I ordered the 950/770 combo today. Hopefully I'll have lots of time to play with them this weekend.

Maybe I missed this in the PDF of the manual, but I couldn't find a specification for the crossover slope when employing the 80 HZ analog crossover and analog inputs.

Also, is there a problem in keeping the subwoofer level in balance if you use a different crossover point for digital vs. analog input?

One last general question. Is is appropriate to use the speaker manufacturer's -3 dB bass point in deciding where to set the digital crossover point. I have read that about 2X the -3 dB frequency is usually appropriate. Applying that to my main speakers (Polk LSi 9's) would put the crossover frequency at ~100 HZ, a little higher than I'd ordinarily chose.

If the kind of (generally) thoughtful and helpful discussion I've seen on this board continues, I think the Outlaw's business model is going to work well. A lot more knowlege here than in most HiFi stores.

MIKE

That's just a rule of thumb. YMMV. Experiment with different crossover points after you get your unit. However you'll probably want to get used to its sound, first, else you might make one decision when you first get it, only to make another decision after you've grown accustomed to it. Also, as you get used to your system, you may find yourself moving your speakers around a little and doing other little room tweaks to get your room to sound better.

The 950's subwoofer level is a global setting. You can't set it to one specific level for analog, and set it to another specific level for digital.

I also don't know what the crossover slope is or if it's a linear slope.

Enjoy your new system when it arrives!

Will

[This message has been edited by Will (edited October 30, 2002).]

The double/half frequency recommendation for xover use is generally applied to a xover with -24dB slope. Specifically in the case of many prepros, the low-pass gets a -24dB slope, but the high-pass only gets -12dB slope because they expect your speakers to roll-off with a -12dB slope thus summing to -24dB slope for the high-pass.

Typically the only speakers that meet this -12dB roll-off spec are THX speakers @80Hz.

Sealed or acoustic suspension speakers also typically have a -12dB roll-off, but typically not at 80Hz, making them a difficult match with the prepro.

On the other hand many ported speakers have -18dB, -24dB or even -36dB low frequency roll-offs that certainly don't combine with the prepros -12dB slope to produce a smooth symmetrical xover between the high-pass and the low-pass.

Just some of the gotchas in bass management.

I think another reason this is done is because too little sound in a particular frequency range is more acceptable than too much sound in it.

The problem is even with a particular roll-off slope, that different speakers roll-off starting at different frequencies. Speakers vary widely at where they start to roll-off.

I don't know what the Outlaw crossover slope is. Maybe it is as you suggest like other pre/pro's: where the low-pass gets a -24dB slope, and the high-pass gets a -12dB slope.

Will

[This message has been edited by Will (edited October 31, 2002).]

Will, if what you say is true, then why not implement a true symmetrical -24dB slope high-pass/low-pass electrical xover in the prepro. Doing it that way would provide a smoother match-up with a wider variety of mains and subs.

As you said the low frequency rolloff is all over the map for different types of main speakers, and this way would actually reduce the pollution of mains into the bass region much better than most current prepro's -12db electrical high-pass xover.

Another advantage is that a Linkwitz-Riley 4th order (-24dB slope) symmetrical xover actually SUMs to a zero signal level increase at the exact xover frequency as well as having a zero degeree phase offset. This is in contrast to other types of xovers with as much as a 2-3dB signal increase at the xover frequency and 90-270 degree phase offsets.

[This message has been edited by bstan (edited October 31, 2002).]

With a symmetrical crossover there's a greater chance of accidentally (due to room accoustics) hearing too much sound near the crossover point. They don't want you to hear overlapping sounds from different sounrces, at the crossover. At least that's my guess...

Will,


I don't happen to agree with this statement.

A -24dB L-R symmetrical slope would reduce output faster for the high-pass side than the current -12dB slope, thus reducing total SPL output below the xover frequency and thus interfering less with the sub's output, see below.

If you don't have a symmetrical crossover, then an SPL frequency sweep that starts below the xover frequency and continues above the xover frequency will not have a smooth SPL output because of the mismatched slopes causing SPL deviations below, at, and above the xover frequency.

You are right about room modes also influencing this smooth transition across the xover, but better to start with a smooth symmetrical xover SPL output response first and then correct for room modes only than to try and correct for both a mismatched xover and room modes at the same time.

Just one of my hypothesis on why bass management is so hard to truly get right for many people.

[This message has been edited by bstan (edited November 01, 2002).]

Phooey on me: there is a really good reason why crossover slopes aren't symmetrical, but I can't remember it. (I'll ask at HTF...)

There is no inherent problem with asymetrical crossover slopes. Most pre/pro/receiver manufacturers do it this way. I have seen many ruler flat room freq response curves with this kind of setup.

THX speakers with a THX crossover work. I think it's pretty much that simple - we inherited it from George Lucas.

One should set the xo point one octave above the netural rolling off of the speaker,this would make the speakers,accoustic roll off "slope" quiet irrelevant IMO.

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The Hun