Blast from the past! SpeakerWorks/USD Audio A-6.0 Testing

I was loaned this set of SpeakerWorks/USD Audio A-6.0 horns by a friend some time ago and recently came across them when shuffling some things around in a closet.  Even though these are circa 1995 (maybe earlier), I thought it might still be fun to test them out for “old times sake” to recapture some nostalgia.  Because, heck, reminiscing is fun and we can learn a lot from old designs.

Before moving too far ahead, I would like to address this specific horn and application given it’s age.  I contacted USD Audio to see if they could provide any insight on the product.  Eric Holdaway was kind enough to respond with some vital information that is crucial to understanding the implications of the preceding test results:

They are “A” models with the fiberglass body which are really, really old.  These should only be used with the original supplied EQ and compensation circuits or comparable devices for them to perform at their best.

Eric also added:

It sure was fun to “invent” the HLCD’s in the car thing with my Dad (Roger), Brother (Pat) and Great friend R.E Greene. Our U.S. Patent was amazing to get and lock in that we had created an original idea. This and the A-periodic subwoofer enclosure were a thrill to create.

 

I have to thank Eric for being kind enough to provide some info on a product that has been obsolete for nearly 2 decades and understanding the desire to still want to learn and revisit some nostalgic items back when car audio sound quality competition was in it’s “heyday”.  As Eric noted, these were designed to be used with an EQ/Compensation circuit.  However, this was not provided so please understand that while these results show the performance of the raw horn… that’s exactly what you are getting; you are not seeing the results as they were intended to be used from the factory as the above mentioned circuit is not tested as part of the kit here.  The owner said he might have this circuit somewhere so this test may be revisited later and updated accordingly.

 

With that said, let’s get started…

IMG_3972 IMG_3967 IMG_3979 IMG_3982 IMG_3980

IMG_3978As you can tell, these horns were treated with CLD (constrained layer damping – commonly known as “dynamat”, etc).  This was popular among competitors as it was used to reduce the horn body from resonating at higher frequencies.

 

Measurement Information

This horn was measured free-air.  This was not measured in a car nor was any sort of baffle used to mimic the bottom half of a dash, as these would typically use in an install to ‘extend’ the horn’s effect in the vertical plane.  It was attached to a 6×6 beam and measured both horizontally and vertically from -90 to +90 degrees.  For Frequency Response measurements, a signal of 2.83v was fed to the driver with the mic placed at 1 meter distance from the horn mouth.

 

Impedance Sweep

Results provided are obtained via Dayton’s DATS v2.

  • f(s)= 1325 Hz
  • R(e)= 5.789 Ohms
  • Z(max)= 14.54 Ohms
  • Q(ms)= 4.164
  • Q(es)= 2.754
  • Q(ts)= 1.658
  • L(e)= 0.8925 mH

USD Horn impedance

Frequency Response – Horizontal

I measured the A-6.0 horizontally, with the magnet side facing upwards from -90 to +90 degrees.  My 0 Degree axis was dead on the straight side of the horn.  Positive (+) degree measurements were performed going from 0 degrees to 90 degrees to the flare-side of the horn.  Negative (-) degree measurements were done going from 0 degrees to 90 degrees to the straight-side of the horn.  The polar mapped image below gives further illustration to help make this clear.

The second and third image are simply the 0 to +90 and 0 to -90 degree measurements broken out for easier viewing. Following these are some ‘comparison’ images at varying axes (i.e.; +15 vs -15 degrees).  Read the legends.

Horizontal Polar

0 to 90 hz 0 to -90 hz

15 vs -15 hz 45 vs -45 hz

Frequency Response – Vertical

I measured the A-6.0 vertically, with the magnet side facing upwards from -90 to +90 degrees.  My 0 Degree axis was dead on the straight at the horn.  The “bottom” is referred to as the compression driver side.  Positive (+) degree measurements were performed going from 0 degrees to 90 degrees to the top side of the horn (CD facing down side).  Negative (-) degree measurements were done going from 0 degrees to 90 degrees to the bottom side of the horn.  The polar mapped image below gives further illustration to help make this clear.

The second image is the 0 to +90 degree (top side) measurements broken out for easier viewing.

Vertical Polars 2

Vertical "top"

Harmonic Distortion

The following was done in the nearfield simulating 98dB @ 1 meter (1khz reference).  Note: Input voltage was 2.83v.

HD 2.83v 98dB @ 1m equivalent

The follwoing was done in the nearfield simulating 104dB @ 1 meter (1khz reference):

HD 104dB @ 1m equivalent

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.

Q&A: Eric Stevens

Car audio has a rich history filled with industry and hobbyists alike.  People who have pushed the envelope with their installs, technology, products, and intelligence.  Their contributions will always be regarded in some fashion; whether it be sharing knowledge via a forum, sharing experiences in install tricks, creating new products to help us get closer to our goals of a great car audio system, or continuing to push the competition aspect of the hobby.  With the vast amount of knowledge available I asked some of my friends who many consider “heavy hitters” in the community a few fun questions to see how their different origins and histories influence their perspective on the hobby today.

 

1) What is your name/age/education/occupation?
Eric Stevens, 53, Founder of Image Dynamics and speaker engineer starting a new brand “Stevens Audio”.


Note:  This article discusses Eric’s new company Stevens Audio:

 

2) What are your top 5 favorite songs of all time?
Can’t narrow it to just 5. I love a lot of different music.

 

3) What is your favorite thing about car audio? What keeps you in the hobby?
 Getting lost in the music and sharing it with others. I love music and audio is what keeps me in it as well as its become way more than a hobby.

 

4) What was your first stereo system? What was your first real attempt at a sound quality system?
First real system was helping put a Concord tape deck and amp with Pyle 6940 in my friend’s 79 Camaro. First real attempt at a competition SQ system was in a 86 Toyota xtracab PU using Dynaudio 17W75 with Dynaudio D28 tweeters and Crunch 10″ subwoofers in an ported Isobaric configuration using Coustic amps and Audio Control processors.

 

5) What are your favorite car audio memories? Any funny/cool stories that really make you smile when you look back?
Favorite memory was at 1996 IASCA Finals where with Image Dynamics competitors we had huge success. Many funny things happened over the years from sneaking beer with David Rivera (Fishman) into a Soundquake event, to celebrating at Spring Break with a large group and consuming copious quantities of food and tequila.

 

6) Things have changed a great deal in 15 years, … even 5 years. What do you think is around the corner for the sound quality car audio scene?
I would like to see the IASCA and other competitions grow again.

 

CA&E - July 1993 - "Installations - Company Car"

CA&E – July 1993 – “Installations – Company Car”

 

The picture above is from Car Audio & Electronics’ July 1993 article “Installations – Company Car” featuring Eric’s famed 1993 Mercury Sable build with commentary from the man himself.  You can find the article here.



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.

Q&A: Steve Cook

Car audio has a rich history filled with industry and hobbyists alike.  People who have pushed the envelope with their installs, technology, products, and intelligence.  Their contributions will always be regarded in some fashion; whether it be sharing knowledge via a forum, sharing experiences in install tricks, creating new products to help us get closer to our goals of a great car audio system, or continuing to push the competition aspect of the hobby.  With the vast amount of knowledge available I asked some of my friends who many consider “heavy hitters” in the community a few fun questions to see how their different origins and histories influence their perspective on the hobby today.

 

1) What is your name/age/education/occupation?
Steve Cook , 40s , owner and custom installer at AudioX Inc Custom Car Audio in Florence, AL.

 

2) What are your top 5 favorite songs of all time?
“Little by little” by Robert Plant… and … wow this is hard.  I cannot possibly tell you my five favorite songs.  There’s way too many.  But I can give you five favorite artist instead:  Pink Floyd , Dire Straits/ Mark Knopfler, Keb mo, Beck, Van Halen.

 

3) What is your favorite thing about car audio? What keeps you in the hobby?
Favorite thing about car audio besides creating cool installations is just listening to music in the vehicle, creating an atmosphere, and a realistic soundstage.  That’s what keeps me going.  Searching for that perfect car audio bliss.

 

4) What was your first stereo system? What was your first real attempt at a sound quality system?
My first system was in my 79 Camaro.  I had an alpine tape deck hooked up to some flea market 6×9’s in the back deck and I sat in my car in the driveway and listened to it for hours.  I was 16 and thought it was the coolest thing ever. 

 

But how I got started in car audio is another story.  My friend in art school, his dad worked at StereoRama in St. Petersburg, Florida.  He had a Firebird with a 500 W Alpine system in it and my friend said we were going to go for a ride down the beach in his dad’s car.  So we jumped in and went for cruise down the beach.  He started playing Frank Zappa at volumes I never heard and clearness I’ve never heard before with 4 10 inch woofers in the back and Alpine mids and highs and amplifiers.  It was the most amazing thing I’ve ever heard.  A concert in the car.  Unbelievable to this day.  That is what started it all for me! I wanted that!

 

Then the SPL bug hit me and after seeing some of the world’s loudest vehicles compete with the crowds standing around them in awe, I wanted to be the world’s loudest.  After 4 years of competing in 2004 I won the Extreme Cup for the world’s loudest vehicle and then continued on breaking records until 2008 until I realized that this was very difficult and an extremely physical thing to do. Toting around a 22,000 pound van full of concrete, steel, batteries and equipment was getting very dangerous and not worth the hassle!  So I started up my SQ addiction. Then the goal to have the best sounding vehicle in the world was my only drive!  And to this day I still sit in my garage and listen to my stereo and tweak on it to gain that little bit extra sense of realism and perfection that I can only try to get out of it.

 

5) What are your favorite car audio memories? Any funny/cool stories that really make you smile when you look back?
(see above)

 

6) Things have changed a great deal in 15 years, … even 5 years. What do you think is around the corner for the sound quality car audio scene?
The biggest things that’s changed in car audio in the last 10 years is the power of the amplifiers has increased and the physical size has decreased, as well as digital processors are now available so you can fine-tune a vehicle like you could never do before.  You can almost use stock locations in the car and a DSP to get the same effect today as a rebuilt dash or some crazy install back in the day.  It’s amazing what you can do now with the technology and products we have compared to years ago.

Steve Cook hoisting the MECA Culbertson Cup won in 2009 (he has since won a couple more).

Back of Steve’s Avalanche circa 2010. It has since undergone a few versions.

 audiox

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.

Hybrid Audio L1 Pro R2 Ring Radiator Tweeters


Up for test is the Hybrid Audio L1 Pro R2 Ring Radiator Tweeter.

Information from the manufacturer can be found here: http://hybrid-audio.com/le/

IMG_2475 IMG_2474 IMG_2482

 

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)= 639.90 Hz
  • R(e)= 3.48 Ohms
  • Z(max)= 6.84 Ohms
  • Q(ms)= 1.641
  • Q(es)= 1.702
  • Q(ts)= 0.835
  • L(e)= 0.48 mH

l1pro imp

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.

l1pror2 FR

To get an idea of the off-axis response vs the on-axis (0 degrees) response, I normalized the above.  What you get is the relative output level of each axis vs the on-axis level.

l1pror2 normalized

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 and 96dB output at 1 meter.

l1pro r2 hd90l1pro r2 hd96

Impressions/Results

The Fs is measured at approximately 640hz.  To get an idea of what this means on the high-pass crossover, let’s evaluate the HD results.  At 96dB output the THD (blue) is 1.70% at 1khz.  The THD is less than 0.50% down to 1.8khz though there is a peak in THD of about 1.0% THD at 2.8kHz, which corresponds with the dip/peak shown in this region on the frequency response as well as a bump in the impedance at this same point, which means this could possibly be a chamber resonance.

Measured sensitivity is right around 86-87dB on average (note the rising response above 4kHz).  The response isn’t flat; it has approximately a 5dB rising response above 4khz, but this response is smooth. There is a 3dB dip (noted above) at approximately 2.4khz trending back up to a 1dB peak at 3.2kHz which correlates to a resonance in the impedance data. Given this is a area is largely comprised of a dip, though, the concern isn’t great.  At 30 degrees off-axis, the response is down approximately 4dB at 10khz.  At 60 degrees off-axis, the response is down approximately 7.5dB at 10khz.  Overall, the on and off-axis response looks quite good up to 10khz where the 60 degree measurement shows a strong dip centered at ~14.4kHz.  This dip doesn’t really concern me because it’s a dip, not a peak, and doesn’t show up in the other axes of measure which indicates this is not a modal issue; rather just a reflection (possibly a reflection off the surround).  While not ideal, I don’t consider it a deal-breaker.

Bottom line:  Really nice polar response.  Good use down to 2khz with a steep crossover.  Though, with the resonance at 2.4khz, I’d think 2.5khz with a 24dB electronic crossover would be a better use for these in a higher output system.  Obviously individual needs/results may vary.

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.

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 D3004/602000 Tweeter: Take Two!


Up for test is the Scan-Speak Illuminator D3004/6020-00 1″ Textile Dome Tweeter, 4 ohm.
This is the second time I have tested this.  The reason for the second test is simply to have a better apples-to-apples comparison now that I have switched to using Dayton’s OmniMic measurement system.  Product specs can be found here.

IMG_2262IMG_2263

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)= 737.50 Hz
  • R(e)= 3.17 Ohms
  • Z(max)= 11.60 Ohms
  • Q(ms)= 6.047
  • Q(es)= 2.272
  • Q(ts)= 1.652
  • L(e)= 0.43 mH

d3004 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.

scan fr 0 15 30 60
To get an idea of the off-axis response vs the on-axis (0 degrees) response, I normalized the above.  What you get is the relative output level of each axis vs the on-axis level.

scan d3004 normalized

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 and 96dB output at 1 meter.


d3004 HD90 d3004 HD96

Impressions/Results

The Fs is measured at approximately 737hz.  To get an idea of what this means on the high-pass crossover, let’s evaluate the HD results.  At 96dB output the THD (blue) is 1.25% at 1khz.  The THD is less than 0.50% down to 1.3khz where it is comprised almost entirely of 2nd order distortion above 1.5khz.   Above 1.5khz there is about 10-20dB separation between 2nd and 3rd order components.

Measured sensitivity is right around 86.5dB.  On-axis, there’s about a 5dB dip centered around 14khz.  At 30 degrees off-axis, the response is down approximately 4.5dB at 10khz.  At 60 degrees off-axis, the response is down approximately 9.5dB at 10khz.  The trough in response from 1.5khz to 5khz is made to appear worse thanks to the high Qts on the low end and the rising response above 3.5khz.  There’s a 7dB swing from 2khz to 8khz thanks to the upward rising response on-axis.

Bottom line: Okay response linearity with great distortion values.  Great polar response with very low distortion above 1.3khz.  This would make a good option for a tweeter in a 2-way system where there is a need to cross low to mate with a larger woofer.  The response linearity may cause you some headaches here but with DSP and the sensitivity of this tweeter, you have some ‘headroom’ to scaled down the rising response to help smooth it out, if needed.

Comparison Against the Gladen 28mm

For what it’s worth, here are some pictures and data comparing this Scan d3004/602000 to the Gladen 28mm tweeter tested here.

IMG_2260 IMG_2264

Here is the on-axis response of both compared directly to each other.  Black is the Scan, Blue is the Gladen 28mm:

scan vs gladen 28

Here’s a comparison of the Scan, Gladen 28mm, and Gladen 20mm (just for the heck of it):

IMG_2265

And the response comparison of all three.  Again, Scan is black, Gladen 28mm is blue and the Gladen 20mm is red.  You can see from this comparison just how linear in response the Gladen 20mm is compared to the larger sibling and the Scan (but the Gladen 20mm cannot cross as low as these other two).

scan vs gladen 28 and 20

Update 03/18/15: Consistency Check

I recently initiated a Group Buy on these tweeters and with the multitude of tweeters ordered, I wanted to see how well the quality control was for each set.  The below image is of an impedance sweep from (7) different units, all brand new in box.  As you can see, the differences are negligible with the largest delta in Qts being 0.006 and Fs being 0.60Hz.  That’s fantastic!

d3004 consistency

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.

Gladen Aerospace 20 Tweeter


Up for test is the Gladen Aerospace 20mm tweeter.  Product specs can be found here.

IMG_2251 IMG_2252

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)= 1073 Hz
  • R(e)= 3.41 Ohms
  • Z(max)= 5.87 Ohms
  • Q(ms)= 1.831
  • Q(es)= 2.536
  • Q(ts)= 1.063
  • L(e)= 0.73 mH

gladen 20 imepdance

 

 

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.

gladen 20mm fr
To get an idea of the off-axis response vs the on-axis (0 degrees) response, I normalized the above.  What you get is the relative output level of each axis vs the on-axis level.

gladen 20 normalized

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 and 96dB output at 1 meter.

gladen 20 aerospace HD90 gladen 20 aerospace HD96

Impressions/Results

Given these are the little brother of the Aerospace 28mm, I can literally copy/paste my thoughts of the build qualtiy:  Let’s start with the build quality… impressive.  These tweeters feel heavy, which one typically equates to build quality.  Though, I’m not a fan of generalizing, that generalization is legitimate in this case.  There is no plastic housing; these are all (some form) of metal.  I’m not necessarily a fan of the large-ish gauge wire.  I do appreciate no terminals (honestly, they usually just cause your cutout diameter to be widdled out even more to accommodate the wire ran to the terminal).  I just think Gladen could have used a tick smaller wire here given most will have to immediately bend the wire in the install to clear whatever pillar or sail panel they install these in.

The Fs is measured at just above 1kHz.  To get an idea of what this means on the high-pass crossover, let’s evaluate the HD results.  At 96dB output the THD (blue) is 2.25% at 1khz.  The THD is less than 0.50% down to 2.5khz where it is comprised almost entirely of 2nd order distortion above 1.5khz.   Above 1.5khz there is about 15dB separation between 2nd and 3rd order components.  Given the fact this is a smaller tweeter physically, the Fs, and the THD results, you can expect to cross this in the region of 2.5khz-4khz, depending on crossover slope.  If you want to use a shallow slope, 3.5-4khz high-pass may be a good safe area with at least a 12dB/octave slope.  If you use a 24dB/octave slope, I’d say 3.0-3.5khz is OK but below 3khz is beginning to push it for a tweeter of this size for high output.

Measured sensitivity is right around 85.5dB.  On-axis, the response is good.  The response exhibits a wide trough centered at about 5khz, resulting in a 2.5dB drop in output.  Otherwise, the response is quite linear.  There’s also about a 1dB dip centered around 11.8khz that fades out the further off-axis you go.  At 30 degrees off-axis, the response is down approximately 3dB at 10khz.  At 60 degrees off-axis, the response is down approximately 6.5dB at 10khz.  Above 12khz the 60 degrees off-axis response drops quickly.  However, 30 degrees is only 3dB below 0 degrees even at 20khz which is quite remarkable.

Bottom line: Very good performance in a compact tweeter.  Great polar response with very low distortion above 2.5khz.  Perfect for a 3-way system with a 3-5″ midrange.

Below are some comparison pictures between this tweeter and it’s bigger brother mentioned earlier:

IMG_2257

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.

JL Audio ZR800-CW 8″ Midbass


Up for test is JL Audio’s ZR800-CW 8″ Midbass.  Specs can be found here.

IMG_2243 IMG_2245 IMG_2250 IMG_2248 IMG_2247

 

Small Signal Parameters

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

  • f(s)= 56.52 Hz
  • R(e)= 5.35 Ohms
  • Z(max)= 54.75 Ohms
  • Q(ms)= 11.113
  • Q(es)= 1.205
  • Q(ts)= 1.087
  • V(as)= 14.310 liters (0.505 cubic feet)
  • L(e)= 0.90 mH
  • n(0)= 0.20 %
  • SPL= 85.21 1W/1m
  • M(ms)= 31.46 grams
  • C(ms)= 0.25 mm/N
  • BL= 7.05

zr800 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.

zr800 fr 0 15 30 60

 

Harmonic Distortion

The following HD graphs are done in the nearfield, emulating the following SPL levels at 1 meter: 90dB, 96dB, and 102dB in order.

zr800 hd 90 zr800 hd 96 zr800 hd 102

 

 

Thoughts

Frequency Response:  Average sensitivity in it’s primary range is approximately 86dB @ 2.83v/1m.  On the low end, the Qts indicates a high value of 1.087 and a Vas of approximately 0.50 cubic feet, which means this driver is likely built for an infinite baffle type install.  According to JL’s literature, that’s indeed the case: “The ZR800-CW is a supremely powerful, dedicated mid-bass driver designed for infinite-baffle or door-mounted custom installations.”  This driver exhibits fairly linear response up until about 500hz where some issues occur.  Looking at the impedance graph you can see a resonance show up in the 600-700hz region.  This shows up in the FR with the strong dip just around 700hz.  From 700-1200hz there’s odd behavior, and above 1200hz the response gets better.

Harmonic Distortion:  I’ve provided HD measurements at (3) different SPL levels: 90, 96, and 102dB.  The reason I do this is to see the general trend of how distortion increases with output.  But since this is a midbass and likely will be pushed hard, I’ll evaluate the 102dB level distortion.  The 3% THD mark is hit at just under 40hz.  From 60-300hz, where these are most likely to be used, the distortion level is approximately 0.60%.  At 500hz the THD reaches 1% and rides that range until it begins to fall at ~1200hz.

Bottom line: As a dedicated midbass in a 3-way type system (or a 2-way using a ‘wideband’ driver) this is an excellent choice.  From the data, it is seen you can reach pretty hefty levels with very little distortion (less than 1% THD) crossing this driver between 50/60hz to about 300/400hz.  This coincides with the FR data as well.  I wouldn’t recommend crossing this higher than 500hz, though because the response gets pretty rough above this point and it would be hard to implement a crossover here.  Regarding the low end output, keep in mind cabin gain comes in to play in most cars at about the 60-70hz region and increases the SPL below this point by ~12dB/octave.  Which means some people may be able to run these without a dedicated subwoofer and be plenty happy … obviously this is very much user dependent, but I will say I’ve done it a few times myself and have had good success using a 50hz/LR2 crossover but I miss my subs too much to not use them.  😉

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.