Attenuating the HF on a 604

**cradeldorf** · November 8th, 2011, 02:19 PM

Is there something I can do to attenuate the HF on my 604's? like wiring something onto my crossovers or something? they seem shouty and I can't seem to get rid of it with the EQ.

**Cal Weldon** · November 8th, 2011, 04:39 PM

Do you have some resistors? Try making an L-Pad. Start with a 4 ohm series and an 8 ohm shunt and see what you think. If you have assorted resistors, you can experiment. There are online calculators to help. If you want to change it around get a variable L-pad and read the instructions as to how to hook it up. I can't tell you how many persons use it as a variable resistor and don't realize that it effects the XO. Heck, Altec was bad for that even.

**cradeldorf** · November 8th, 2011, 08:21 PM

Thanks Cal.

**amandarae** · November 9th, 2011, 02:25 AM

I believe the 604 is a combination of 416-8B and an 806/804 HF drivers, if so, then they are 109 and 98 dB sensitive respectively. So, start with attenuating the HF at about -10 dB on the HF using an L pad or with discrete components (resistors), you can make 5.4 ohms in series and 3.7 ohms in parallel to get ~ -10dB attenuation (using 8 ohm driver, for 16 ohm driver, use 10.9 and 7.4 ohms ).

Abe

**tomt** · November 9th, 2011, 03:33 AM

they usually come with that sort of thing ...

the 604 pre-dates the 416 and the 806/804 by several years.

**cradeldorf** · November 9th, 2011, 04:50 AM

I turned on the lo cut buttons on my eq and the speakers sound pretty nice now. gonna listen to them like that for awhile. Seems like it leveled them out nice and smooth now.

**juniper** · November 9th, 2011, 09:58 AM

Cradeldorf, What type of crossover are you using?

**bowtie427ss** · November 9th, 2011, 10:23 AM

I believe the 604 is a combination of 416-8B and an 806/804 HF drivers, if so, then they are 109 and 98 dB sensitive respectively.

That's actually closer to the recipe for a 605. The 604 uses 515 and 802 motors, basically.

**cradeldorf** · November 10th, 2011, 02:49 AM

Originally Posted by juniper

Cradeldorf, What type of crossover are you using?

GPA N-1600 16A crossovers. Like this
http://www.ebay.com/itm/Altec-Lansin...-/230631710252

**juniper** · November 10th, 2011, 10:12 AM

Originally Posted by cradeldorf

GPA N-1600 16A crossovers. Like this
Altec Lansing GPA N1600-16 Crossover NEW | eBay

I was afraid of this, a few months ago I purchased some GPA X-overs but for 604 8-g's. I haven't installed them yet. I have always heard that Altecs can have a shout or a bite to them up top, but with my 604's and X-overs, I have yet to have this type of problem. I can't wait too hear the new x-overs for comparison. GPA does some amazing things!!! Bill is the best!!!!