testing, there’s a little ‘contribute’ button that goes through Paypal all the way at the bottom of every page.  Any little bit helps.. heck, $3 buys me painter’s tape to help seal any small gaps in the baffle/blank interface.  😀

PHD FB 4.1 Midbass

PHD FB 4.1 Midbass Testing

Note:  Though these speakers are called ‘midbass’, I think their size and parameters lends them much more to a midrange use.

A set of these PHD speakers was loaned to me last year to test and I’m finally getting around to doing so.  While PHD is a 20-year old company, their presence hasn’t been really known (at least in my past 5-6 years in the car audio hobby) until the past couple years.  Given that, there’s very little actual testing on any of the PHD products that I’ve seen, and I hope to help change that.

Product info can be found at PHD’s website here.

IMG_8373IMG_8370

 

Small Signal Parameters:

Electrical Parameters
Re 3.32 Ohm electrical voice coil resistance at DC
Le 0.181 mH frequency independent part of voice coil inductance
L2 0.257 mH para-inductance of voice coil
R2 3.79 Ohm electrical resistance due to eddy current losses
Cmes 319 µF electrical capacitance representing moving mass
Lces 6.21 mH electrical inductance representing driver compliance
Res 28.71 Ohm resistance due to mechanical losses
fs 113 Hz driver resonance frequency
——————
fm 72.9 Hz resonance frequency of driver with additional mass
Mechanical Parameters
(using add. mass)
Mms 5.335 g mechanical mass of driver diaphragm assembly including air load and voice coil
Mmd (Sd) 4.933 g mechanical mass of voice coil and diaphragm without air load
Rms 0.582 kg/s mechanical resistance of  total-driver losses
Cms 0.371 mm/N mechanical compliance of driver suspension
Kms 2.69 N/mm mechanical stiffness of driver suspension
Bl 4.088 N/A force factor (Bl product)
Loss factors
Qtp 0.677 total Q-factor considering all losses
Qms 6.51 mechanical Q-factor of driver in free air considering Rms only
Qes 0.753 electrical Q-factor of driver in free air considering Re only
Qts 0.675 total Q-factor considering Re and Rms only
Other Parameters
Vas 1.3283 l equivalent air volume of suspension
n0 0.245 % reference efficiency (2 pi-radiation using Re)
Lm 86.09 dB characteristic sound pressure level (SPL at 1m for 1W @ Re)
Lnom 86.9 dB nominal sensitivity (SPL at 1m for 1W @ Zn)
Sd 50.27 cm² diaphragm area

fb 4.1 kms impedance

Large Signal Parameters:

 

Displacement Limits thresholds can be changed in Processing property page
X Bl @ Bl min=82% 1.4 mm Displacement limit due to force factor variation
X C @ C min=75% 2.6 mm Displacement limit due to compliance variation
X L @ Z max=10 % 1.9 mm Displacement limit due to inductance variation
X d @ d2=10% 9.4 mm Displacement limit due to IM distortion (Doppler)
Asymmetry (IEC 62458)
Ak 6.41 % Stiffness asymmetry Ak(Xpeak)
Xsym 0.91 mm Symmetry point of Bl(x) at maximal excursion

fb 4.1 bl fb 4.1 bl symmetry fb 4.1 cms fb 4.1 kms symmetry fb 4.1 kms fb 4.1 l(x) fb 4.1 lx(i)

 

 

Frequency Response:

The below is FR measured at 2.83v/1m, 0, 15, 30, 45, and 60 degrees with the accompanying polar.  You can see I stitched NF and FF at approximately 400hz, as this is where they lined up best for all axes.  These are smoothed to 1/12 octave.

  • Black= 0 Degrees (on-axis)
  • Red = 30 Degrees
  • Green = 60 Degrees

FR @ 0 30 60 2.83v

Non-Linear Distortion:

Harmonic Distortion, measured at approximately 5 inches from the cone, SPL emulating 90dB @ 1m and 96dB @ 1m.

  • Blue = THD
  • Red = 2nd Order
  • Pink = 3rd Order
  • Green = 4th Order
  • Teal = 5th Order

90dB @ 1m equivalent:HD 90db

96dB @ 1m equivalent:

HD 96db

 

IMD at 90dB/1m.  F1=110hz, F2=880hz (-6dB from F1).

IMD 90db 110_880

IMD at 96dB/1m.  F1=110hz, F2=880hz (-6dB from F1).

IMD 96db 110_880

Airborne FR151B8-22F

The following test is for the Airborne FR151B8-22F which can be purchased from Solen here.  At the time of this test, the MSRP is approximately $69CAD ($67USD).

 

IMG_6401 IMG_6403 IMG_6404

 

Thiele-Small Parameters

Electrical Parameters
Re 6.27 Ohm electrical voice coil resistance at DC
Krm 0.0214 Ohm WRIGHT inductance model
Erm 0.5 WRIGHT inductance model
Kxm 0.0493 Ohm WRIGHT inductance model
Exm 0.39 WRIGHT inductance model
Cmes 353 µF electrical capacitance representing moving mass
Lces 26.44 mH electrical inductance representing driver compliance
Res 62.31 Ohm resistance due to mechanical losses
fs 52.1 Hz driver resonance frequency
——————
fm 32.6 Hz resonance frequency of driver with additional mass
Mechanical Parameters
(using add. mass)
Mms 9.59 g mechanical mass of driver diaphragm assembly including air load and voice coil
Mmd (Sd) 9.217 g mechanical mass of voice coil and diaphragm without air load
Rms 0.436 kg/s mechanical resistance of  total-driver losses
Cms 0.973 mm/N mechanical compliance of driver suspension
Kms 1.03 N/mm mechanical stiffness of driver suspension
Bl 5.212 N/A force factor (Bl product)
Loss factors
Qtp 0.695 total Q-factor considering all losses
Qms 7.2 mechanical Q-factor of driver in free air considering Rms only
Qes 0.725 electrical Q-factor of driver in free air considering Re only
Qts 0.659 total Q-factor considering Re and Rms only
Other Parameters
Vas 3.145 l equivalent air volume of suspension
n0 0.059 % reference efficiency (2 pi-radiation using Re)
Lm 79.91 dB characteristic sound pressure level (SPL at 1m for 1W @ Re)
Lnom Zn missing dB nominal sensitivity (SPL at 1m for 1W @ Zn)
rmse Z 4.83 % root-mean-square fitting error of driver impedance Z(f)
Series resistor 0 Ohm resistance of series resistor
Madd 15.34 g additional mass
Sd 47.78 cm² diaphragm area

Airborne FR151B8-22F Magnitude of electric impedance Z(f)

Large Signal Analysis

Displacement Limits thresholds can be changed in Processing property page
X Bl @ Bl min=82% 2.8 mm Displacement limit due to force factor variation
X C @ C min=75% 3.7 mm Displacement limit due to compliance variation
X L @ Z max=10 %            >4.6 mm Displacement limit due to inductance variation
X d @ d2=10% 20.2 mm Displacement limit due to IM distortion (Doppler)
Asymmetry (IEC 62458)
Ak -2.28 % Stiffness asymmetry Ak(Xpeak)
Xsym -1.23 mm Symmetry point of Bl(x) at maximal excursion

Airborne FR151B8-22F Force factor Bl (X) Airborne FR151B8-22FBl Symmetry Range Airborne FR151B8-22F Mechanical compliance Cms (X) Airborne FR151B8-22F Stiffness of suspension Kms (X) Airborne FR151B8-22F Kms Symmetry Range Airborne FR151B8-22F Electrical inductance L(X, I=0) Airborne FR151B8-22F Inductance over current L(X=0, I)

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.

Airborne FR151B8-22F 0 30 60

Harmonic Distortion at 96dB/1m

Airborne FR151B8-22F 96db HD

Fountek FR89EX

A brother of the FR88EX tested previously (click here), here’s the Fountek FR89EX test data.

fr89ex-4Stock photo courtesy of Madisound.

Comparison photo:

FR88EX vs FR89EX

 

Thiele-Small and Impedance Results

Electrical Parameters
 Re  3.61  Ohm  electrical voice coil resistance at DC
 Le  0.029  mH  frequency independent part of voice coil inductance
 L2  0.170  mH  para-inductance of voice coil
 R2  1.47  Ohm  electrical resistance due to eddy current losses
 Cmes  266  µF  electrical capacitance representing moving mass
 Lces  10.25  mH  electrical inductance representing driver compliance
 Res  8.32  Ohm  resistance due to mechanical losses
 fs  96.4  Hz  driver resonance frequency
 Mechanical Parameters
 (using test encl.)
 Mms  2.294  g  mechanical mass of driver diaphragm assembly including air load and voice coil
 Mmd (Sd)  2.213  g  mechanical mass of voice coil and diaphragm without air load
 Rms  1.035  kg/s  mechanical resistance of total-driver losses
 Cms  1.189  mm/N  mechanical compliance of driver suspension
 Kms  0.84  N/mm  mechanical stiffness of driver suspension
 Bl  2.936  N/A  force factor (Bl product)
 Loss factors
 Qtp  0.407  total Q-factor considering all losses
 Qms  1.342  mechanical Q-factor of driver in free air considering Rms only
 Qes  0.582  electrical Q-factor of driver in free air considering Re only
 Qts  0.406  total Q-factor considering Re and Rms only
Other Parameters
 Vas  1.2582  l  equivalent air volume of suspension
 n0  0.186  %  reference efficiency (2 pi-radiation using Re)
 Lm  84.89  dB  characteristic sound pressure level (SPL at 1m for 1W @ Re)
 Lnom  85.33  dB  nominal sensitivity (SPL at 1m for 1W @ Zn)
 Sd  27.34  cm²  diaphragm area

Fountek FR89EX impedance

 

Large Signal Analysis

Displacement Limits  thresholds can be changed in Processing property page
 X Bl @ Bl min=82%  >3.8  mm  Displacement limit due to force factor variation
 X C @ C min=75%  2.6  mm  Displacement limit due to compliance variation
 X L @ Z max=10 %  >3.8  mm  Displacement limit due to inductance variation
 X d @ d2=10%  10.7  mm  Displacement limit due to IM distortion (Doppler)

fr89ex img_Bl (X) fr89ex img_Bl Symmetry Range fr89ex img_Kms (X) fr89ex img_Kms Symmetry Range fr89ex img_Cmes (X) fr89ex img_L(X) fr89ex img_L(I) fr89ex img_Temperature_ Power fr89ex img_Distortion

 

Frequency Response

0, 30, and 60 degrees in the farfield at 1m, 2.83v input.  200hz-20khz.  1/24 Octave Resolution.

Fountek FR89EX 0 30 60

Harmonic Distortion

Note:  This test was performed in the farfield, and subsequent to environmental issues such as reflections and noise. Therefore, please disregard data below 200hz as I cannot guarantee it’s accuracy.

Fundamental + Harmonic distortion components (96dB1m) FR89EX Relative Harmonic distortion (96dB1m)

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Fountek FR88EX

Another popular choice for fullrange use, the Fountek FR88EX is tested and results provided below.  For data on the FR89EX click here.

fr88-exPicture courtesy of Madisound.

Thiele-Small and Impedance Test Results

Electrical Parameters
Re 6.43 Ohm electrical voice coil resistance at DC
Le 0.042 mH frequency independent part of voice coil inductance
L2 0.299 mH para-inductance of voice coil
R2 2.53 Ohm electrical resistance due to eddy current losses
Cmes 170 µF electrical capacitance representing moving mass
Lces 12.96 mH electrical inductance representing driver compliance
Res 23.69 Ohm resistance due to mechanical losses
fs 107.2 Hz driver resonance frequency
Mechanical Parameters
(using test encl.)
Mms 2.979 g mechanical mass of driver diaphragm assembly including air load and voice coil
Mmd (Sd) 2.898 g mechanical mass of voice coil and diaphragm without air load
Rms 0.739 kg/s mechanical resistance of  total-driver losses
Cms 0.74 mm/N mechanical compliance of driver suspension
Kms 1.35 N/mm mechanical stiffness of driver suspension
Bl 4.185 N/A force factor (Bl product)
Loss factors
Qtp 0.581 total Q-factor considering all losses
Qms 2.714 mechanical Q-factor of driver in free air considering Rms only
Qes 0.737 electrical Q-factor of driver in free air considering Re only
Qts 0.579 total Q-factor considering Re and Rms only
Other Parameters
Vas 0.7827 l equivalent air volume of suspension
n0 0.126 % reference efficiency (2 pi-radiation using Re)
Lm 83.2 dB characteristic sound pressure level (SPL at 1m for 1W @ Re)
Lnom 81.14 dB nominal sensitivity (SPL at 1m for 1W @ Zn)
Sd 27.34 cm² diaphragm area

fr88ex impedance

Large Signal Analysis from Klippel LSI Module

Displacement Limits thresholds can be changed in Processing property page
X Bl @ Bl min=82% >3.5 mm Displacement limit due to force factor variation
X C @ C min=75% 2.4 mm Displacement limit due to compliance variation
X L @ Z max=10 % >3.5 mm Displacement limit due to inductance variation
X d @ d2=10% 9.6 mm Displacement limit due to IM distortion (Doppler)

fr88ex img_Bl (X) fr88ex img_Bl Symmetry fr88ex Range fr88ex img_Kms (X) img_Kms Symmetry fr88ex Range fr88ex img_Cmes (X) fr88ex img_L(X) fr88ex img_L(I) fr88ex img_Distortion fr88ex img_Temperature_ Power

Frequency Response

On-Axis merged at approximately 500hz, representing 2.83v/1m.  1/24 octave scaling.

Fountek FR88EX 0 deg merged

Response comparison at 0, 30, and 60 degrees.  1/24 Octave resolution.

Fountek FR88EX Frequency Response 0 30 60

Harmonic Distortion

Note:  This test was performed in the farfield, and subsequent to environmental issues such as reflections and noise. Therefore, please disregard data below 200hz as I cannot guarantee it’s accuracy.

96dB/1m

Fundamental + Harmonic distortion components (96dB1m) Relative Harmonic distortion (96dB1m)

If you want to contribute to the site’s funds via Paypal in order to purchase more drivers and test equipment (ie: a high SPL mic for subwoofer testing), please click the contribute button at the bottom of this page.