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Doogster
03-02-2007, 05:43 PM
Hi chaps

I've got 2441s on 350Hz round tractrix horns which I'm using from 700Hz up (I'm using 12db passive line level crossovers).

There is some definite peaking going on. My crappy Rat Shack SPL meter tells me it's in the 4.5kHz to 5.5kHz range, with a pronounced peak at 5kHz. My ears tell me pretty much the same thing.

Is this a normal response for 2441s on tractrix horns? Any suggestions for how to eliminate the peak? Is it something only EQ can resolve? I was thinking of going 3-way by using 2404Hs at around 5kHz. That way I could use a band pass XO for the 2441 (say, rolling off the 2441s at around 4kHz). Or would a notch filter on the 2441s be better, with the 2404Hs coming in much higher (eg. 10kHz)?

Any suggestions gratefully appreciated.

Cheers. Doug

Zilch
03-02-2007, 08:13 PM
Get decent measurement equipment. The Radio Shack microphone is seriously wrong between 4 kHz and 10 kHz. Unless that's corrected in the display algorithm, the meter overstates the response between 6 and 8 kHz by ~6 dB:

http://audioheritage.org/vbulletin/showthread.php?p=127276#post127276

I was able to smooth out LE85s nicely with a parallel trap notch filter:

http://audioheritage.org/vbulletin/showthread.php?p=135642&#post135642

Values for the one shown are 0.1 mH, 4.3 uF and 8 Ohms.

Earl K
03-15-2007, 08:11 AM
Get decent measurement equipment. The Radio Shack microphone is seriously wrong between 4 kHz and 10 kHz. Unless that's corrected in the display algorithm, the meter overstates the response between 6 and 8 kHz by ~6 dB:

- I agree with Zilch. One needs something much better than a Rat Shack meter to acoustically guide your way through the process of building filters .

- We found out about the dangers of being referenced to a Rat Shack meter when dmtp ( ? ) was engaging our interest with his round tractrix horn project.

- TrueAudios' TrueRTA ( set to sine wave ) has impressed me with what I've seen of it. Also, it's very affordable . This is what dmtp bought last Nov. This product isn't windowed (MLS ) / which as the CLIO Club has found, isn't the end of the world .


I was able to smooth out LE85s nicely with a parallel trap notch filter:

Values for the one shown are 0.1 mH, 4.3 uF and 8 Ohms.

- Myself, I prefer the sound of series LCRs strapped across the driver .
- Parallel LCRs vs Series LCRs have 2 different damping signatures ( at least to my ears ).As a result, I don't consider their application & usage as being completely interchangeable . ;)


:)

scott fitlin
03-15-2007, 09:16 AM
Yes, the 2441,s on my 2395 horns do exhibit a peak, but on my RTA its in the 2.5k region.

I use EQ to tame the peak.