Hi Guy’s, my first post on this forum and hope I'm not breaking any rules, please let me know if I am.
I need your help on a Dahlquist DQ-20 crossover question. I rebuilt my 20’s and put in new tweeters , I replaced the stock Scan-Speak D2008 with a pair of Hiquphon OW II’s, about the only difference in the speakers is that the OW II’s have a 90db nominal sensitivity and a little less high end roll off and the D2008’s have a 88db nominal sensitivity. I recently moved and in my new man room the tweeter is a little too hot and me with no tone controls. My question is what would be the proper way to damp down the OW II’s down either 2db or 3db, (will experiment with both to see which sounds better) I put a 2.7ohm 10watt resistor in series as a test and it made a huge difference of moving in the right direction but with just a 2.7 in series it raised the z ohm total from 8 to 10.7 ohm at the tweeter, as I did this just as a test and liked the results except for the new 10.7 ohm total. It looks like I have 4 options
1. A resistor in series (worst option I think)
2. A high quality L-pad (your thoughts use it to find the right sound then remove and put in series and parallel from l-pad measurements or leave the l-pad in place)
3. Wire in a series and parallel resistors just before the tweeter. (using l-pad calculator to for either 2 or 3db attenuation)
4. Or replace R1 in the schematic from a 4ohm 5watt resistor to ? said value for 2db or3db attenuation (Please help here DQ 20 Schematic is the attachment) would I also need to change the R3 100ohm 3 watt value? To keep the proper ohm load at the tweeter? This seems like the best option as I am not adding any extra components to the cross over but not sure if this changes the designed ohm load at tweeter or if it is okay?
I hope that this all makes sense, the old D2008’s are toast and I love the OW II’s just a little too hot and not ready to invest in sound panels yet (next upgrade to the man room) Thanks in advance for the help. Thanks again, Paul.
I need your help on a Dahlquist DQ-20 crossover question. I rebuilt my 20’s and put in new tweeters , I replaced the stock Scan-Speak D2008 with a pair of Hiquphon OW II’s, about the only difference in the speakers is that the OW II’s have a 90db nominal sensitivity and a little less high end roll off and the D2008’s have a 88db nominal sensitivity. I recently moved and in my new man room the tweeter is a little too hot and me with no tone controls. My question is what would be the proper way to damp down the OW II’s down either 2db or 3db, (will experiment with both to see which sounds better) I put a 2.7ohm 10watt resistor in series as a test and it made a huge difference of moving in the right direction but with just a 2.7 in series it raised the z ohm total from 8 to 10.7 ohm at the tweeter, as I did this just as a test and liked the results except for the new 10.7 ohm total. It looks like I have 4 options
1. A resistor in series (worst option I think)
2. A high quality L-pad (your thoughts use it to find the right sound then remove and put in series and parallel from l-pad measurements or leave the l-pad in place)
3. Wire in a series and parallel resistors just before the tweeter. (using l-pad calculator to for either 2 or 3db attenuation)
4. Or replace R1 in the schematic from a 4ohm 5watt resistor to ? said value for 2db or3db attenuation (Please help here DQ 20 Schematic is the attachment) would I also need to change the R3 100ohm 3 watt value? To keep the proper ohm load at the tweeter? This seems like the best option as I am not adding any extra components to the cross over but not sure if this changes the designed ohm load at tweeter or if it is okay?
I hope that this all makes sense, the old D2008’s are toast and I love the OW II’s just a little too hot and not ready to invest in sound panels yet (next upgrade to the man room) Thanks in advance for the help. Thanks again, Paul.
Attachments
Your best bet could be a simple 2 or 3dB LPAD at the tweeter, this will not affect cross-over points or anything else, although arguably unless the tweeter is identical other than sensitivity some measurements would be in order if possible. (Redesign XO for the current tweeter)
Don't worry about the impedance. A resistor in series (before R1) works fine and does no harm.
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Thanks for the welcome KevinKr, The speakers have almost identical specs and supposedly designed by the same person, I have a Fostex L-pad coming but should have waited for more information, you guy's are great, Thanks a ton. Paul.
Thanks so much Dissi, so putting the resister on the crossover before r1 won't have same effect that I am getting by putting it on the positive connection at the tweeter? and I don't have to change r3? sorry I'm new to this and Thank you so much for the graph I will be ordering some resisters next week as I think this will be the best way to go even though I just ordered an L-pad. Thanks again you guy's are the best!
Well here's one for the books, never thought changing the speaker cables would have such a dramatic effect. I replaced the 20+ year old audioquest blue cables with five of each conductors with a set of Clear Day cables double shotguns and even prior to the break in period, the problem is solved I even removed the 2.7 resistor and all the harsh brightness is gone and there is a much more potent bass too boot, really surprised at the dramatic difference, system now sounds better then I ever dreamed it would. Thanks again for all the help. Still might add the 2.7 prior to R1 on the crossover but I think I need to give the cables some time to settle in and see what happens. Thanks.
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