Alright everyone, here's the story. Like most of us 5th gen owners with Bose, the high end of the system is extremely frustrating to listen to. Very little detail, very laid back, not very responsive (changing the treble in HU has little to no impact at all!) The only good part of the OEM tweeter is that it does fairly well in terms of off-axis response.

I read all the reviews of the Polk tweeter and then went to listen to it at Circuit City. I was not impressed. It was not very detailed and many people have reported that it is prone to distortion at high volume levels with the OEM Bose amp. By the way, it is possible that this distortion is being caused by the iron core coils in the x-over becoming "saturated" and not the result of a defect in the design of the tweeter itself. Also it would be interesting to test that Polk tweeter for frequency response and resonant frequency/impedance curves. Regardless, I wanted somthing better.

I decided to buy the Morel MDT-12 soft dome tweeter. It is about .5 inches deep has really good specs such as an Fs of 1k and very high transient power handling ability and is very linear on axis with good 30 degrees off axis response to well over 10k. I purchased the driver from www.madisound.com . Please note that this is the true "Morel" brand which is designed and manufactured in Israel and not the "copy-cat" US company called Morel USA out of Boston.

I mounted the tweeter in the OEM bracket. To fit the tweeter in the bracket, I had to clip away the upper and lower metal tabs from the bracket (where the original tweeter screwed in), and I also had to trim the two little brackets on side with metal sheers. With a little work bending the frame of the bracket, I was able to get the tweeter in the space. I secured the tweeter to the bracket using zip ties and .5" thick weatherstripping to act as a spacer (note that on one end of the bracket I had to use two strips of weatherstripping not one). I used a 6db/octave x-over that I hand made out of two Axon high performance polyproplylene capacitors, values of 3.3uF and 1.0uF wired in parallel (total capacitance =4.3uF for an x-over point of approximately 4600hz).

The results are phenomenal. The tweeter is very responsive, much more so than the OEM tweeter. It blends nicely with the OEM Bose woofer although it clearly outshines in the woofer in over all sound quality and detail. The tweeter has a very natural and realistic sound. I think any replacement tweeter would be better than the OEM tweeter, but this is a very good tweeter for the money, only $25 each. IMHO they outperform by a significant margin the Polk tweeters many people have been using for upgrades. Although inexpensive, the quality of these drivers is obvious when carefully looked at and even more obvious when listened to. These tweeters would do even better with a two way cross over, optimized for the Bose woofer and this tweeter with a slope of at least 12db/octave and a lower x-over point of approximately 2500-3000 hz. I am currently running these without any custom cross over on the woofer (woofer runs full range with natural high frequency roll-off).

I have pictures of the tweeter, the install and the setup available if interested, please check out this link:

http://www.cardomain.com/memberpage/460442/3

Also, I have some speaker design/measurement software which I used to investigate why the OEM tweeter is so bad. It turns out that the OEM design has a 2.2uF capacitor on it. For a 4 ohm driver, this sets the high pass x-over point at approximately 18000hz. In effect, the OEM tweeter starts dropping in output by 6 decibels for every octave below 18000hz. In other words, a drop of 6 decibals by 9000hz, then 12 decibals by 45000hz and so on. Impedance teting (no pic on site yet) shows that the OEM tweeter has an Fs of about 2000hz at which point it naturally rolls off very steeply. With the capacitor, the roll-off rate is further increased by about 18db/octave.

I took measurements of the OEM tweeter with and without the the capacitor in-line and the roll-off I described is very obvious when looking at the frequency response plots. These plots are available on my cardomain page and there are two plots in one .jpg file. The plot on the left is with the OEM capacitor on the plot on the right is without it. These graphs are not properly calibrated so, for example, 80db could actually be 90db. On the other hand, relative changes in frequency from one point to another point on the graph will be very accurate. This means that a visual 5db change in output from 15k to 10k is a meaningful change in the response curve. Just don't use the curve to determine the "efficiency" of the tweeter. Also, the tweeter itself has a natural dip in its mid band of about -4 to -6 db over a wide frequency band (about 3k to 15k) with a big bump up at both the top and bottom of the frequency response curve. In conclusion the OEM tweeter is really a poor excuse for a tweeter since it is not very linear on axis. There might be an opportunity to upgrade the OEM capacitor with a high performance polypropylene capacitor of about 4uF to improve the OEM tweeter performance. I did not bother to try this. In contrast, the new Morel tweeter has a very flat output through its frequency range of 1k to 20k. Frequency response graphs of the Morel tweeter are available on the Madisound web site for those interested.

 

very in depth, great procedure. I love getting all this onfo on the BOSE you never hear about.

oh and I love the mounting job, those are the tyupes of things I come up with.

Morel is a GREAT choice!

 

I had my tweeters swapped out also back in Janurary, Don did it for for me I got Memphis Tweeters, they sound great especially at above 20 with the treble all the way up, you can really tell the sounds is coming from the pillars.

 

I thought the Bose speakers had a 3ohm impedence and, with the amplifiers tuned for that impedence level, this prevented the successful installation of aftermarket speakers anywhere in the system. Correct me if I'm wrong, please. BTW, are you saying a simple $12 inline crossover/capacitor from, say, Crutchfield could possibly improve the performance of the stock tweeter?

 

Excellent questions.

The short answers:

2K2 Maxima
Bose woofer = 2 ohms
Bose tweeter = 4 ohms
No problem using higher impedance drivers, but sound output could drop especially with the woofers.
Yes, a better cross-over with a lower cross over point could make the OEM tweeter sound louder through its mid-band. What cross-over are you talking about from Crutchfield?

The long answers:

I measured the impedance of the Bose woofer and tweeter from my car (2K2 Max). The OEM tweeter is 4 ohm and the woofer is exactly 2 ohm except at the resonant frequency where it spikes (as expected). By the way, the woofer Fs is almost exactly at 100hz (not good)! Because I took my frequency resonse measurements nearfield (right in front of the driver), I do not have an accurate read on the efficiency of the tweeter or woofer since this measurement needs to be taken at 1 meter with 1 watt of power into the driver. There is no question that the tweeter is severely attenuated by the OEM 2.2uF capacitor on it (this can be seen in the response curves I posted). By using a larger value capacitor, and moving the cross-over point lower, the tweeter will output more sound at higher frequencies. So yes, I believe that a lower cross over point could/would help the OEM tweeter sound better. I'm guessing that the cross-over point was set high for one of three reasons: decrease risk of distortion and tweeter burn out by having too much low frequency output, help the tweeter to mesh better with the woofer (although this is questionable), and help to quell the tweeter's low frequency hump.

Since we know the Fs of the OEM tweeter is 2000hz, an interesting test could be to try a larger value capacitor (which would drop the cross-over point). For example, I just ran some numbers and calculated that a single 5.0uF capacitor would give two octaves of roll-off starting at 8k (instead of the three octaves at 18000hz with OEM cap) before reaching the Fs at 2000hz. This might be a good place to start and see if there is an improvement. Such a capacitor could be purchased from any number of on-line vendors for only a few dollars. I would only recommend using a polypropylene capacitor for this purpose (OEM uses an electrolytic which is an aweful choice by the way). A good cheap brand to buy is Solen or Axon. Check at www.madisound.com. In general, you want at least 2 octaves of attenuation and more is better, higher order cross-overs are more complicated, but they also provided faster attenuation rates and can therefore be used at frequencies closer to the extremes of a driver's frequency response limits.

If you wanted to take it a step further, you could use a 12db/octave cross-over. Just remember that you will probably need to flip the polarity of the lines going to the tweeter to correct for the phase offset. If you wanted to do that, you could use an inline capacitor of 5.0uF and an air choke coil (do not use iron core) of .3183mH after the cap but before the tweeter positioned between the pos and neg lines. This would set the x-over point at around 4000hz and get you down the same -12db by 2000hz as the single 6db/octave cap set at 8000hz.

If you really wanted to get to it, you could also add a low pass filter on the woofer circuit in conjunction with the 12db/octave high pass on the tweeter. If I don't replace my woofers soon, then I will probably do this myself. For the woofer you could use an in-line air core coil of .1592mH and then a capacitor of 10uF between power and ground just before the woofer. This would introduce a high frequency roll-off of the woofer at 12db/octave starting at around 4000hz. This setup would definitely improve the upper midrange a bit in terms of overall output levels and clarity.

You might also consider implementing notch filters to compensate for the two bumps in output in the tweeter.

These 12db/octave cross-overs are designed around the "All Pass" formulas, but you could also try other 12db/octave designs such as Butterworth, etc.

After looking at the curves of the tweeter and realizing how it was performing, I pretty much decided it wasn't worth the effort to work on it very much. I wanted a better tweeter and the Morel is definitely FAR better.

I did take a bit of a chance using the 8ohm impedance tweeter on this circuit, but tweeters draw very little power from the amp to begin with so this really is not much of a concern. In the case of a potential woofer upgrade, this could easily be a bigger issue. Also, any amplifier designed to drive low impedance speaker will not have any problem driving higher impedance speakers. If anything, a higher impedance is easier on an amplifier than a low impedance. The main issue is a decrease in response of the driver. However, I highly doubt that the Bose drivers are very efficient. Typically an increase in the impedance of a driver from 2 ohms to 4 ohms or 4 ohms to 8 ohms will provide a decrease of -3db output when using the same amplifier. However, if the 2 ohm driver is only 87db responsive and a replacement 4 ohm drivers is 90 db responsive, then your total volume should be almost the same!

 

Great post man! I have a quick question or two: Does the Bose amp feed the tweet & woofer separately? Or does it have one feed going into a crossover?

In other words, if I connect an aftermarket 3-Ohm component system, can I still use my own crossover and feed it with the Bose full-range signal?

Thanks,
G

 

Just one line goes from the OEM Bose amp to each pair of front drivers. A set of 3 ohm components with your own cross over should work fine so long as the components are relatively high efficiency. The only issue I can think of is that the Bose amp may have some digital shaping circuitry to help compensate for their crappy speakers. This is only a guess on my part, but I've taken apart the amp, and the components inside seem to suggest this is the case. The signal shaping may influence the overall quality of your sound output . . . I still think you would get much better overall sound than with the original speakers. In the end, you might decide you want to upgrade the amp as well . . . I want to emphasize here that I don't have any facts regarding this signal shaping . . . If you do upgrade everything, let me know how it works out for you. I've personally been considering the Peerless CSX car 5.25" and 6.5" autosound woofers . . .

 

ABS, Great writeup!! Not many people have heard of Morel, but they are very respected. I'm a little confused, though. morelusa.com is based out of Boston as you suggest, but there is a message at the top of the website that states that these speakers are not imitations. Additionally, the madisound.com website seems to have the same model numbers and prices as morelusa. I always thought that the morelusa site is a manufacturer website and the madisound site is a retailer site. I'm just a little confused. Can you help clarify?


Thanks,

Tony

 

Well I think I just answered my own question, because when you click on a link from the madisound website that takes you to the morel website, it specifically warns you about the Boston-based company (morelusa). The actual Morel website (if anyone cares) is www.morel.co.il Unless, of course, I am mistaken.

Tony

 

Tony:

You are correct. www.morel.co.il is the Israeli web site and that is the "real" Morel. I don't know the full history, but apparently the US subsidiary has broken away from the Israeli parent company.

 

Thanks again ABS... now it's time to order some components.

G

 

I just siliconed mine in there, but this would have been way better.

 

I emailed madisound about ordering two MDT-12 tweets. I have been searching on the net about locating the capacitors that you recommended and I want to be sure to order the right thing.

Any recommendations?

 

Sure, I used Axon 250V polypropylene capacitors (it looks like the name is spelled AEON but it is not) because I had them left over from another project, if you want to use them, they can be purchased from Zalytron: www.zalytron.com. Or, just as good, you could order the Solen Chateauroux Metallized Polypropylene capacitors from Madisound. If you want to use the same values I used (4.3 uF), then you should buy a pair of 3.3uF and a pair of 1.0uF caps and wire one of each in parallel on the positive line going to each tweeter . . .

As an aside, since I finished the install and I've been listening to the system more, I've noticed that there is also a lot of woofer output in the 1000-5000hz range. This creates a very "mid forward" sound. I think that in the original Bose setup, the woofer helped to compensate for a lot of the missing low end in the tweeter. If you want to blend your woofer in with the new tweeter a little better than just using the crossover on the tweeter, you could also wire in a single choke coil on the positive line going to the woofer. I've been considering doing this myself. You won't need to go too crazy with this component, just make sure it is an air core. The Solen "Perfect Lay" line are quite nice and not too expensive even one of the Madisound brand coils would do fine. You should use a value of about .069mH. This value is not directly available, but I am nearly certain that Madisound will unwind and measure an inductor's value to get it down to this measurement for a small charge. Similarly, I noticed that Zalytron has a number of options to choose from where the original coil spec is for .10mH. For a .10mH coil, you would need to unwind approximately 33% of the coil to get to the correct value of .069mH. I think Zalytron could help you with that too for a small charge.

Let me know how this works out for you. I must say that even without a choke coil on the woofer, I am still extremely content with the performance of the Morel tweeter!

 

It doesn't look like zalytron will work because they have a minimum purchase order of $50. My order would be less than $10.

 

$50 min order on Zalytron.

bump

 

Sorry about that! I haven't ordered from Zalytron in some time. I just spoke to Terry at Madisound and I was discussing the air core inductors with him. It appears that Madisound will "unwind" an inductor to a provided spec for a surcharge of about 20%. When it comes to the inductors, air core with a low DCR is usually the most desirable. I think that our OEM Bose amplifier only puts out about 25-30 watts so I think the Madisound "Sidewinder" inductor (16 guage wire) would work out just fine for us. It has the same DCR as the standard line of inductors, but is wound with a thicker wire which provides better power handling capability. The price per unit is $2.20 and an additional 20% brings the cost up to only $2.64 each. Terry indicated that Madisound could turn these inductors around in 1 day after an order was placed . . . Also, unfortunately, the Solen "Perfect Lay" inductors can not easily be unwound since they are not wound around a bobbin - these should no longer be considered an option for our purposes. Seems like your best bet, if you want to use the inductors, would be to get them from Madisound.

One last comment, I have used the Solen capacitors on other projects with very good success. To reduce shipping costs, I can see no reason not to keep everything simple by purchasing all components from Madisound . . .

 

Okay ABS, you're talking over my head. In fact, you were from the first post on. But I'm trying to hang with you. If you tell me exactly what to tell Madisound, I will order it. Otherwise, I'm bound to mess up something. Then please tell me how to install the air core inductor for the speaker in the door and what its supposed to do in Lay Man's terms.

 

I am going to email a parts list to Josh at Madisound. I already have the MDT-12's identified. I know what to order for the Solen Capacitors to be wired in parallel. What I don't know is how to tell them about the air core inductors that need to be unwound. I don't know what the part number is or how to direct them in this matter.

BTW, thanks so much for the help.

 

Okay, I'm sorry - I tend to sometimes get carried away with this stuff. When you call Madisound and you speak to Josh ask him for the .1mH (milliHenry) Sidewinder air core inductors. Request that Madisound decrease the value of each of two inductors from the .1mH specification down to .069-.070mH specification. The Bose woofers have a low impedance and that is part of the reason they do not require a very large value inductor. You will need two of these inductors in total. For the installation, you will cut into the positive feed/wire going to each of your woofers and place a single inductor "in-line". I have not yet installed the inductors on my car, so I do not know the best place to mount them. For the tweeters, you should be able to hide the capacitors in a small cavity, within the plastic A-Pillar cover, just above the tweeters. You'll see what I mean when you pull off the A-Pillar covers.

The function of the inductor is conceptually the same as the function of the capacitors - to decrease signal strength and therefore sound output in a certain frequency range. In the case of the tweeter, the capacitor decreases low frequency output. In the case of the woofer, the inductor decreases high frequency output. The overall idea is to let each driver reproduce the sounds it is best at generating. Small tweeters don't reproduce low frequencies very well. Large woofers don't reproduce high frequencies very well. However, the sound output of each driver (tweeter/woofer) does not really "stop" at a given frequency. Instead the sound output decreases as the frequency drops for a tweeter and decreases for a woofer as frequency rises. This inevitably results in overlap between the sound output of the two drivers - this means that they are BOTH reproducing the same frequencies. This will result in an overall increase in sound output in the frequency range where the overlap is occuring since for that frequency range both drivers are producing output instead of just one driver producing output. The inductor and capacitor combination I recommended to you should help to decrease the output of both the tweeter and the woofer in the frequency range that is overlapping. In turn, this should help to smooth out the midrange and minimize the risk of having too much sound output in that one frequency band.

I hope this helps. Let me know how it turns out!

 

ABS,

I have a capacitor question for you that I've been afraid to ask. A few years back I was running my 3-way Dynaudio set actively, without the using the supplied Dyn passive crossovers. I used a Solen capacitor from partsexpress with whatever recommended value as per Dynaudio (it was slightly thicker than a AA battery, but not as long) for the tweeters. So the tweeters were seeing their own dedicated amp channels from a Phoenix Gold 475ZXti amplifer. The amp pushes 75w/channel nominal, however, the gains were turned way down to acheive balance with the midranges and midwoofers. Anyway, one day I was tuning the system using an IASCA test CD and a Radio Shack SPL meter to flatten my system's frequency response. I would then balance the dips and peaks on my 1/3 order PG EQ232 equalizer. When I got to the tweeter realm and the CD was putting out it's test signals in the upper frequency range, I had to bump up the output in the 12+KHz range to get rid of the dip I had in there. My HU's volume was set so that I was staying in the 90 dB range pretty much throught out the test (not too loud so I thought). Anyway, this little escapade apparently arc welded my tweeters. What I don't understand is that even though the amps had the gains turned down and I was increasing the output to the tweeters via the EQ, I assumed I wasn't putting too much power to them because I was still in that 90 dB range. Plus, I also assumed the capacitor was meant to somehow protect the tweeter from overload. I was obviously wrong.

Any ideas?

Tony

 

Tony, I'm not exactly sure what happened to you, but I am a little confused by some of the things you were doing. For example, why use both active and passive crossovers at the same time? In other words, you stated that you were running your Dyn drivers "actively" which I am assuming means with an active electronic crossover. In that case, there should be no need for a capacitor on the input of the tweeter . . . It is possible that you had the cross over point on the electronic/active cross over set at too low a frequency and as a result you were sending too much low frequency signal into the tweeters without realizing it and ended up burning up the voice coil. I am also wondering what process you were using to bump up the output in the just 12k+ range - did you have some kind of EQ in the system for this type of tweaking as well?

Although Dynaudio drivers are extremely high quality drivers, and they typically can take more abuse than drivers from other manufacturers, the fact still remains that signal distortion in general, and particularly at low frequencies, can literally fry a tweeter's voice coil. One other thing to consider, if your amp had it's DC offset knocked out of kilter for some reason, a lot of DC signal could also burn out the tweeter.

I'm sorry this happened to you since Dynaudio drivers are so expensive and I'm sure it cost you a lot of money to replace that voice coil. . .

In conclusion, best guesses are these:

1. High levels of distortion.
2. Low cross over point.
3. High DC output from amp or electronic cross over - should be zero or nearly zero.

Andy

 

After contacting Dynaudio and telling them I was running the components actively, they specifically told me to use that value capacitor with the tweeter. Of course, I followed their directions. I confirmed this information with the Dynaudio distributor as well.

No...the xover points to each driver were carefully set and the system was flawless. The 8-inch midwoofers saw 70Hz-600Hz, the midranges 600Hz-10KHz, and the tweeters 10KHz and above. I could be a little off on the tweeters, but I specifically used whatever value the passive Dyn oxvers used.

I was using my PG EQ232 30-band equalizer to tweak each band. I was aiming for near flat response throughout the entire spectrum. What I usually do is get it as flat as possible for a baseline, and then tweak by ear for the best sound.
What happened is the reponse above 12KHz started to drop off so I was boosting those bands to even the response. I'll admit that the boost was quite high at 16KHz and 20Khz.

I doubt distortion was a problem. The HU was a Nakamichi CD-700 with the aforementioned PG ZXti amp.

And yes, the tweeters were expensive to replace. $200 for the pair.

As far as DC goes, I know nothing about this. Everything in the system was working 100% and then the tweeters stopped working.

My general guess is that the boost was too much for the tweeters, especially in the 16KHz and 20KHz range. I didn't think that it would be a problem since I was only bringing their levels up to "flat" with the rest of the system. I've done this before with other component speakers and never had a problem. The only thing I can think of was it had something to do with the Dyns running acitvely instead of using the passive Dyn xovers.

Oh well.

Tony

 

ABS,

I placed the order with Josh at Madisound for $66.38. This included the tweeters, caps and air core inductors.

Thanks so much for the help. I'll probably email you with more questions later.

 

Great news! I'm curious to hear your feedback after you get it installed. Of interest, over the weekend, I performed additional, and more advanced, cross over analysis on the Bose woofers. I was able to confirm that the choke coil, although small, will cause a decrease in woofer output above about 1k, gradually dropping from about -1db at 1000hz to about -3-4db at about 4000hz. The high frequency roll-off is not as steep as it could be because we are not using impedance correction (a zobel) in the woofer network, but that's ok. IMHO, the mid-forward sound is still a good thing, it just needed to be toned down a bit, and I think that the inductor we selected should work well. If, after you've gotten everything installed, you find that you want the upper mid-range, like electric guitar, to sound a little more laid back, you could try a slightly larger choke/inductor in the range of about .1mH-.15mH.

If you run into any problems or have any questions, feel free to e-mail me, PM me, or post here.

Andy

 

Ok everyone, just thought I would post a quick update on these Morel tweeters. My original install required a 1st order passive crossover on the tweeter comprised of a 4.3uF capacitor (I originally used two capacitors to get this value). After extensive listening, it became obvious that there was way too much output from the tweeter in the 1-5k frequency range. Just this past weekend I bumped up the cross over frequency on the tweeter by removing the 1.0uF capacitor (making the new value = 3.3uF). I can honestly say that this sounds much better than the original configuration. The tweeter itself sounds much smoother and cleaner (it did tend to "honk" a little with the original setup because of too much output at the low frequencies) and it now integrates much better with the woofer. So far, I do not have any x-over on the woofer (no choke, etc.). It was clear before that the sound quality of this tweeter was FAR better than the OEM bose tweeter, but the difference is even more obvious now.

It is my best guess that the Bose amp has a lot of built in EQ function to increase the output of the OEM tweeter between 2-6k . . . I am fairly certain this was the cause for much of the excessive output in that frequency band with the Morel since the MDT-12 has a very flat output in that range.

 

bumping in case anyone is interested

 

I just read this post on rec.audio.car today and thought of you. One of the senior members posted it today:


January 2004


Dear Valuable Customer,

I am writing this letter on behalf of my company, Morel Acoustics USA, Inc.
It is important that I address what has become a pressing issue. Over the
course of this past year, false accusations have been made against Morel
Acoustics USA by a company named, Morel (IL). They allege that we have been
using their name and imitating their products. On the contrary, we feel
that Morel (IL) is using the name "Morel" illegally in the United States.

It is unfortunate that I find myself writing a letter like this. It is not
my intention to put business-minded customers in the middle of this mess,
but as my name and organization continue to be attacked, and my integrity
questioned, I feel that some kind of formal response is necessary.

I started this company over 26 years ago. I was the first person to
introduce the Morel name to the U.S. and world market at the Chicago CES
show in June, 1978. From the beginning, I had been designing speakers with
Meir Mordechai and, as a result of the potential that he saw developing,
Meir decided to join me as a partner. In 1981, we incorporated Morel
Acoustics USA, Inc. Over the next nine years, our company introduced many
new products that included raw drivers, car speakers, and home speakers. At
the end of 1989, Mr. Mordechai sold all of his shares in the company to me,
Mikhael Shabani. From this point forward, I was the sole owner of Morel
Acoustics USA, including the name and all of its assets. A few months
before this transaction Mr. Mordechai illegally registered the Morel logo
under his own name without my knowledge. I did not find out about this
until long after he had left the company. I had paid him a large sum of
money when I purchased his shares only to discover he had abused his powers.
This was the first in a long series of events that led to the deterioration
of my professional relationship with Meir and his staff.

Mr. Mordechai is currently the owner of Morel (IL) in Israel. As mentioned
above, Morel (IL) and its staff have continued the verbal and written
accusations. I want to assure you that these accusations are completely
unfounded. We are the original Morel company. Our products are genuine and
based on designs by our own staff. Furthermore, all of our home theatre
speakers and most of our car speakers have a totally different look than the
product Morel (IL) is selling.

At the 2004 CES (January 8th-11th) we introduced a number of new products.
The most exciting was the Chorus floor speakers - a very small cube shaped
speaker (just under 1 cubic foot) that uses a single 6.5" UniDrive driver.
The suggested retail price is $795.00 per pair and will be available in late
February/early March. The concept of the design and dispersion pattern of
the sound is very unique. Please contact us for more details.

We also introduced a 6.5" inch and a 10" car subwoofer, a new car tweeter
(Triumph!) and a re-designed MR-55 soft dome midrange.

For raw drivers we introduced a new shielded magnet tweeter (MSM-94) and
upgraded MDT-33se soft dome tweeter. The MSM-94 features hexagonal aluminum
voice coil wire, aluminum former, aluminum face plate, treated silk dome and
99% magnetic shielding. The MDT-33se is an improvement over the MDT-33.
The damping material has been changed and the solution used to treat the
silk dome has been improved. The end result is 0.5dB more efficiency,
smoother sound and better detail. The MDT-33se is already available.

I thank you for supporting us in the past and hope to serve you in the
future.


Best Regards,

Mikhael Shabani
President, Morel Acoustics USA, Inc.



morel acoustics usa, inc.
414 harvard street
brookline, ma 02446 usa
tel ~ 617.277.6663
fax ~ 617.277.2415

 

Tony:

Thanks for the info. That is really interesting. I recently read a similar letter, almost the direct inverse, from someone representing the Israeli Morel! If I find the letter, I'll post it here. This whole thing is somewhat crazy! Doesn't matter too much, my tweets still sound nice!