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Is Parasound on to something? Or, How important is crossover management in preamps?

How important is crossover management in mid-fi receiver?

I auditioned Parasound separates yesterday — P6 and A23+ and the dealer emphasized how useful it would be to be able to control the crossover *both* for the subwoofer (I have a Rel 328) and the bookshelves (TBD, but I'm looking at Dynaudios and Salk WOW1's). Not many preamps have this, and I'm wondering how important it is. I'm also quite interested in PS Audio's separates (Stellar Gaincell + S300) but they do not have these, nor do they have tone controls.

So how valuable is Parasound's controls? What is the significance (positive or negative) control over the crossover — especially of the *main* speakers themselves? The positive, I read, is that it (a) allows mains to do a more precise job by relieving them of the burden of the bottom end, and (b) it increase the efficacy of the power amp in driving the mains. Is there a negative? Is there something "improper" about limiting the demands on mains, especially given their designed frequency range?

As you can see, the answer to this question helps determine whether Parasound has a major value-adding feature in these crossover controls.

Obviously, at the end of the day, auditioning pre's and poweramps (or integrateds) is crucial, as is match to speakers, etc. But if this feature is very important for fitting sub and mains together — and fitting speakers to room environments — then it will help me weigh the Parasound or any other preamp with this feature.

P.S. To those who keep seeing my newbie questions, I hope they're not irksome. I'm posting so often because I'm researching purchases for a whole system, of some cost, and so I'm really digging into these questions about all aspects. And I'm having a blast.
128x128hilde45
hilde45's avatar
hilde45 OP
5,091 posts
 
Here's the take from PS Audio sales. I asked them why their stuff didn't have what Parasound did.

The reply: "We believe handling the crossover is actually detrimental to the sound quality. When a speaker designer finalizes a design for a speaker they have typically done so very carefully. A large part of this process is the crossover itself. So it’s a little bold to believe we can set a better crossover point than the person who designed it."

So, I'm surprised that Parasound, which gets good reviews and seems well-respected would do something so detrimental to the sound quality. Seems gimmicky and non-audiophile to do that. 
cal3713's avatar
cal3713
1,421 posts
 
Someone has to control the crossover point.  As you pointed out above, it can be convenient to have the option in a preamp, but it's also more circuitry that could be done better with a separate component or within the speaker itself.  I don't see any sense in which it is wrong, and certainly there are some situations/gear in which it could sound better than not using it.  If not, why would they ever have put in the feature. 

Hell, if you really want to control the crossover you can put a Pass Labs XVR1 after your preamp, buy the gear to biamp/triamp and then pull all the inductors/caps/resistors out of your speaker and connect your amps directly to the drivers.  That'd probably sound better once you find all the correct crossover values and levels, but it would potentially double the cost of your system and you'd have to spend many many hours working with the XVR settings.  A first order crossover?  Second?  Fourth?  How many poles do you want in your LP filter?  Plenty of people do that, but they're mostly over on DIYAudio, not here on Agon.  
djones51
4,947 posts
 
What did you think PS Audio Sales was going to tell you when you asked why they didn't have the features the Parasound did? If you use a sub with small monitors you need some way of sending the low frequency to the sub and the mid/ high to the monitor there might be better ways than having it in the preamp but unless you want to spend more money and time using crossovers in the pre is effective. 
hilde45's avatar
hilde45 OP
5,091 posts
 
@cal3713 Good points. The only other reason they might have put the feature in, besides the one you state, is that customers demanded it, despite the effect on sound quality. What I'd like to find out from them, is whether they believe they've pulled it off in a way that makes a minimal/negligible impact. And you're right that I don't want to go that crazy with DIY audio! I'm just trying to determine whether this feature is important — all other things being equal — contingent upon the effect is on sound quality.

@djones51 I suspected they'd say something defending their product (of course!) but I didn't know what they'd specifically say. Also, I am a charitable guy; they might have had some additional reasons I had not considered. Instead, they made an argument based on not messing with the speaker's design, as if every speaker's design would contribute to all rooms, uses, components, etc. If folks here are right, that is specious reasoning. The fact they committed that to print tells me something (maybe not much) about the company more generally. It helps with my purchasing decision.
cal3713's avatar
cal3713
1,421 posts
 
I don't think PSA's argument is specious at all.  When you change the crossover point, you really are arguing with the speaker designer.  Not that the Parasound feature is likely to be used for anything other than sub integration.  It's also a rare feature, so I don't think PSA was being defensive at all.  Most subs are active and come with a built in crossover that allows you to integrate with your main speakers, so sending them a full signal is normal and expected.  The passive ones expect you to pair them with a subwoofer amplifier that also has gain and crossover controls, also expecting a full range signal.  In both of those cases skipping that circuitry (which is probably coming from a $200 plate amp) and relying on the Parasound probably will improve the crossover quality.
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