A7 Active Crossover Choices

[les winter]

My clone A7's are completed. 416z's, GPA 902's, 511b's. A pair of subwoofers starts working at 60hz.


Active Crossover time. My application is home hifi. Classical music.

I tried a search here, but the site doesn't respond.


Currently I'm using a pair of singled ended amps with frequency division via a minidsp 2x4HD. Plenty loud in my large high ceiling room.

Lots of slopes to choose from. 6, 12, 18, 24, 48. Butterworth and Linkwitz Reilly are both available. Also lots of capability to perform room and driver correction. And variable delay for each driver.


First up, frequency and slope choices. I'm presently using second order Butterworth at 800 Hz. It sounds pretty good. I've also tried LR 24db slopes.

What are others using in the active realm?

Thanks for any input.

[BillWojo]

Hi Les, I haven't had the pleasure of trying a miniDSP unit yet but I think one of the features is that you can make adjustments in real time when your hooked up to a laptop.
I think if I was doing what your doing I would get a calibrated mic and the software to do frequency sweeps and adjust as needed. There is also room EQ software that is supposed to make a big difference.
Even if you get someone else's files that work awesome for them, it might not work well in your room. I'm not sure who on here has played with the miniDSP.

BillWojo

[les winter]

Thank you Bill.
I have the mic and the software.
But before I start correcting, I figured I'd get the A7's working the original way, but with an active crossover, and then do room correction. I think the crossover frequency and slope is primary before trimming the tree. Or that is what I think.
thanks again.
les

[LOUDER]

Les, I've always run my 511's at 800 hz. The voice coil of the woofer is 19.3 inches from the front edge of the cabinet. This might set your horn back a little farther
since your using 902's but, it doesn't matter since you have delay. You'll either cut mids or boost highs. Just nature of the beast. I ran passive for years once I went bi-amp I stayed the same. I listen to loud rock and have never blown a diaphragm at that frequency.

[jocelys1]

Hi Les. I run a 3-way Altec with 515RWB/414-16B and 909-8B. Passive between the 909 /414 and active between the 515. The signal is run through the DSP and adjusted for midband EQ rather than using passive components (keeping passive components minimal and all that)

The 414 runs from 1600 and downwards in a sealed box. The 909 is on a Klangfilm horn (clone). It works very well.

[jocelys1]

Les, I'm curious to understand the SUB below 60hz. I've got a pair of SUBs but find that it detracts from the listening pleasure of the Altec sound and always switch it off for music. I can't put my finger on how /why ?

Could it be the efficiency of the SUBs cannot keep pace with the main system ?

Will a pair of tapped horns, size being the main concern with horn-loaded-sub, perform better ?

[mah]

Consider Compression driver protection capacitor when using active crossover with SS amps.: http://greatplainsaudio.com/wp-conte.../07/TL_205.pdf

[Elitopus1]

+1 on the safety cap mah.

When I biamped my 817a cabs/2360 horns, I used some motor run caps for safety caps. You can get large values for cheap in the motor run caps or NPE caps.

[Phil-G]

Les, I'm curious to understand the SUB below 60hz. I've got a pair of SUBs but find that it detracts from the listening pleasure of the Altec sound and always switch it off for music. I can't put my finger on how /why ?

Could it be the efficiency of the SUBs cannot keep pace with the main system ?

Will a pair of tapped horns, size being the main concern with horn-loaded-sub, perform better ?

I've been using a single sub loaded with a pair of 3154s seems to blend in well.

[les winter]

Les, I'm curious to understand the SUB below 60hz. I've got a pair of SUBs but find that it detracts from the listening pleasure of the Altec sound and always switch it off for music. I can't put my finger on how /why ?

Could it be the efficiency of the SUBs cannot keep pace with the main system ?

Will a pair of tapped horns, size being the main concern with horn-loaded-sub, perform better ?

Hi
I think it depends on the subwoofer design. I use air suspension enclosures with very low Q, in the order of 0.5. Accordingly there is no "hangover". The driver (eminence lab12) meshes with high efficiency mains very well. Higher Q designs maybe not so much.

I have no experience with vented subs so I won't comment on that.