I Need Help with My Crossover

[Mike16W]

I am trying to upgrade my crossover. Right now I have a N800-E crossover with a stepped attenuator. I am using a 802-D high freq. driver and a 803-B woofer. I believe the crossover has two 10.5uf caps and two 3.0 mH inductors. What do you recommend? Just replace the individual components and put in a L-Pad? Is there any schematics of the N800-E? Thanks for any suggestions.

[GM]

Originally posted by Mike16W:
I believe the crossover has two 10.5uf caps and two 3.0 mH inductors.

<font size="2" face="Verdana, Helvetica, sans-serif">Yes it does IIRC. Personally, I'd step up an order of magnitude to a high SQ digital unit with adjustable low/high pass point, levels and time delay, so you can dial it in to suit in-room.

For passive, so many folks claim that the M-19's ~1200 Hz XO is the best sounding of the 811's various XOs, so seems a good choice, though ideally you'll have to relocate the 811's front/back location to get the most out of it: http://home.earthlink.net/~jmarkwart...1201-8aRev.pdf

I forget the horn setback, but it can be figured from the plans and don't forget to account for the offset difference between a front and rear mounted woofer: http://home.earthlink.net/~jmarkwart/id14.html

GM

[Mike16W]

Thanks GM.
I tried an active crossover and it destroyed any soul within the music. I have had experience anytime I use one.
The crossover looks interesting. I'll do some research on it. Do you know what L-Pads are used in the crossover?

[westend9]

811 is setback 2" from the woofer. I've been using the Behringer CX3400, 811-802g, 416b. There is a CD compensation circuit feature on this crossover. Adds a few db as frequency rises.
I am impressed with the active crossover. It certainly isn't adding anything or taking away. The one difference I do note is that the phase is very coherent. Instead of hearing the low and highs as separate entities and not complimentary, the lows and highs seem to totaly fit and compliment each other. Maybe it's just me.

[Mike16W]

Thanks, Is the 811 set back 2" from the face of the woofer or from the magnet area and should I measure from the front part of the 811.
Do you find that the electronic crossover causes the music to loose it's warmth that is there with a passive crossover? I am running 2A3 tube amps and would like to keep the emotional aspect of the tubes.

[GM]

Originally posted by Mike16W:
Thanks GM.

I tried an active crossover and it destroyed any soul within the music.

Do you know what L-Pads are used in the crossover?

<font size="2" face="Verdana, Helvetica, sans-serif">You're welcome!

Strange how we all hear the same, yet not so much. For me the 'soul' is always there (if there's any to begin with, much has none IMO), but going active lifted a heavy veil covering the music, though admittedly the electronics were not your garden variety prosound or 'blowout sale of the week' fare, but then look at the cost of a premium passive XO.

No, I'm not familiar with it in detail, but there's others here who are.

GM

[GM]

Originally posted by westend9:
811 is setback 2" from the woofer.

Instead of hearing the low and highs as separate entities and not complimentary, the lows and highs seem to totaly fit and compliment each other. Maybe it's just me.

<font size="2" face="Verdana, Helvetica, sans-serif">Hmm, got a chance to check it and this assumes a front of baffle mounted woofer whereas the older drivers are rear mounted, so the offset from the rear of the 811's mounting flange is 2" + baffle thickness + mounted driver flange/gasket thickness.

No, not just you........

GM

[Tom Brennan]

GM---Do you mean the 19 crossover does the time-aling thing and adjusts for path difference between woofer and tweeter?

If true then using 902s instead of 802s would throw things off as the diaphragm of the 902 is closer to the horn throat than that of the 802.

Just wondering because the other day, while totally bored, I switched the 802-Gs in my 19s for 902s.

Another thought; the horn built into the 902 body must have a higher flare rate than the 802 right? It travels less distance from the diaphragm to the 1" opening than with the 802 so it must have a higher flare rate. I wonder if that makes a better transition to the horn then.

[GM]

No, the horn's physical setback does this so that it doesn't have to be done electrically.

That said, the M19's XO uses pots to adjust levels and EQ the horn with the former affecting the phase response through the XO BW, so the setback isn't correct for a simple XO such as a 1200 Hz/2nd order textbook Butterworth filter and if an ETC plot was done we'd probably find that the setback/XO is designed to 'steer' the horn/woofer's summed response in a slight upward angle due to the horn being somewhat below the average seated ear height. Rane's tech note #107 is the best ~layman's explanation of any I've read: http://www.fullcompass.com/common/fi...Crossovers.pdf

WRT the acoustic center of a compression driver, it will be pretty much at the front face of the phase plug, so you're right that switching out different mating 'flange-to-phase plug' depth drivers will affect the phase/'steering' angle.

Flare rate (AKA flare frequency) describes the wall angle expansion rate while its axial length defines its 1/4 WL fundamental.

Frankly, I can't remember much about the 900 series internal design details since I had little use for it due to it not loading well on 500 Hz XO'd horns, but obviously it would have to be shorter and if its throat is the same size as the 800 series, then yes, it has a 'faster' flare rate (frequency) which combined with a shorter total horn length would explain its poor LF loading compared to the 800 series.

WRT driver/horn transitions, the best is when the two match, so a shorter/'faster' flare transition to a much 'slower' flare causes reflections back to the throat (part of Dr. G's HOMs) and no doubt in my mind why the 900 series's 'sawtooth' response on a 511 is far worse than an 800 series's, though due to the way we perceive sound I don't consider either driver series being a clear winner when BW limited, though I prefer the 802-8G overall as it gives the most balanced trade-off between LF horn loading and HF extension. For higher than 800 Hz XO points, the 900 series seemed to me a better choice back when I had HF hearing, but the reality is that they all need super tweeters to get a ~flat power response and that last bit of HF detail that makes up the leading edge of ultra fast transients generated down in the 250-500 Hz BW.

GM