Dahlquist DQ-10 Supertweeter Sound

stevie b.

New Member
Question - How are the DQ-10 supertweeters supposed to sound? I don't hear very much sound output from either of them and I don't know if this is correct or not. I'd expect more output from them but I'm mostly familiar with three way systems, not 5 way systems such as these.

Background - This weekend I brought home a pair of DQ-10 speakers after auditioning them at the sellers home with my own source material (CD). In the sellers room they sounded nice but once set up at home they immediately sounded a bit dull. After removing the grill frame and rear cage I was able to selectively listen to each driver. There was no output from either tweeter and little output from either supertweeter. All 4 of these drivers worked when tested and the tweeter problem was fixed by replacing both (blown) fuses with appropriate 0.75 Amp fuses.

The speakers sound nice, though I wonder if this can be improved upon. The p/o had the woofers recently refoamed by Regnar. The crossovers have not been updated so I'm contemplating replacing some or all of the capacitors and interested in DIY suggestions.

Thanks,

Steve
 
Steve, what you can or cannot hear from the super tweeters can be related to your hearing acuity or the program content. You could use a multimeter to check the resistance of the piezo super tweeters to see if they're actually working.

If you have a pair of the early model DQ-10's with electrolytic capacitors in the crossovers then by all means they should be replaced with film types. Sand cast resistors would probably be good candidates for replacement as well. Mills or Lynx are good choices. As far as capacitors, opinions on which are best are like armpits. Everyone has some. Really depends on how much you're willing to spend. Personal experience, I would avoid Solen or Bennic. At the reasonable end of the spectrum would be Audyn Q-4 or Clarity Caps. Leave the coils alone as their resistance is part of the crossover design. Just swapping them out for some high flautin' brand may not be the best solution.

Finally, its a good idea to mirror image the mid-range/tweeter sections so one speaker is a mirror image of the other. This will improve imaging.
 

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Thanks for that Homebrew. I'll check the supertweeter resistance and report back on that. My DQ-10 pair are already mirror imaged, and labelled Left / Right. 5 of the caps are yellow and labelled Dahlquist. There's one blue 80 uF cap and two small silver caps. The silver caps appear in circuit to the supertweeters.
 
Question - How are the DQ-10 supertweeters supposed to sound? I don't hear very much sound output from either of them and I don't know if this is correct or not. I'd expect more output from them but I'm mostly familiar with three way systems, not 5 way systems such as these.
Indeed, the crossover point to the piezo is so high as to be almost unnecessary.

I used to sell them back in college days and some folks disconnected them because the Motorola driver could be harsh at times when they did speak in the top octave.
 
Following up on my earlier messages, here's a picture of the Left speaker crossover. I also came across prior threads, notably one titled "Dahlquist super tweeter issues" and it looks like this has been covered before, which frankly shouldn't surprise me.

So, assuming I convince myself that the piezo's are working, I'll just take care of updating the crossover caps. It looks like the basic thing to replace is the 80 uF cap.

Steve
 

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Steve the yellow caps are mylar film. Earliest of the film caps and the least expensive. The blue cap is an electrolytic and that definitely should be replaced. I believe it's an 80mFd. A film cap of the same value would be pretty large and probably wouldn't fit. Since it's a shunt capacitor it doesn't impact the overall sound like a series cap does, so replacing it with a new electrolytic would be the most reasonable solution.

This should work fine: https://www.parts-express.com/80uf-100v-electrolytic-non-polarized-crossover-capacitor--027-358
 
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even though I can feel sound from those online hearing test places to about 16k, I don't 'hear' anything from the piezos on my DQ-10s. But when Steve had his spectrum analyzer set up here, there was definitely something in that range on the screen. very low volume compared to everything else. I'm going with they work and add to the overall sound of my speakers to a degree that makes em sound right. Not that disconnecting them would make my speakers not sound right.
 
I'm no expert on DQ-10's but how old are those mylars and do people replace them? I've been known to replace old film caps too just to get fresh ones in there. It could make a difference.
 
If you are going to go through replacing the caps use Axeon 75 uf polypropylene and Solen caps. I think you can get them from Amazon from partsexpress and you should save heavy charges from Partsexpress. The 75 uf is not that big and if you worry about dropping 5 uf get a 5 to parallel with it. The original caps were 20% tolerance. The bass attack and definition is much better with PP cap than the electrolitic. It is worth the trouble and expense, of about $150.
 
I went with the Dayton 80uF caps. I soldered them in today and I think they actually did make a difference. I listened after I did the right speaker and thought the bass was a bit tighter than the left speaker. Then I went ahead and did the left speaker. Afterwards, I checked the old original blue caps and they measured 115uF and 118uF respectively. Is that far enough out of spec to hear a difference or is it just my imagination?
 
No it is not your imagination, and although people here say they don't change, mine smooted out even more, after a day or so of use. The 80 uf definatly gave me a better defined, and faster bass, and it wasn't in my head. If you have children of sanchez, go to disk 2 band 2, and you can now count the hairs on the bow, in fine definition, that you couldn't before re-cap.
 
Supertweeter follow up. I came across a free android app called "toneGen". Using the app presets, I could hear the 10k tone, but not the 12.5 tone on the Dahlquists nor on anything else I tried. So this clearly shows why I can't hear the supertweeter, which has been noted to only put out above 12k, and obviously my hearing isn't what it used to be. That said, the app is a cheap and easy way to listen to specific frequencies. I can't speak to accuracy though but I thought I'd pass it on.
 
A question regarding something said in a previous reply; Can the higher frequencies be "felt" or noticed even with high frequency hearing loss. I ask this in relation to low bass notes being picked up by the our bones and organs independent of the cochlea. So that would make sense as to what "feels right."
 
I had this issue
I could not isolate the piezo. I tried a tube in front of
I tried a stethoscope
The other drivers bled too much even putting deadening materials in front of them
I always felt i could feel them producing sound. I believe the piezo is situated where it is to round out the higher frequencies
If it werent there thered be a hole between midbass and the glaring dome side
The piezo brings some of that reach over to the midbass avoiding an inbalance in the sound

I took out the fuse to tweeter
Disconnect the midrange.
You will hear the piezo if you can hear above 12k

After that
When all connected back together
Youll be able to identify the piezo sound

Some say its not the piezo at all thats harsh but the 3/4 tweeter instead

So i placed thick felt of at least 1/2" on the baffle boards and the shelf that exists under them of the bass bin

Then i smothered ductseal on the backs of those baffles and drivers
This stuff on the piezo plastic deadens them and certainly makes the baffles less resonating
and also stiffens up the tweeter and midrange assembly when stuffed in its front gap

I put damar varnish on the piezo diaphragm which they say tames unwanted sound quality
Very easy procedure

I recapped the mylars
I believe this put the midrange forward slightly and takes it out from the tweeters shadow just a bit
 
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IMG_20161021_174059_828.jpg IMG_20161021_185311_041.jpg IMG_20161023_000313_251.jpg

The felt ive changed on tweeter side to f11 from ebay but kept a stepped progression from 1/8 right up to dome to 1/2+ by the edge of baffle
Had to thin down the foam around the woofer as it telegraphed through the screen/grill once i cut out areas in front of the drivers
 
The designers themselves heard of fans modding with felt and supposedly tried it themselves coming to the conclusion it wasnt needed

Did they use enough felt?
Right type?
Who knows
But it probably doesnt hurt
Some say it merely acts as a filter suppressing high end

But if the tweeter is overly bright
Maybe thats a good thing

You can always just remove it
 
This thread is from 2017, but I have tested the Dahlquist's Dq-10 cones a lot this past week and I wanted to share this in case anybody is on the same boat in the future. If a Moderator finds that this information is not relevant, feel free to delete my message:

To figure out if the supertweeter works or is blown I isolated it:

1-I disconnected the speakers and connected speaker wire straight to the super tweeter, and then on the other end of the wire I connected the ends to a 9v battery quickly to see if I can hear a click. As soon as I heard the click I stopped.

2-I connected a small and weak amplifier (12 v) straight to the super tweeter and played very very soft music just to see if I could hear it.

In both cases, the supertweeter produced sound. Then I tested the super tweeter with everything connected and these were my conclusions:

When music is played and frequencies go above 12.000 hz, the supertweeter is hard to hear not because it is activated with high frequencies, but because the sound it produces is very soft (as Blue Shadow said). The small dome tweeter, which is right next to it, reaches above 12.000 hz without any problems too and is way louder than the super tweeter, so it is quite difficult or almost impossible to hear the supertweeter because the small dome tweeter "outshadows it". The sound the super tweeter produces is so soft that, despite knowing that the supertweeters work (at least, when isolated), I wonder how much it works and if it affects much the sound when it is surrounded by three other cones.

Above, somebody said Dayton 80uF caps make the supertweeter sound louder than before, so this might be something to consider.
 
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