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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.
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almarg's avatar
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almarg
9,670 posts
 
If I didn’t prefer the Parasound, though, I supposed I could get an external crossover and have that feature with a different preamp — perhaps with more precision, even? That would allow me to get the preamp I like best *and* having the control a crossover gives.

If I have this wrong, or if adding a crossover is a complicated affair, please set me straight. This solution could be the one that splits the difference.


That’s certainly possible, of course. But the initial complication would be choosing an external crossover that would have minimal sonic side-effects while costing an amount that is reasonable in relation to the costs of the other components.

Some pro-oriented active crossovers can be had for less than $200, while other pro-oriented as well as audiophile-oriented models can cost many thousands. (The pro-oriented ones, btw, often provide only XLR and/or 1/4 inch connectors, rather than RCA connectors). I can’t comment on where within that wide price spectrum the sweet spot might be for your purposes.

Another possibility would be a passive crossover, perhaps constructed by yourself, consisting simply of a capacitor for each channel, an enclosure, and appropriate connectors. The value of the capacitor (i.e., the number of uF, or microFarads) would be chosen to provide the desired crossover frequency based on the input impedance of the particular amp that is being used. The main upside of that approach is of course low cost. The downsides include slow rolloff (6 db/octave), and the difficulty of determining what crossover frequency is optimal for the particular speaker and hence what the value of the capacitor should be.

Regards,
-- Al

cal3713's avatar
cal3713
1,421 posts
 
Thanks Al, I appreciate it.

To the OP, I'd also just like to note that Douglas is very right... given that your sub already has a crossover, you are completely fine without one. The Salk will play just like it was intended/designed without removing low frequencies and the sub crossover will allow you to integrate the two just as the sub was intended/designed to be used.

Again, as Douglas started, perhaps you'll be able to squeeze out a tiny bit more performance with a crossover, but honestly, I wouldn't worry about it at this stage. It might be fun to play with, or the process might drive you insane, but until you're thinking about pulling crossover components or building your own speakers, this is almost entirely academic.  I do still think (hope) the discussion is valuable and educational for you and future readers learning about these issues themselves...
hilde45's avatar
hilde45 OP
4,974 posts
 
@almarg @cal3713 @douglas_schroeder Q.E.D. as they say in logic. This clinches it for me. I do not want to start building crossovers, nor pay for expensive ones. I like the idea of keeping things simple. So, what I know now is this: the feature on the Parasound is not a gimmick, nor is it a necessity. It is a plus if and only if *literally* everything else for my ears is equal. I'm very happy with that answer and with the evidence for it. Thank you!
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