DYohn
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Post by DYohn on Sept 18, 2021 13:57:55 GMT -5
Hi Boom. Yes, I know full well how a 2.5-way system works. Would you like me to design one for you?  I thought you had said your external Xover was set to 250, my mistake. If it's at 90 then you should be fine and no, it is much easier to use your stand-alone Xover as a 2-way, which in effect provides the sort of bass management a HT processor provides. You COULD run full-range to the mains and blend in the subs at the point where they are needed - I do that all the time in music systems with excellent results. But it is not simple and requires in-room FFT measurements to do it correctly. The solution you are using with an external bass management Xover is far simpler. As to your 5 points, here's my opinions: 1. This is moot. It is not a significant thing to worry about unless you are using flea-watt amps. 2. This is maybe correct, maybe not, you simply cannot make a blanket statement like that. Have you measured IMD? 3. You would not do this unless the phase and Xover slopes were used properly in the first place. Like I said, it is not simple. 4. Again, this is simply speculation and not at all the case. If a system is properly set up this becomes entirely moot. 5. Why do you say this? What EQ are you applying? I do not understand this comment. |
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Post by Boomzilla on Sept 18, 2021 15:23:07 GMT -5
Hi Boom. Yes, I know full well how a 2.5-way system works. Would you like me to design one for you? I wasn't questioning your understanding, only trying to explain better how the speakers were designed. I thought you had said your external Xover was set to 250, my mistake. If it's at 90 then you should be fine and no, it is much easier to use your stand-alone Xover as a 2-way, which in effect provides the sort of bass management a HT processor provides. You COULD run full-range to the mains and blend in the subs at the point where they are needed - I do that all the time in music systems with excellent results. But it is not simple and requires in-room FFT measurements to do it correctly. The solution you are using with an external bass management Xover is far simpler. Since I lack a Fast-Fourier Transform analyzer, I think I'll stick with the crossover. As to your 5 points, here's my opinions: 1. " The satellite amplifier has to work significantly harder because it now has to reproduce a significant amount of bass that it previously didn't." - This is moot. It is not a significant thing to worry about unless you are using flea-watt amps. Agreed 2. " Intermodulation distortion of the satellite speakers increases exponentially because of the greater excursion required of the bass/midrange drivers (this would be less were the system a true 3-way)" - This is maybe correct, maybe not, you simply cannot make a blanket statement like that. Have you measured IMD? I have not, but I've read this same thing for years and years from multiple and credible engineering sources as well as audio magazines. It DOES make sense since IM distortion is a direct consequence of the same transducer simultaneously reproducing multiple tones. The tones do modulate each other and the greater the transducer excursion, the greater the modulation. 3. " Unless the phase is set right for the slopes involved, there can be significant cancellation at the frequency where the satellites begin to roll off and the subwoofer blends in - You would not do this unless the phase and Xover slopes were used properly in the first place. Like I said, it is not simple. It isn't simple, which is why for the average audiophile, it's better to use a symmetrical (or at least same-order) crossover at least an octave away from the speakers' natural acoustical rolloff. Otherwise, the acoustic roll off of the driver/enclosure must be included in the crossover calculation. 4. " Unless the subwoofer's plate amplifier uses a steep low pass filter (minimum of second or third order), the sub (with significantly more distortion than the satellites) will continue to sing along above its crossover point, muddying the bass of the satellites." - Again, this is simply speculation and not at all the case. If a system is properly set up this becomes entirely moot. The crux of your argument is "if a system is properly set up..." If one is using a commercial crossover, the high-pass leg is usually set up at 12dB/octave (second order) and the low-pass leg is symmetrical. But even 12 decibels down is audible. The "best" crossover I've seen used a combination of first and third order filters. The high-pass was first order (6dB / octave) while the low pass was third order (18dB / octave) to keep the subwoofer's distortion from muddying the mid bass and to keep the crossover region in phase. 5. " Any equalization applied in the bass will now affect the satellite speakers as well. With the crossover active, sub equalization could be applied only after the crossover, and could not possibly affect the satellites." - Why do you say this? What EQ are you applying? I do not understand this comment. I apply DSP and sometimes analog EQ to the subwoofer feed only. This is used to flatten the sub response and to slightly extend its bass extension. If I apply this equalization post-crossover, then the satellites are isolated from any equalization I apply. However, if I ran the satellites full-range, and had no discreet subwoofer feed (tapping the full-range outputs instead), I'd need to apply all equalization to both the satellites and the sub(s). Or not - I could use Y-adapters, and then apply EQ to the sub feed(s) only. So you're right, this one is moot. Cordially - Boomzilla |
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DYohn
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Posts: 18,487
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Post by DYohn on Sept 18, 2021 17:26:22 GMT -5
Look, I'm not making any argument. I'm simply stating what I know after years of experience. You should, of course, do whatever it is you think you need to do. It's what you always do anyway. Hang the diffuser from the ceiling in the first reflection point. |
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