Best Crossover frequency for Sub

[BlueThunder]

Hi All,

I have my surround sound system set-up and running this week.

Receiver - Pioneer VSX LX70
Speakers - Monitor Audio (RS6, RSLCR, RSFX, RSW-12)
http://www.monitoraudio.co.uk/range.php?range=2


I am wondering what crossover frequency to use for the Sub. Most advice and THX seems to recommend 80Hz. This is for movies 5.1 and stereo tracks expanded to the rears)

When it is set to this the front L/R speakers to 80Hz they seem to be under worked. The front R/L are tower speakers and have a tweeter, mid range and bass speaker.

When I set it to 50Hz the front L/R seem to delivery a more balanced sound and appear to be comfortable in doing it, but also the surrounds are now working a lot harder (2 tweeters and 1 bass/mid range)

What to you thing the best setting is. If it is 80Hz do you think that the large front L/R are an overkill and I should have went for the smaller option .

Really appreciate you help on this. I will try to add a picture of my set-up later today.

[bleedsblu]

Originally Posted by BlueThunder

Hi All,

I have my surround sound system set-up and running this week.

Receiver - Pioneer VSX LX70
Speakers - Monitor Audio (RS6, RSLCR, RSFX, RSW-12)
http://www.monitoraudio.co.uk/range.php?range=2


I am wondering what crossover frequency to use for the Sub. Most advice and THX seems to recommend 80Hz. This is for movies 5.1 and stereo tracks expanded to the rears)

When it is set to this the front L/R speakers to 80Hz they seem to be under worked. The front R/L are tower speakers and have a tweeter, mid range and bass speaker.

When I set it to 50Hz the front L/R seem to delivery a more balanced sound and appear to be comfortable in doing it, but also the surrounds are now working a lot harder (2 tweeters and 1 bass/mid range)

What to you thing the best setting is. If it is 80Hz do you think that the large front L/R are an overkill and I should have went for the smaller option .

Really appreciate you help on this. I will try to add a picture of my set-up later today.

I'm afraid the best answer is 'use your ears'.

I would say leave your fronts at 50hz, and slowly bring in your sub (while listening to some bass heavy material) and find where they blend best. If you find that when you bring up the sub and the bass actually sound 'weaker' or 'less defined', switch the phase on the sub (if this isn't an option, you may have it available on the receiver, or worst case..have to move the subs position forward or back in relation to the fronts)

Hope this helps.

[Blu-Dog]

Originally Posted by BlueThunder

Hi All,

I have my surround sound system set-up and running this week.

Receiver - Pioneer VSX LX70
Speakers - Monitor Audio (RS6, RSLCR, RSFX, RSW-12)
http://www.monitoraudio.co.uk/range.php?range=2

Very nice speakers - almost got a set myself. Never heard their sub, though.

Originally Posted by BlueThunder

I am wondering what crossover frequency to use for the Sub. Most advice and THX seems to recommend 80Hz. This is for movies 5.1 and stereo tracks expanded to the rears)

When it is set to this the front L/R speakers to 80Hz they seem to be under worked. The front R/L are tower speakers and have a tweeter, mid range and bass speaker.

When I set it to 50Hz the front L/R seem to delivery a more balanced sound and appear to be comfortable in doing it, but also the surrounds are now working a lot harder (2 tweeters and 1 bass/mid range)

What to you thing the best setting is. If it is 80Hz do you think that the large front L/R are an overkill and I should have went for the smaller option .

Really appreciate you help on this. I will try to add a picture of my set-up later today.

Go with 80Hz if possible - you have a situation you may not be aware of yet.

Your RS6's are power hogs. They really pull down the juice. The reason I didn't buy them is that I was given an unfair listening test; I heard them on a 100 watt receiver in the sound room, a Pioneer that is supposed to be pushing 8 ohm speakers.

Your RS6 units are rated at 6ohm, 120 watts RMS. Once you hook up the center and surrounds, you're getting nowhere near that kind of juice to the towers.

So they'll sound a bit weak, especially pushing the big hard-shell woofers on those guys. It takes a lot of power to get sound out of a stiff diaphragm like on the RS6 - which I didn't know, and bypassed them for a pair of Vienna Acoustics. I wound up buying a power amp, which I would have needed for the MA's, anyway - but we live and learn.

They will sound much better at high volume, really pushing the power. Unfortunately, this will really put stress on your receiver. I like the LX70, but it's a 100 watt receiver, rated at 8ohms, and it will get very tired at high volume on 6ohm loads. At lower volume, it simply doesn't have the reserve power to drive the bigger speakers, as it divides the power from a single transformer across all channels.

The Pioneer Elite series has a very nice customizable interface that allows you to boost the DB level for individual channels. It's really just a stopgap in situations like this, not a solution. For speakers rated at 120 watts RMS, it doesn't sound right that you need more power - but you do, at least for the big fronts.

A simple test: disconnect the surrounds and center channel, and play in normal stereo mode without the sub. Set your volume at midpoint (pushes them a bit). See if you get any distortion, buzzing, etc. Play it for about ten minutes at this level, and see if the receiver begins heating up. Then connect your sub, select a 5.1 mode that is not center-heavy, and try it at both the 80Hz and 50Hz settings. Again, keep the volume fairly high - you want to power those speakers strongly, driving them with no other load.

I'll bet you like the 80Hz setting better - you actually have more usable power going to the speaker, since the subwoofer does the low-end work which can really rob power from a receiver.

If this actually sounds better, assume you'll need a power amplifier to add to your setup. It doesn't need to be hugely expensive, but you'll want to get one that has 120 to 200 watts per channel, so you have plenty of reserve.

Side note: My wife insisted on the finest cabinetry for speakers we could get, and we very quickly settled on Monitor Audio. They have the best craftsmanship for cabinet work I've seen, until you triple the price. Had I known about the power issue, I'd have gotten an amplifier, and the MA's.

[DavePS3]

Using your ears is actually best. You need to find where you'r mains cut off and although the specs may say 'down to 20hz' (example)... it's rarely true. If your mains have a cut off at 30hz for example, best to set your sub just above that. Say, 35 to 30. Basically, the sub will need to fill in where the mains stop. The sub will give you what it is built to do, whether it's down to 20 or 18hz, no matter where you set it but the more mid-range bass, is where you'll need to listen for... car doors slamming... gunshots... if you want more impact on those frequencies, adjust higher on the sub. If those frequencies are too overbearing, it usually means your mains are covering it well enough and you can set your sub lower to let those mains do what they're built to do.

[BlueThunder]

Have just added some pics of my set-up here if it helps any.

https://forum.blu-ray.com/showpost.p...postcount=1316

thanks for the help so far, and it will give me something to experiment with.

[musicman1999]

Your front speakers have a sensitivity of 91db which makes them easy to drive, your receiver should have no problem. Does your receiver allow the crossover to be set separately for front, center and rear? If so , use this, it will allow the crossover for the front to be set lower than for the rear and makes the sub easier to integrate with the speakers. My fronts are 45hz, center 55hz rears 65hz. Works well for me.

bill

[BlueThunder]

Thanks al for your comments.

Blu-Dog, as far as I know the LX70 in Europe is the same as the Elite in the US. The LX70 I have is rated at 180W at 6R or 150 at 8R so there should be plenty of power in the amplifier.

It is possible to adjust each channel level seperatly and also to adjust the EQ for each channel. I notice the the low frequency for the fronts was suppressed with the Auto calabration so I boosted this again. I also supressed the rear low frequecy a bit as there are not as big as the fronts.

I also notice that at high volume the sound is very bright. Will this brightness dampen as the speakers break in?

I will continue to experiment and let you know. Thanks

[WickyWoo]

Have just added some pics of my set-up here if it helps any

you need a bigger TV man

[BlueThunder]

Originally Posted by WickyWoo

you need a bigger TV man

I think I need a salary rise

Hopefully in the next month or so though. looking at the new Sony 46" X3500 (Europe). Just need to check if I can strech to 52"

[Clark Kent]

Check out Stereophile's measurements of the RS6s:

http://www.stereophile.com/floorloud...or/index3.html

They loved them by the way for the price class. What you're looking for is where do the speakers begin to roll off their frequency response which is the best point to use for the crossover. Nominally their frequency response is listed as 38Hz–30kHz. Going by figure 3 of the above link I would say 60Hz would make a good crossover point but it might vary from room to room. In some rooms it will be 80Hz.

[jdc115]

Originally Posted by BlueThunder

Have just added some pics of my set-up here if it helps any.

https://forum.blu-ray.com/showpost.p...postcount=1316

thanks for the help so far, and it will give me something to experiment with.

Nice room, you should clean up the wiring so you don't see them hanging down the walls. But you probably are still in progress

[Durentis]

Originally Posted by BlueThunder

looking at the new Sony 46" X3500 (Europe). Just need to check if I can strech to 52"

With that nice front wall, you should be looking at DLP projectors, not HDTVs.. I'll never be able to go back to a TV.

[musicman1999]

Before you get to far into crossovers you need to have a look at speaker placement.The fronts should be out into the room a couple of feet to get them away from the walls, also
they should be aligned towards the main sating position.Having them against the wall and one near a corner will cause a bass reinforcement and will alter bass response negatively.

bill

[Blu-Dog]

Originally Posted by BlueThunder

Have just added some pics of my set-up here if it helps any.

https://forum.blu-ray.com/showpost.p...postcount=1316

thanks for the help so far, and it will give me something to experiment with.

Man, those are beautiful speakers.

I wound up with Definitive Technology Supertowers and their smaller cousins for the family room, and Sonus Faber Domus units in the living room - all stunners for looks, and sound - but I think I'll get the Monitor Audio kit like yours for my youngest son. I just like the way they look, and now that I've found out how they sound...

i gotta quit drooling its undignified

[Blu-Dog]

Originally Posted by musicman1999

Your front speakers have a sensitivity of 91db which makes them easy to drive, your receiver should have no problem. Does your receiver allow the crossover to be set separately for front, center and rear? If so , use this, it will allow the crossover for the front to be set lower than for the rear and makes the sub easier to integrate with the speakers. My fronts are 45hz, center 55hz rears 65hz. Works well for me.

bill

I am skeptical of that db rating...the speaker as a unit may be 91db, but not each element in it. The tweeters BLAST in the Monitor units, but the woofers don't - you have to really feed those guys. So you really wind up with two widely divergent rolloff curves unless you have a lot of power behind them.

[musicman1999]

That is according to their web page, the speakers have internal crossovers, there can be only one sensitivity rating for a speaker, and 91db will make it easy to drive.

bill

[Blu-Dog]

Originally Posted by BlueThunder

Thanks al for your comments.

Blu-Dog, as far as I know the LX70 in Europe is the same as the Elite in the US. The LX70 I have is rated at 180W at 6R or 150 at 8R so there should be plenty of power in the amplifier.

It is possible to adjust each channel level seperatly and also to adjust the EQ for each channel. I notice the the low frequency for the fronts was suppressed with the Auto calabration so I boosted this again. I also supressed the rear low frequecy a bit as there are not as big as the fronts.

I also notice that at high volume the sound is very bright. Will this brightness dampen as the speakers break in?

I will continue to experiment and let you know. Thanks

The sound will stay very bright, as the MA's have a really strong tweeter in them - and the woofers are stiff metalized cones. This will always result in a bright sound. You may want to fiddle with the equalizer in your receiver a bit to modify it if it becomes annoying.

Brightness is great for movies (many of which are recorded with muddled sound), maybe not so great for some music. Brightness is great for live concert recordings, less so for jazz - your mileage may vary.

You're on the right track for sound adjustments. Keep fooling around with it. That receiver is plenty powerful, but if you run at high volume for a while, check and see how much heat you're building up.

One other thing - my Elites have a setting for 6 ohm speakers. I advise not using that setting, it just drops the rail voltage for the transformer, and was probably put in there by Pioneer's legal department. Just make sure your receiver isn't getting too hot.

You probably won't wind up cranking it that hard, and another poster mentioned the speaker overall has 91db efficiency.

[Blu-Dog]

Originally Posted by musicman1999

That is according to their web page, the speakers have internal crossovers, there can be only one sensitivity rating for a speaker, and 91db will make it easy to drive.

bill

Agreed; and I've actually auditioned these units. The point of the efficiency rating is that the 91db rating is at the classic 1 watt level. Once you start adding power, the db efficiency curve will change.

My understanding (correct me if I'm wrong) is that the output power of the amplifier does not mean all of the power is actually being used by the receiver. Perhaps 10-15 watts of power is actually used by a given speaker, with much higher power being sent to it from the receiver.

This curve is different for every speaker, based on the crossover type and frequency cutoffs, and the elements in the speaker. So for the rating of 91db, the MA's are fed one watt of power. The efficiency curve may not be the same at 5 watts, or 10 watts, so I've always been careful about using the db rating as a comparison between speakers.

The other question (perhaps not an issue here, this chap has a brute force receiver) is how much reserve power an amplifier can provide. Some are rated for high output - but can't sustain high power levels for long, usually causing distortion or clipping. This is especially common when pushing large drivers with lots of bass tones.

I hear what you're saying about the db rating, but I just wonder sometimes how accurate the manufacturer's rating is when looked at on a curve.

[musicman1999]

What the sensitivity rating means is how loud a speaker will be when given a certain amount of power, as you say 1 watt.So this speaker when fed 1 watt, measured 1 meter from the speaker will output 91db.To add 3db you typically need to double amp power, so 2 watts=94db, 4 watts=97db etc.No matter how you look at it, any moderate power amp will drive these very well.

bill

[Clark Kent]

If anyone had checked the link I gave above this is what they say about the speakers measured sensitivity:

"The Monitor Audio Silver RS6's estimated voltage sensitivity was 89.5dB(B)/2.83V/m, which, if slightly below the specified 91dB, is still higher than average. Its impedance (fig.1) remains above 6 ohms for almost the entire audioband, with a minimum value of 4.5 ohms at 165Hz. As well as being usefully sensitive, the RS6 is also an easy load for the amplifier to drive: textbook requirements for a speaker that will be used with inexpensive amplification."