Dahlquist DQM-9 speaker trouble

[evallded]

Hey guys just a quick question for those in the know. I picked up a pair of Dahlquist today at an estate sale after reading rave reviews about them everywhere.

I got them home and one of the posts needed re-soldered. and aside from that they sound great except for one of the mids sounds a little quieter than the other. Pushing in on them a little one of them moves smooth but needs much more force to depress it, there is no way this is reacting fast enough to operate the way it should. I dont know if maybe this is a sign of it going out or what would cause this.

Thinking about sending them in to Dahlquist for service but I am not sure of the price yet. Any ideas?

 

[Freddymac2]

Dahlquist is gone! Regnar may have parts and repair services. His mods and services can be expensive. It sounds like a partially smoked voice coil.

 

[evallded]

Yes the website was Regnar. I thought Dahlquist was gone as well but upon flipping through the page it seemed to be something official. I had kind of figured it may be a voice coil but I have never had one partially seize up, nor seize and still move smooth. I will wait and hear what they have to say about rebuild prices. Thanks for the reply!

 

[swechsler]

It's a fairly standard cast frame driver, any place that specializes in driver repair should be able to handle it. Check out Millersound to see if they can do it. Or look for a replacement on eBay.

 

[gdmoore28]

What Swechsler said. AK has some speaker repair folks that come highly recommended, and that would probably be the best way to go to ensure that your mid is up to specs. Otherwise, the ebay route could be your ticket. Let us know how you make out.

GeeDeeEmm

For reference: Dahlquist DQM9

 

[evallded]

Well I am not getting anything out of Regnar. I would love it if someone could recommend someone for rebuilding these, or somewhere I could get the parts to do it myself. Thanks again guys. That one mid speaker aside, these are so impressive sounding, I am just blown away!

 

[swechsler]

I already did in my previous response. Millersound.

Also, there are currently a couple of auctions on eBay selling DQ-20 midranges, that look like they could be the same as those from the DQM-9. Prices are on the high side, but at least one of them is accepting offers.

I also note that these midranges are German-made. It's possible that they used an off-the-shelf driver, so if you can figure out who made it, you might be able to find the same midrange for less. There's a possibility that they were made by Magnat, since I think they used Magnat tweeters in these (they did in other speakers in this series, anyway).

Here are a couple of pics in case anyone recognizes them:

ETA: eBay completed auctions tells me that they are Magnat drivers, and some sold at a fairly reasonable price about a month ago. If you can be patient, set up an eBay automated search and maybe one will appear soon.

 

[evallded]

[QUOTE="some sold at a fairly reasonable price about a month ago. If you can be patient, set up an eBay automated search and maybe one will appear soon.[/QUOTE]

1 step ahead of ya on that one. I seen the ones that sold and in my own town too, argg. Timing huh?

I have been doing some looking around but have yet to pull up anything definitive as of yet.

 

[evallded]

Ok, a little update. So I have kept an eye out for anything I could find locally and I ran across a couple pairs just 2 hours from me. He would only sell together but the price was fair and I though that would allow me to fix mine, sell off another pair and part out whats left doing better than breaking even in the end. However......

I got there and 3 of his cabinets had mids that were responding exactly as mine were. So I paid a little less and knowing I could still fix mine for a fraction of what Regnar would charge I went ahead. But again (insert dramatatic however here)........

I got htem home and proceeded to pull out one ofthe "bad" mids. When I got it out I realized it felt fine. It was nice and springy and popping right back out as it should. So as I started to put it back in in an attempt to locate the problem I got it half way screwed down and still good. It was only at fully tightened up that the problem returns. So, what could this be? Bad airflow to the upper portion of the cabinet? It does not appear to be a problem with insulation material pushing in on the cone. And I have no reason to believe it could be the frame torquing it crooked. Any thoughts?

 

[swechsler]

Now that you described it in more detail, the behavior you've experienced is what you'd expect from a sealed enclosure (especially from a typically small enclosure you'd expect with a midrange driver), and the other enclosure (the one that moved in and out freely) may have a problem (i.e. it's not well sealed). It's possible the problem lies with the crossover or the driver. I'd first try putting in one of the new drivers to see if it resolves the issue. If not, try swapping between cabinets, and then if you've narrowed the problem down to the cabinet, first check to make sure the fuses and fuse holders in back aren't corroded and making good contact (clean them with contact cleaner if necessary). After that, it's probably time to recap the crossovers (I would do the crossovers in both speakers).

Also, I'd investigate the cabinet where the midrange moved smoothly. See if there's a leak in the midrange enclosure, or the frame isn't making good contact with the baffle. Since this appears to be a sealed design, you might need to use caulk between the frame and baffle to get a good seal.

ETA: btw, you now have the makings for a fine surround system, if you decide to go that route. I suspect that the speakers you just purchased are fine.

 

[evallded]

Now that you described it in more detail, the behavior you've experienced is what you'd expect from a sealed enclosure (especially from a typically small enclosure you'd expect with a midrange driver), and the other enclosure (the one that moved in and out freely) may have a problem (i.e. it's not well sealed). It's possible the problem lies with the crossover or the driver. I'd first try putting in one of the new drivers to see if it resolves the issue. If not, try swapping between cabinets, and then if you've narrowed the problem down to the cabinet, first check to make sure the fuses and fuse holders in back aren't corroded and making good contact (clean them with contact cleaner if necessary). After that, it's probably time to recap the crossovers (I would do the crossovers in both speakers).

Also, I'd investigate the cabinet where the midrange moved smoothly. See if there's a leak in the midrange enclosure, or the frame isn't making good contact with the baffle. Since this appears to be a sealed design, you might need to use caulk between the frame and baffle to get a good seal.

ETA: btw, you now have the makings for a fine surround system, if you decide to go that route. I suspect that the speakers you just purchased are fine.

Thank you Swechsler you are completely correct. Right after I wrote the last reply I pulled the insulation out from behind the speaker and seen that it was a small sealed tube that the mid sits in so it would be perfectly normal for the reaction of the speaker to be quite slow. And correct again in that it is probably the one I thought was operating properly that has an issue and that the sealed tube may have fallen loose inside the speaker cabinet. What a flip flop from what I was thinking, it really threw me off. I am assuming now any clipping I heard from the speakers was caused by my amps not being powerful enough to power them.