How should I set my crossover?

[N8N]

Hi all,

First post here. Just finished wiring up my system today. I've had a 46" Samsung LED TV for a little while now, finally decided to match it with some sound. It's embarrassing, but I have had a Harman/Kardon stereo receiver that I bought used for something like $35 with a set of KLH bookshelves (I still think it was a good deal) when I was in college and that has been my sound system ever since, with new accessories added to it as new technologies came out. Well, anyway, I got a Pioneer VSX-921-K receiver and also a Polk RM6750 "speaker set in a box" off newegg because the stuff was on sale for a price that I couldn't turn down. (don't go nuts, the super-sales on both are over now... I caught the receiver on the last day, sadly.) I also ordered a pair of matching satellites refurbished from Polk's ebay store to use the full 7.1 capabilities of the receiver. For what I spent I couldn't be more tickled with the sound, although I know it's not the best it could be. I'm thinking of adding a PS3 for gaming and CD/DVD/Blu-Ray playback, and I already have a HD radio tuner coming (I know it's practically dead, but I am a NPR junkie, and ever since getting a HD receiver for my pickup truck I've gotten used to noiseless radio - and my roommate likes to listen to an AM sports talk station too which drives me nuts with all the AM static and lousy dynamic range)

Now to the question. I've got the sub wired to the receiver with an RCA cable and assume that the proper way to handle the installation is to crank the x-over on the sub all the way up and let the receiver handle the x-over. The Polk docs say to set the x-over at 120 Hz, but the only options I have on my receiver are 100 Hz and 150 Hz. I have it set at 150 Hz now and it sounds OK, but want to try 100 Hz to see if it sounds better (I assume that would help with imaging.) Do I run the risk of damaging my satellites/center channel if I do that? I've seen some online reviews mention using the L&R channels through the speaker level inputs to the sub instead of the RCA cable and claim that it sounds better, but wouldn't that lose any bass information from the center channel, and using the ".1" output be theoretically better?

Also, would upgrading the sub be worthwhile? It bothers me a little that on paper this sub only goes down to 40 Hz although in practice it is still so much better than anything I've had before that I'm still quite happy with it. Or would my money be better spent saving up for a better complete speaker system and planning on moving this whole setup into a secondary room eventually?

Thanks for any opinions or advice!

[MADGSF]

First welcome to the club!

I say try the crossover at 100Hz to see if you like the sound better but go easy on the volume and you should be fine. Since the sub has a finer crossover control than the receiver it might be worth the effort of running the speaker outputs through it. The -3dB point on those fronts is 135dB which is pretty high. When you start to crossover the sub that high you can start to hear dialog from it.

In regards to upgrades, be careful as this can be a slippery slope. The most important thing is if you are happy with the sound not what anyone else thinks! Not sure if you are in a house or an apartment but you might not be able to push the future system fully if you are in an apartment.

Having said all that my opinion is you would be better served saving up for a complete new speaker system. Sorry, it's not that what you have is bad but you will find the limits of those speakers quickly. You need speakers that reach down at least to 80Hz IMO and a better sub is great for movies. My suggestion if you want to upgrade is read, read and read. Then plan and make the big purchase once and by all means have fun.

[N8N]

I hear what you're saying... It's not the answer I was really hoping for, but kind of what I expected. Like I said, it sounds good for what I paid - I don't have an exact count but I think the final bill for everything except for the TV itself came in around $500 so I can't complain too much. I guess that this will end up being a secondary system someday which is really not the end of the world in the grand scheme of things. It does blow away my roomate's HTIB which make me happy :) (he's mocking me for spending "so much money" on home entertainment... little does he know what's out there...)

The real problem that I see is that if I wired up the sub through the speaker level inputs, then I'd need to add physical crossovers for all the surround speakers because as far as I can tell I can only set the crossover globally within the receiver. Or I'd have to upgrade all seven speakers at once, which ain't gonna happen any time soon...

I suppose as a stopgap, if I could find a sub that would go a little deeper but still doesn't roll off up to 150 Hz I could use that. But that might be asking too much of one device...

[MADGSF]

Yes you learn quickly that with any hobby one can spend as much as they want.

As for the using the speaker level inputs on your sub. If you want to do this on the receiver set the fronts to large, if your Pioneer is like mine that is full range, and set the sub woofer to off. This will ensure all low frequencies get sent to the front speakers. Leave the other speakers set to small and the receiver crossover at 100 or 150, whatever sounds best to you.

Set the crossover on the sub to about 130Hz. The sub woofer crossover will ensure you don't send low frequencies to the front speakers. Adjust both crossovers as needed for the best sound. Also try moving the sub and speakers around the room to see what sounds best to you.

[N8N]

Ah, that makes perfect sense, I will try that just out of curiosity. I have been using this system for about a week now and I have discovered one quibble with the subwoofer... it doesn't always turn on esp. if I am listening to a source without a lot of bass and at low volume (e.g. turn the radio on to listen to before everyone else gets up in the morning) and i have tried lowering the level on the sub and turning up the level of the pre-out on the receiver but it still does not turn on 100% reliably. I did drop an email to Polk CS yesterday but I haven't got a response from them yet (not meant as a negative, it is a weekend after all.)

Would a Polk PSW-10 sub be a significant upgrade? I think i could pawn this one off on my roommate (if the turn on thing were fixed) for his own system, but on paper other than more power and a larger woofer I'm not sure if it's a real step up (not much diff in frequency response) the only reason I'm revisiting this is that in my email this morning a certain online retailer onformed me that they're on sale for cheap...

[deronb1]

MADGSF had some great advice +1 on everything. Might I add that you might want to try setting the xover to 100hz, the fronts to "LARGE" and put the SW setting to "PLUS". This will allow full range to the fronts while allowing the sub to round out sound all of the time. Seems odd that there are only two xover options. Most AVRs go down to at least 80hz as that is the latest THX recommendation for HT.

[N8N]

MADGSF had some great advice +1 on everything. Might I add that you might want to try setting the xover to 100hz, the fronts to "LARGE" and put the SW setting to "PLUS". This will allow full range to the fronts while allowing the sub to round out sound all of the time. Seems odd that there are only two xover options. Most AVRs go down to at least 80hz as that is the latest THX recommendation for HT.

Sorry, I guess I wasn't clear. There are other options in the receiver for x-over frequency, but none between 100 and 150 Hz, which is what I was concerned with as I was initially trying to set everything up "by the book" as a starting point which was 120 Hz. I'll be ripping everything apart soon to put all this on a proper stand, and also get some proper cables to connect my "legacy" components to the receiver as opposed to the junk box mishmash that I have now so I will take the opportunity at that time to try rewiring the sub as you suggest and see if that makes any difference.