RM6700 & PS404 crossover settings

Mtnsummit

Excuse me if this has been answered elsewhere in the forum, but I could not find an answer in my search-

I recently purchased the RM6700's, and added the PS404 Sub. I have purchased a Harman/Kardon AVR525 receiver, and in the set up process for the receiver, I need to tell the receiver what the crossover points are for the speakers - The Center, F/L Speakers, Surrounds, and the Sub. The manual says I need to set these in "HZ", example "100HZ". I find the polk manuals explaining the "crossover" is "3KHZ". I am not sure how to convert this number to what my receiver is looking for (In other words, what would a 3KHZ be equivalent to in HZ's?). Any help appreciated.

If this helps explain my receiver, evidently the receiver, by allowing the user to input above items, can allow a user to mix different speakers/brands and handle the acoustics accordingly.

Thanks again for any help - some of this stuff is greek to me

John

Dr. Spec

For the RM6700, a 100 Hz filter point will probably work best, maybe even 120 Hz.

Set all the speakers to small and all the filter points to 100 or 120 Hz. Set the subwoofer to on/yes. Run a sub cable from the h/k sub pre-out to the 404 LFE Unfiltered input jack.

Set the h/k sub speaker level to -5 and adjust for preferred bass volume with the 404 volume control.

Getting an SPL meter and balancing all your speaker levels will help greatly.

Doc

burdette

Originally posted by Mtnsummit
The manual says I need to set these in "HZ", example "100HZ". I find the polk manuals explaining the "crossover" is "3KHZ". I am not sure how to convert this number to what my receiver is looking for (In other words, what would a 3KHZ be equivalent to in HZ's?). Any help appreciated.

As for this question, there are 1000 hertzeses in 1 kHz... the 'k' is the metric multiplier 1000, such as kilometers is 1000 meters, kilograms is 1000 grams, kilofart is 1000 usual farts, and 3kHz is 3000Hz.

In contrast, 'milli' is the metric muliplier 1/1000, so there are 1000 millimeters in a meter, 1000 milligrams in a gram, etc.

Be wary of kilobeergoggles.

GuitarheadCA

kilofart is 1000 usual farts

Roflol

Dr. Spec

Do not confuse a true crossover with a high/low pass filter for bass management. Many manuals do interchange the two terms and technically it's wrong and can be confusing as you have found out.

Doc

Mtnsummit

Thanks for all the quickposts! You guys (or gals) are quick. A few more comments/questions if you do not mind, based on your comments above -

For clarification (I am home now to post) - My receiver manual describes my initial question in this thread as follows: "You now have the option to take advantage of the AVR525 Triple Crossover System. The low-frequency crossover point is set by the design of your speakers. It is defined as the frequency which either the lowest possible frequency the speaker is capable of reproducing, or the frequency at which sound is sent to the speakers internal low-frequency driver, as opposed to the mid range driver." "Before making any changes to the settings for the crossover point we suggest you find the crossover point for the speakers."

In looking at the specs that came with my Polk's, the small speakers (RM 2350)"Crossover" spec is listed as "3.1kHZ", same for center speaker (RM 2650). These are packaged together as RM6700's.

In the specs are listed "-3db limits: 130Hz-20kHz". What the heck does spec mean?

Doc - you mention to perhaps try a setting of 120Hz - A stupid question - how will I know or "detect" if the 100Hz or 120Hz is a better setting? I am not an audiofile by any means, and mainly have gone through all of this to get great sound from movies.

Lastly, I have initially set up my RM6700 speakers per the manual recomendation, which is to say run the Front speakers thru the sub PSW404, then from that speaker run the front speaker wires into the receiver. I have told my receiver I do not have a sub attached, per instructions from Polk manuals.

My reciever of course says to run a sub cable from receiver to sub. It also notes "The available choices at which point low-frequency information will be sent to the subwoofer, rather than to the main speaker channel, are 40Hz,60Hz, 80Hz, 100Hz, 120Hz, and 200Hz." "If an exact match is not possible, pick the closest choice that is above the speakers low-frequency limit or crossover point to avoid the creation of a low-frequency "hole" where your system will have no bass information."

Given the above, should I still hook up the sub cable directly from the receiver to the sub, or go with the Polk recommendation from manual and avoid the sub cable? Perhaps all of my giberish in above paragraph makes no diff?

And thanks for the SPL meter note - I bought one on the way home, just have to figure that one out now Is it OK to use the tones supplied with the receiver, or should I get some "audio disk" to give me the tones to set the speaker levels?

Ok - enough said - sorry for the long winded message - thanks again for this forum!

John

Equipment -

Speakers: RM6700 set (RM 2350 Satellites plus a RM 2650 Center)
PSW404 Sub
Receiver: Harman/Kardon AVR 525
DVD: Toshiba SD-4800
TV: Toshiba 55HX70 55 inch projection

Dr. Spec

Notice how the -3dB point of your speaks is 130 Hz?

You want to start using the sub around there because that is the frequency where your speakers start to trail off and can no longer produce sounds at the same volume as they can at higher frequencies.

This is where I concede to the Polk method being as good or even better than the sub cable method since the filter on the sub can be set to transition from the RMs perfectly.

If you still want to go with the sub cable, select 120 and set up as I advised above.

As for the test tones. The internal ones are fine. Set the meter on C-weighted slow on the 70 dB scale and place it exactly where your head would normally go, facing forward and angled up a bit.

Set the Master Volume to 00 and start the test tones. Adjust each speaker level setting so the meter reads exactly 75 dB.

You can only set the sub level with the cable method. If you use the Polk method, adjust the sub by ear.

For the cable method, set the sub level to -5, and run the sub test tone (still at Master Volume 00) and adjust the 404 volume control so the meter reads about 78 dB.

Doc

Mtnsummit

Thanks Doc for all the great info!

burdette

I'm gonna bite on this one, Doc...

Besides the obvious that "filter" tends to be one-sided (e.g. high frequency filter rolls off the highs, low frequency filter rolls off the lows), and crossover tends to be two filters combined to control the frequencies sent to two separate drivers...

...from your persective and the comment you made... the difference between a crossover and a filter is.... ???

Dr. Spec

Originally posted by burdette
I'm gonna bite on this one, Doc...

Besides the obvious that "filter" tends to be one-sided (e.g. high frequency filter rolls off the highs, low frequency filter rolls off the lows), and crossover tends to be two filters combined to control the frequencies sent to two separate drivers...

...from your persective and the comment you made... the difference between a crossover and a filter is.... ???

Sorry I almost missed this one burdette.

Obviously, crossovers are filters made from HPFs and LPFs. They divide up the frequency spectrum into the various frequency ranges (bands) needed by the drivers. Crossovers provide high and low frequency bands for two way systems, and high/mid/low frequency bands for three way systems.

I didn't mean to convey that a speaker crossover and a filter were two different things from an electronics standpoint. They function identically.

But as you can see from Mtnsummit's statements, the ubiquitous use of the generic term "crossover" tends to confuse newbies when they are trying to understand bass management as opposed to full range signal management.

To avoid confusion, I prefer to use the term "crossover" as it relates to management of a full range signal being inputted to a conventional speaker. Conversely, I prefer to use the terms HPF and LPF in conjunction with the specified single frequency and the slope rate(s), when discussing digital bass management.

But what you are implying is correct - crossovers are nothing but a bunch of HPFs and LPFs.

Doc