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Old 20th September 2008, 06:43 PM   #1
Ila is offline Ila  Germany
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Default Scan Speak D3004/660000 problems

Scan Speak D3004/660000 problems

For several months I am working on a high performance monitor speaker for a commercial product. At the moment Scan Speak drivers are used throughout. After numerous iterations, I settled at a combination consisting of a 15W/4531G00 + 12M/4631G00 + D3004/660000 in a vented application.

I would like to go ahead and bring this project to an end, but there are major problems with the D3004/660000 tweeter.

One of the two tweeters supplied for our first experiments was faulty. Well, I thought it might be possible that we have damaged it by ourselves Ė but this was not the case. The dealer was nice enough to replace one unit Ė and after that everything was in good working order. No problems there after. Once again we sourced all new drivers because the test speakers were sold. Again one (only one) of the D3004 tweeters comes with the same problem that we encountered before.

The problem with these faulty tweeters is that they resonate mechanically and thus very audibly at input frequencies well above fres = 500Hz. A very small voltage level (less than 50mVrms) with a steady frequency in the range of 1200 Ė 3000 Hz is sufficient to trigger the resonance. Below the trigger voltage (trigger means, the effect does not come gradually, but abrupt) everything is absolutely normal. Above the trigger voltage, the driver impedance rises and the acoustic output is distorted or better say intermodulated.

Interestingly with music signals most of the time you wonít notice this resonance problem, because the signals are varying to quickly and some sort of steady level and frequency is needed. It is quite clear, that the audibility of this resonance effect depends largely on your filter order and the crossover frequency.

Since it is a mechanical problem, you can alter the ďtrigger pointĒ simply by pressing the back cover gently.

Is there anybody out there, who knows about problems with these tweeters? Is it really bad luck, if 2 out of 4 units donít work properly?

Tymphany is not willing to comment on this subject Ė which is a pity because otherwise the D3004/66000 is an excellent driver.

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Old 20th September 2008, 09:09 PM   #2
PB2 is offline PB2  United States
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Are you certain that they do this right out of the box, or is it possible that they're damaged in use due to too gradual of a XO slope or excessive power? What is the crossover that you're using? Rough order, and XO point?

On the other hand, it sounds like a sympathetic vibration problem because you'd not expect pressure on the plate or sides to alter the dome behavior. While, of course you shouldn't have to do this would some damping compound pushed in around the gap between the magnet and front plate solve the problem? Model clay or Mortite for example. Might be worth an experiment.

Pete B.
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Old 21st September 2008, 09:50 AM   #3
Ila is offline Ila  Germany
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Default D3004/660000

Hi PB2,

I am pretty sure, that it is impossible that I have done something damaging to the D30s.

Last time the speaker came right out of the box, and they were

- mounted on a flat surface (no mechanical stress)
- soldered only one time and very cautious too (no overheating possible)
- no CLIO measurements without crossover attached

The crossover was 3rd order and 2000Hz and is now 2nd order and 4000Hz. The characteristic is basically (electrical) Butterworth, so no overshoots etc. Relative to the woofer the tweeter level is 6dB down now and was 9dB down in the older versions.

Since the design is a small monitor speaker and not a PA system, excessive power is not an issue here (moderate listening levels).

I could dissemble the unit and probably see what causes the trouble, but

- I want lose my warranty rights (return the unit to the distributor)
- I canít do that if a couple of speakers are being manufactured

Thatís what is driving me mad: should I drop a nice speaker design because of the reliability problems described or is it bad luck? I really donít know.

At the moment there are no commercial products (why not?) to take advantage from. (Wilson Audio Duetta tweeter is a custom design) As far as I know, there are some DIY concepts (Zaph ZRT or the Master from Profession Concept Audio Denmark).

Thanks for your advice anyway.

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Old 21st September 2008, 10:26 AM   #4
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several companies are using this tweeter, in large quantities by SVS (better known for their subwoofers). SVS speaker with scanspeak 6600

The newer offerings of Rockport also seem to use this tweeter.

Can you comment on the age of the tweeters used? When te first series became available it was soon sold out, because of production issues. It was replaced with a slightly lower sensitivity version. Which was easier to produce (IIRC something to do with tolerances in the coil/magnet assembly)

I own a pair of the first version, but I didn't check with steady state signals. I only used chirp test tones for the measurements.
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Old 21st September 2008, 11:39 AM   #5
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Hi,

I wouldnt recommend that you disassable it. Its almost impossible to assable again. I got a pair where one of the terminals were broken off, and i pulld it apart. It took me more time to assable then to fix the tweeter.

Btw, i would look to far at pca. I know the danish company, and i dont think he has sold a single one yet. They have a very poor reputation here in denmark regarding crossovers.

Do you have raw meassurements of the drivers in the enclosure? I would love to try a crossover suggestion.

Mail me if your interested. henrik at speakerbuilder dot dk. I have clio and lspcad. I have helped danskaudioteknik, genesis and jumonaudio with filterdesigns.
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Old 21st September 2008, 02:52 PM   #6
Ila is offline Ila  Germany
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Hi guys, thanx for your input.

The first box with D3004/660000 was from 2007, the actual ones are from 2008, production week 22 Ė I would call that brand new.

The SVS speaker company definitively uses this tweeter, but SVS is nearly unknown here in Europe. By that, it is hard to say if quality problems may exist. The Rockportís locking very nice indeed, but as the faceplate is partly covered, you canít say what they are actually using; it could even be a Vifa XT25 or an OEM version. Rockport hasnít got a distributor in Germany for years, so it is the same as with SVS.

Another puzzling aspect of the D3004/660000 tweeters is that you can read here and there (see Rockport website too), that these drivers (or derivates) can operate at relatively low frequencies. Yes, it is a 1íí soft dome, the resonance frequency is low and there is sound pressure in the 1000Hz region; but how does this sound? For me and the whole listening crew it sounded awful, if these drivers had to work to hard. Relieved from larger excursions (XO>2.5 kHz) I would say that these drivers live up to their potential.

The prototypes are almost finished, normally I would not change a thing; but if the mystery canít be solved the R2907/700000 would be the replacement. Henrik, any comments on that? (Except for an even higher price tag)

Ivo
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Old 21st September 2008, 03:24 PM   #7
Shaun is offline Shaun  South Africa
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Hi Ivo

I have seen DIYers trying to use high-value tweeters at low crossover points. These are tweeters that have very low distortion when used in typical crossover configurations (say, down to 1800Hz). From their comments I have observed that they like to cross over at around 1400Hz (maybe lower). But it is a hit-and-miss affair, because they report inconsistent behaviour between examples of the same model when used this low. The same tweeters operate flawlessly when crossed over higher. You may be seeing more of the same behaviour, and perhaps this is a general problem (i.e., getting consistent distortion performance from tweeters when crossed low).

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Old 23rd September 2008, 02:14 AM   #8
iseeall is offline iseeall  Singapore
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Hi Ila, I am having the same problem as you.
In fact, its worse.
I have it in 2 of my tweeters.
Btw, I am running it in my car using active crossovers.
The distortions happens mostly on piano notes and its in the frequencies you mentioned.
My dealer is helping me with this and I, myself, am also trying to contact Tymphany for warranty for weeks now but no response.
Its frustrating!
I have posted this on Diyma as well under the D3004 660000 review done by npang.
My tweeters are only 3 months old.
Overall, they are still good speakers except for this problem.
Have you found anyone who can help or have u a solution to resolve this problem?
Its a shame for this to have happened; the D3004 660000, despite the problem, are pretty good tweeters.
Btw, I am from Singapore.
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Old 23rd September 2008, 02:37 AM   #9
PB2 is offline PB2  United States
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Default Re: D3004/660000

Quote:
Originally posted by Ila
Hi PB2,

I am pretty sure, that it is impossible that I have done something damaging to the D30s.

Last time the speaker came right out of the box, and they were

- mounted on a flat surface (no mechanical stress)
- soldered only one time and very cautious too (no overheating possible)
- no CLIO measurements without crossover attached

The crossover was 3rd order and 2000Hz and is now 2nd order and 4000Hz. The characteristic is basically (electrical) Butterworth, so no overshoots etc. Relative to the woofer the tweeter level is 6dB down now and was 9dB down in the older versions.

Since the design is a small monitor speaker and not a PA system, excessive power is not an issue here (moderate listening levels).

I could dissemble the unit and probably see what causes the trouble, but

- I want lose my warranty rights (return the unit to the distributor)
- I canít do that if a couple of speakers are being manufactured

Thatís what is driving me mad: should I drop a nice speaker design because of the reliability problems described or is it bad luck? I really donít know.

At the moment there are no commercial products (why not?) to take advantage from. (Wilson Audio Duetta tweeter is a custom design) As far as I know, there are some DIY concepts (Zaph ZRT or the Master from Profession Concept Audio Denmark).

Thanks for your advice anyway.

Don't know what to say, perhaps it is a design flaw that they need to iron out.

Pete B.
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Old 23rd September 2008, 03:32 AM   #10
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Hey Iseeall bro, just wondering where did you get your 6600 here, car audio dealer?

Actually SVS had sort of a recall for their MTS speakers...no charge fix. Now they have new xovers. Not sure if its related.

http://www.svsound.com/news-news.cfm
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