Crossover recommendations

kevindef

I just received my new Polk speakers for my front and center:

RTi A7

CSi A6

and also have

DSW Pro 600

I am also using a pair of RM 8' for my surrounds and a pair of RM 8's for my rear surrounds. I would like to replace the RM 8's in the near future with 4 FXi 6's, but for now I will live with the RM 8's as my surround speakers.

Now getting to my question. I am setting up the the crossover etc on my receiver and am wondering what I should set the crossover for each of the speakers. Here is the frequency of each:

RTi A7: 20Hz - 27Khz

CSi A6: 45Hz - 27Khz

DSW Pro 600: 20Hz - 160Hz

RM 8's: 95Hz - 24Khz

I just set the crossover for the 2 fronts and center at 80. Being that the RTi A7's can go down to 20, should I make that number lower? Something different???

My receiver can be set in increments of 10, from 40 - 200 for Fronts, center and surrounds

How about the center? Should I go 50 with the CSi A6? Something else???

Now the RM 8's. The receiver selected 160 for these, but I thought that was way off. How is 100? Or should it be 160? Anything different?

I know this can depend a lot on the room and personal tastes, but I would like to get as close as possible to being in the ballpark and then just fine tune. Thanks for any help!!! Kevin

CRESCENDOPOWER

Personally, I would run everything full range, and cross your sub over somewhere below 65 hertz. See how your receiver handles that application, and get back to us.:)

GTB

A recommended starting point is to set all speakers to small and crossovers to 80hz.

Then tweak.

I ended up with my fronts and center (RTi8s and CSi5) set to small, crossover set to 60hz. Rears (Monitor 40s) I left alone, they remain at 80hz.

Not only does a sub add fullness and that wonderful bottom end to HT and music, it also unloads the receiver's amps for cooler operation and allows the speakers to open up to the mid frequencies and above.

kevindef

Right now I have everything set to small with the fronts and center set to 80 and the surrounds to 120. I haven't had a chance to see how that will sound. Thanks for the help!

CRESCENDOPOWER

GTB wrote: »

A recommended starting point is to set all speakers to small and crossovers to 80hz.

Then tweak.

I ended up with my fronts and center (RTi8s and CSi5) set to small, crossover set to 60hz. Rears (Monitor 40s) I left alone, they remain at 80hz.

Not only does a sub add fullness and that wonderful bottom end to HT and music, it also unloads the receiver's amps for cooler operation and allows the speakers to open up to the mid frequencies and above.

Absolutely, and I knew that a polar opposite view would come across. There is a reason for the filtering on many home-theater receivers. There is also a reason for external amplification to avoid the downfalls of the filtering. When on a budget the filter option is all right, but to obtain fullness throughout running amplification that can actually drive enough of the 7 loudspeakers to reduce the load on the primary receiver requires a very special multi-thousand dollar receiver, or at least some type of external amplifier.

lmacmil

kevindef wrote: »

I just set the crossover for the 2 fronts and center at 80. Being that the RTi A7's can go down to 20, should I make that number lower? Something different???

My receiver can be set in increments of 10, from 40 - 200 for Fronts, center and surrounds

There was a pretty detailed, technical post in the theory section of AVSForum in response to a question I posted that was similar to yours. The gist of response was let the sub do the "heavy lifting" below 80hz because even if your speakers have specs that say they go below that, in order to reach loud volumes they will probably be distorting heavily or bottoming out the woofers.

gp4jesus

I posted this to another thread w/similar question.

I'm from the old school of subs, bi-amping, etc. I've bi-amped, tri-amped, even quad amped for several decades, long before this HT stuff developed to what it has. I'm glad decent powered subs can be had quite inexpensively; ones w/f3 below 35hz for a bit more. 20 years ago a decent passive sub cost more than many powered subs today and powered subs were real pricy

To echo what GTB said: set ALL channels to small. Even w/the A7 f3 @ 35hz*. I would set XO to 100hz and tweek from there. Read on for more background about 100hz.
*read the specs carefully

Listen to just the speakers, (e.g. center alone, mains alone, etc) for which you're trying to adjust cut off. Take your time, listen loud and soft, w/and w/out the sub, using different source material. I've read and agree: "don't try to tweek more than 2 hours at a stretch" or "quit when your tired." Been there, done that. Took one night to swap my old Rotel for a new(er) one. Took 2-3 hours-I have 5 sources and 4* outboard amps. Began "set-up" the next.
* adding a 5th and changing one existing soon

Back in the day 110 hz was the "ideal" frequency to, read this carefully, to improve midrange performance! W/out question most subs will outperform most full range speakers below 70-80 hz, and shine below 50 the way fullrange just can't. Add to that a separate amp w/its own power supply, handles the, in the words of lmacmil, "the heavy lifting," lightning the load for the other channel's amps. I've heard people using tubes above the cutoff and transistor w/what many believe it's superior damping below cutoff.

Just because a speaker CAN "produce" a given freqencey w/in some range (e.g. 50-20K) it does not mean it does well at it's extremes. Those surrounds with an advertised 95hz low point probably does well to 125 hz. below that distortion goes up faster than Dow jones drops on a bad day.

Other points overlooked by many:
A powered sub's amp, driver, and power supply* are engineered to work together usually producing a flatter low end w/greater output and extension than most pasive full rangers
Everything being "equal," halving a given frequecy demands 2-4 times the power. Yeah 50 hz requires 2-4 times that of 100 hz.
* another overlooked point

That's why in a big PA system you see 4-10 as much power for "the bottom end," with the "numbers" going down as frequency goes up. "Everything being equal," Highs, not the tweeters, need just 5-20 watts that, from 250 hz and below, would need anywheres from 5-15 times the power to produce equal output in decibels.

hope this helps & happy tweeking!

Conradicles

When you run the room EQ on the receiver with the set-up mic, what does it tell you to do?

rallyshark

I say run the fronts and center at 80hz, and the RM8s at 120hz or higher even. Your receiver made a pretty good "guess" on those. The RM8s may produce 95hz, but that's really out of their comfort zone...FWIW, my receiver set them to 140hz back when I was playing with a set. Hell, I'm only running my OWM5s down to 100hz even though their frequency response is a good bit lower. They just start to fall on their face below 100hz. I hope that helps, and nice speakers!:)

kevindef

Thanks for the help everyone! Right now I am real happy with the RTi A7's and CSi A6. I have those set at 80. I have the RM 8's at 100 but will give them a shot at 120. When I ran the auto calibration with the setup mic, the receiver set the surrounds to 160. I will run that again and see what it does with the fronts and center. I don't remember what crossover settings it set for those. Although, I do remember they were set to large and I changed them to small and then the crossover to 80. I am starting to think that I should just replace the RM 8's with either the RTi A3's or FXi A 6's, but I have spent WAY too much the past few months on this "hobby".

gp4jesus

"The RM8s may produce 95hz, but that's really out of their comfort zone..."
ditto rally shark
"...below that (125hz) distortion goes up faster than Dow jones drops on a bad day..."
tony

lmacmil

kevindef wrote: »

I am starting to think that I should just replace the RM 8's with either the RTi A3's or FXi A 6's, but I have spent WAY too much the past few months on this "hobby".

Maybe you've reached that famous destination called "enough."

Before you run out and spend $400 or more on a pair of surrounds, consider either new RTi4s from Ebay sellers at around $200, new Rs or Ts or Ms at $180, or refurbs from the Polk Ebay store. Or just live with your RM8s for a while and see how much (or how little) sound actually comes out of the rear speakers.

gp4jesus

Listen to what you have for now. In the meanwhile do some shopping on ebay. get a feel for what's a deal for what you have in mind. You can find some deals on ebay; I bought my refurbed CSiA6 from Polk on Ebay, about $200 I think;about the same for a pair of RTi A1s.
Other people selling RTi A series suff at good prices

cheers tony

gp4jesus

Kevindef: Let me provide you w/relief up front by saying, take heart that all* rear channels don't have quite the volume or bass demands of the fronts (LCR/Sub).
*5/6/7.1

I just checked the polk site to learn RM8's have 2 1/2" LF drivers, w/a 130 hz f3. Armed w/this info I'd start at 120 hz and "go up" from there.

It takes a lot of engineering (read that $$) for small drivers to overcome what makes bigger drivers have an easier time to produce low end, especially below 50hz.

w/ few exceptions (see $$ above) the smallest LF driver I'd cutoff at 100 hz* is a 5 1/4 depending upon the f3, not the "overall frequency response**" low point. Back in the mid-80's had pair of Radio Shack speakers w/ 20 watt 4" woofs. Cranked up a Steeley Dan CD through them just to see what they could take. little by little I turned up the volume; turned up the bass control a bit too. after about a LOUD hour of watching those cheap*** woofers get sucked in and pushed out of their enclosures w/some clean, serious power one woofer blew!
* I realize there are exceptions and others will have different opinions
**from Polk's site
*** $10 replacement

Another way to think about it-a given LF driver might need to produce 35-5Khz to have a sweet spot between 60 hz and 2K. If you band limited your listening to above or below the sweetspot it would sound like "death warmed over."

So take heart in your decision! cheers-tony