Need help understanding crossover settings for new sub

[27dnast]

Hello All,

I recently purchased an Energy S10.3 to replace a stock sub that came with a surround package (Polk Audio RM6750) that have. The frequency responses for the satellite speakers and center channels are: 100Hz-24kHz. The frequency response for the old Polk Audio sub was 40Hz-200Hz.

I originally had my old Polk Sub wired speaker level... in general, we were happy with the overall sound of our system. But, there were times where the sub would bottom out/distort. That wasn't good.

So, I purchased this 10" Energy Sub. It's FR is 21Hz to 120kHz. It has a built-in crossover feature that allows you to set the crossover as high as 110kHz.

I can't wire this sub speaker level... but I did purchase an LFE cable that I will be running out of my AVR. My plan is to set the crossover with the AVR... only, I'm not sure where to set the Frequency Response... and I'm beginning to wonder if this sub (based on the frequency response specs) is going to end up leaving a gap in some of the lower-mids. I say this because I have read that, typically, you set the FR to be 20Hz higher than the lowest out-put of your sats. But if I do that, that is the extreme high-end of the new Energy sub (where as the old polk sub went further into the mids at 200Hz).

So, my questions are: (1) Where should I set the crossover on my AVR.
(2) Do the specs say my new sub is a mis-match?
(3) can you set a crossover for the outer limits of a speakers output (e.g., can I set a crossover at 120 if my sub only goes up to 120).
(4) If I set my crossover lower (say, 110), what are the negatives and what should I listen for to know if something is wrong.

Thanks much in advance for helping out a newbie!

[tcarcio]

First welcome to the forum. As your speakers FR starts at 100 you should try and set the crossover in the avr as close to that as possible. But you need to either turn the subs crossover off or to the highest that it goes, that will stop the crossovers from causing problems. You should experiment to see what sounds best to you so you could try setting the avr crossovers lower,say 80, or higher, say 110 and play some bass heavy tracks so you can determine what sounds best. Also make sure all your speakers are set to small in the avr so your lfe will go directly to the sub. Again welcome to the forum and enjoy. Lots of good info here also....http://www.hometheatershack.com/forums/system-setup-connection/4083-setting-up-your-home-theater-101-a.html?highlight=setting+crossover

[tonyvdb]

TC is correct. I will add to what he said.
Sub's usually do not sound good if the crossover is set higher than 120Hz due to the fact that you end up with localization issues and you start to "hear" where the sub is and that is not a great idea. Placement of the sub may help, have you tried it in different parts of the room. Corner placement can usually give you a boost in db's.
You need to remember that even though the frequency response of your mains go down to 100Hz this is not a brick wall and there will still be output below that just not as much. You should be fine with setting your crossover at 100Hz.

[27dnast]

Thanks for the responses, folks. Question answered... I'll put the advice to work this afternoon and let you know of the results.

Question: would an array sound file such as the one of the ones under section 2 (Sine Sweeps) from the following website, be useful?

Also, my avr has a MCACC program... I'm guessing that main makes sure that the sound from each speaker is reaching the main listening position of the room at the same time (correct?).

Thanks!

[tcarcio]

I don't know about question one but I have an elite reciever with MCACC and you are correct. It eq's the sound with the mic in the listening position but you can choose to use multi point eq. It will explain details in your manual but it really is more geared to eq'ing a larger listening position because you move the mic to 3 different positions dureing the process. I run the system this way and it works well for me. There is alot of info on this here....http://www.avsforum.com/avs-vb/showthread.php?t=1112470

[drdoan]

Welcome bitx. Have fun. Dennis

[27dnast]

Just an update... so some things have happened on my end with the set-up. First off, I successfully ran wires in walls to complete a 7.1 set-up. The new rear-surrounds are really cool and add a great dimension. Unfortunately, my now "rears" are probably more to the side of the room than they should be... but there's not a whole lot I can do with that unless I were to tear into some walls (and I'd also have to splice some speaker wire... not really interested in that). So, my rears used to face fairly straight forward (they are mounted close to the ceiling). I've now angled their orientation inward. My surround rears are mounted about 1 1/2 feet above head level and are oriented directly to the primary listening position. I've played around with their orientation and found that angling them inward allowed the sound to sweep across the room the best... if that makes any sense.

So. On to the subwoofer and crossover questions. My first surprise came when I found out that the crossover settings available on my AVR are 50Hz, 80Hz, 100Hz, 150Hz, and 200Hz. No 120. Hmmm... this receiver is the top Pioneer model (at least when I bought it...)... I'm guessing that, much like my Pioneer PDP, you need to buy into their Elite model line to gain more control over outputs. Oh well. I was disappointed though because a 110Hz crossover was going to be a sweet spot for me (considering that my sats are small and only have 3.5" cones and my new Energy s10.3 sub has an upper FR of 110Hz)... Upon my first listen it became evident that there was something missing in the lower mid-ranges. They set-up sounded unusually bright... I like bright but this was too bright... and the lows sounded out of place. I hooked-up my old Polk sub and voila... my those missing mid-ranges came back.

So, I have developed answer. 2 more subwoofers. What? You say? Well.. yes. There are now 3 subs in the mix. I ended up picking up some Polk PSW10 subs (these subs have a FR of up to 200Hz... I selected them because they go much more up into the mid area that my new energy doesn't even touch). I have one sub wired speaker level to the front L/R speakers... and the other sub is wired speaker level to the center channel. Have set their crossovers to be 120Hz. I have also set both the L/R speaker and center channel speaker outputs to be SMALL. And the new Energy Sub (receiving input via LFE from the AVR) has a crossover point of 80Hz. So, in essence, my AVR is piping the mids and lows (for my front channels) between 80-120Hz to the two new Polk Subs. Everything below 80Hz is going to the Energy.

The results? Generally pretty awesome! That's good news, right? The mids are back in full force. My new Energy sub is thumping away and hammering out lows with ease (the lows that I never had before)... and a surprising (well, I guess this shouldn't be too surprising) result is that my center channel has a depth and life that I've not heard from it. Voices in the dialog sound much fuller and vibrant.

Who knew?

The only unfortunate down side that I can see, is that my rear and rear surrounds now have a gap between their spec low of 100Hz and the frequency crossover on the energy sub (80Hz). I'm guessing that gap... primarily because of limitations of my smaller sat speakers... is probably a bit bigger. But, seeing as those rears are only in the periphery of the sound field, I'm okay with it.

I know some of you will wonder why I didn't just invest more money into bookshelf L/R speakers and a larger center channel... but I think I'm making out okay. Perhaps I more or less put a band-aide on my system... but I think it sounds pretty good. Outside of the 3 subs (which, while big, look rather imposing... which isn't a bad thing), I've maintained the minimalist approach to my set-up and I've been able to keep my RM6750 sats, which I actually like a lot.

Thoughts?

[tonyvdb]

I've maintained the minimalist approach to my set-up and I've been able to keep my RM6750 sats, which I actually like a lot.

Really thats the bottom line, if your happy with how it sounds then that is all that matters.
We all make sacrifices weather its acoustics, room size or just how much one can spend.

[GregBe]

I personally wouldn't worry about the gap in the surrounds. It sounds like you did a good job blending your fronts with the subs. That BY FAR is much more important.

[27dnast]

Phew. Well, I was concerned that someone was going to tell me I've broken an obvious speaker set-up rule.

Just for curiosity... what would happen if I wired my 4 surrounds speaker level to two more subs stacked in the rear of the room?

That would make a total of 5 subs...

I know that speakers start becoming directional at about 120Hz.... would one then wire the Right Surround and Right Rear to one Sub and do the opposite on the other side of the room?

Oh well... I really don't have the space for something like this... and the chances of me getting my wife to agree to two more sub purchases: not very good . Although she has been a sport through this...

One thing I have learned is that this Energy s10.3 sub is rocking the house. Our dedicated theater room is in basement below the kitchen... and last night the lows were rattling the kitchen cabinets.

A small price to pay.