I have Monitor Audio Silver S10 fronts and a SLCR center. I couldn't decide between the QS8 or the MA SFX surrounds so I picked up a a pair of the QS8 and SFX to compare against each other. The SFX goes down to 60hz +/-3db, so setting the crossover is easy, but the QS8 only goes down to 90hz+/-3db and then trails off -9 dbs(which is a lot) down to 65hz.
Since the QS8 has usuable sound at the +/-3 db at 90hz how do you integrate a 80hz or lower crosover without having a whole in your frequency range?
Thanks
Legairre
Ola Legairre
I use the Outlaw ICBM and set the x-over at 100 Hz for the QS8s.
I also cross over VP100 and QS8 at 100, 80 or 60 for the mains.
Some people cross over at 80 and say the hole doesn't make much difference... and they are probably right.
John,
What component do you use that allows for the multiple crossovers? Is the function in your receiver?
And 2x6,
Is the outlaw only for dvd-a and sacd? Or can it be used in DTS, DolbyPL2 and other 5.1?
2x6spds,
Thanks for the reply. Here's how I currently run my old surrounds. I have one sub directly under each surround speakers.
1.) In my pre amp I set the surrounds to "Large" so the surrounds get a full range signal. This is just like setting the fronts to large(no LFE signal).
2.) Then I use the "high pass filter" on my surround subs by using the speaker level connections(not line level). You simply run the Left pos/neg speaker wire from the pre amp to the speaker level "in" on the sub and then you run another speaker wire from the sub speaker level "out" up to the surround pos/neg and repeat the same process with right surround and sub.
3.) Then set the subs "high pass" crossosver to say 75hz(that's where my current surrounds roll off).
4.) Since the sub is getting a full range signal it's "high pass" crossover sends everything below the crossover to the sub and anything above the crossover the the surround.
This allow me to run my fronts and center crossed at 60hz and my surrounds at 70hz
It's really just a poor mans ICBM. I was hoping to not have to use the subs anymore by getting some good surrounds that went down to around 60hz , but if I keep the QS8 it looks like that won't be possible.
OK so 2x6spds uses an ICBM, how do the rest of you QS8 guys handle the 90hz limitation of the QS8? Come on I know you guys are out there and lots of you have QS8 surrounds.
2x6,
I just checked Outlaw's site ans it is only for sacd/dvd-a.
Flexible bass management is the Harman Kardon "secret sauce". The HK bass management allows mains, center, surrounds, and rears (on a 7.1) each to have a different crossover frequency. In my case I'm running a 630 but all the HK receivers (at least down/back to the 130) have this ability.
There are a couple of weaknesses in the HK bass management as well, but nothing serious :
1. There is no way to route low notes from center and surrounds to your mains if you are running "Large" mains without a sub.
2. LFE channel is low pass filtered and the LPF frequency has to be the same as one of your crossover frequencies for main, center, surrounds or rears. Not a big deal as long as you cross *something* over at 100.
I imagine any of the outboard bass management units have a similar capability, but HK is the only mfg I know of who builds it into a receiver. Could be wrong there though...
Thanks John,
I knew I liked H/K!
I suppose I could run my 60's at Large and set my X-over at 100 hz.
Can one of you please explain why there are two freq response ratings?
eg Freq Resp +/-3db (Hz ) 95 - 22kHz
Freq Resp +3dB- 9dB (Hz) 65 - 22kHz
If you use the Outlaw ICBM between the amps and processor you can control the x-over points whatever the source.
2x6,
Amps and processor (separates right?).... does that mean it can't be done with a receiver?
Good post Legairre,
I don't really notice a hole BUT part of the enjoyment of HT is the tweaking.
You're Idea with the subs is kinda neat, but I guess it forces the placement of your surround subs.
Did it work well? also does that mean you have 3 subs?
As I recall, the only way to control the x-overs with the Outlaw ICBM for all sources is if you use separates.
Another plus for the ICBM is that it has stereo sub pre-outs.
bridgeman can you please elaborate about what you were saying with the hk's why would "something" have to be crossed over at 100hz? im not to knowledgeable about the difference between low pass filter and high pass filter
Wow! lots of good info in here now. I posted right after 2x6spds and i didn't know al you guys had joined in so
thank you to everyone for contributing. This method was described in a magazine article that had 7 pages of movies with surround bass down to 50hz in the surrounds. It's really just a way of simutating a full range speakers in the rear.
In reply to:
You're Idea with the subs is kinda neat, but I guess it forces the placement of your surround subs.
Did it work well? also does that mean you have 3 subs?
You really do want the subs under the surrounds since they play the bass part of the full range signal below the high pass crossover and the surrounds play the frequencies above the crossover. It's like having full range speakers in the rear, but without a big speaker taking up space and standing tall.
I have four subs two 250w 12" subs for the low pass LFE with one in each front corner and the two high pass 150w 10" surround subs. It sounds like a lot of subs, but the surround ones are just helping simulate full range speakers in the rear while the two front play all the LFE. This setup allows a lot of flexibility, because my center is rated to 45hz and my fronts to 32hz so a 60hz crossover for the fronts and center works great while a 75hz high pass crossover works great in the surrounds. The surround subs catch any surround bass(not LFE) below 75hz while the surround speakers handle everything above the high pass crossover.
Yes!! Thank-you everyone for responding.
In between reading and posts I checked out this link. Good introductory to bass management and how important it could be with sacd/dvd-a
good tutorial on bass management
Legairre,
Sounds (reads) like a really nice set-up!
kk, i read that tutorial but i still dont understand what bridgman was talking about with the hk's as far as low pass filter and LFE
Ooo..so now I need one of those. What's the WAF on another $250.
The just of it, I think is that H/K will allow for multiple crossovers whereas my denon won't.
If all your speakers frequecy ranges, are not the same, one crossover (say 80 hz) may leave a hole in your listening environment.
I think that's what your asking...
Hope this helps.
Crossover: A component that divides an audio signal into two or more ranges by frequency, sending, for example, low frequencies to one output and high frequencies to another. An active crossover is powered and divides the line-level audio signal prior to amplification. A passive crossover uses no external power supply and may be used either at line level or, more commonly, at speaker level to divide the signal after amplification and send the low frequencies to the woofer and the high frequencies to the tweeter.
Crossover Frequency: The frequency at which an audio signal is divided. 80 Hz is a typical subwoofer crossover point and is the recommended crossover point in theatrical and home THX systems. Frequencies below 80 Hz are sent to the subwoofer; signals above 80 Hz are sent to the main speakers
Frequency Response: A measure of what frequencies can be reproduced and how accurately they are reproduced. A measurement of 20 to 20,000 Hz ± 3dB means those frequencies between 20 and 20,000 Hz can be reproduced no more than 3 dB above or below a reference frequency level.
LFE: Low Frequency Effects track. The .1 channel of a Dolby Digital, DTS, or SDDS soundtrack. The LFE is strictly low-frequency information (20 to 120 Hz, with 115 dB of dynamic range) that's added to the soundtrack for extra effect. This track does not inherently contain all the bass of the soundtrack.
Low Pass: A filter that lets low frequencies go through but doesn't let high frequencies go through. Same as high cut
High Pass: A filter that passes high frequencies, and attenuates low frequencies. Same as low cut.
gloosary
Something for BrenR
p.s. because BrenR has some of the most in depth responses on these boards.
ok, thnx, i understand for the most part but im still wondering... when i get my 60's 150 and qs8's i plan to set the 150 and the qs8's to 90hertz (only level my receiver allows) and leave the 60's on "large" (my present yamaha allows for large mains as well as a sub) so that way theoretically my main will get the full range. however when i switch to an hk in the future (probably 435) im wondering if i can still do it this way, or do i have to cross one over at 100hz as bridgman said
In reply to:
Can one of you please explain why there are two freq response ratings?
Freq Resp +/-3db (Hz ) 95 - 22kHz
Freq Resp +3dB- 9dB (Hz) 65 - 22kHz
The only numbers that really count are the first ones(+/-3db 95Hz - 22kHz) because at those frequencies the speaker could be either up or down 3db @ 95dB. The second set is a companies way of say "look our speakers trail off but will produce sound at a certain frequency". The QS8 will be down -9db when you get to 65hz. Sure the QS8 will produce sound at 65hz, but if you look at all other numbers:
+/-3db 95Hz - 22kHz
+3dB/-9dB 65Hz - 22kHz
SPL in Room 1w/1m(dB): 95 dB
This should mean that the QS8 can produce a frequency response of 95Hz-22kHz @ 95dB and will produce sound in the 65Hz-22kHz, but the SPL will automatically lower by -9dB at 65Hz(86dB). The only numbers that count are the ones that show the highest SPL over a freq range. The other numbers are just marketing.
The QS8 do sound fantastic, but the freq respone is pretty poor. I haven't performed the comparison with the MA SFX yet, but I think even with the poor freq response of the QS8 the SFX has a lot of competition. With proper bass management the QS8 is a killer. If you use an HK, ICBM, sub setup like mine or can set your crossover 80hz or higher it's a real winner.
In my setup the QS8 is the absolute best sounding surround I've ever heard. Now I just need to setup the SFX and see how they sound.
Any of you folks have a couple of links to where these audio terms are defined as "standards?"
Also looking for a couple of "good" links to articles on how you are supposed to set your crossovers. I've got a hunch that it really doesn't matter that much because if you use the default receiver settings (flat response), the speakers take care of it for you, but I would like to prove myself wrong.
The beauty of the Outlaw ICBM between the processor and amps is that it will work even if you are playing DVD Audio or SACD which normally bypass all of your receiver's internal cross-over settings. With the ICBM you can set the x-over point for your Front (LR), Center, Surround (LR) and Back (mono) channels and you get stereo preouts for 2 subs.
If you have a really big room, then putting a sub under each speaker would approximate full range speakers in each position. But, since low frequencies are much less directional than higher frequencies, you really don't need a sub under each speaker. A properly placed sub will contribute to the 'wall of sound' effect and appear to be coming from the speakers, or if you really hit the sweet spot, it will sound like it's everywhere.
thanks again Legairre,
And I have to agree The QS-8's are great sounding speakers.
>>kk, i read that tutorial but i still dont understand what bridgman was talking about with the hk's as far as low pass filter and LFE
I don't blame you, I barely understand it myself
In a 5.1 system, the .1 channel is also called the LFE (Low Frequency Effects) channel. In a Dolby Digital soundtrack the "rules" for LFE are pretty specific (eg no content over 120 Hz) so you can just route the LFE channel (the .1) to your subwoofer without any worries.
In DTS and other standards, apparently, there is more variation from one recording to the next. I have read of a couple of cases where the .1 channel is actually full range (low and high frequencies) just like the other 5 channels. I guess that is why the LFE channel is usually run through a low pass filter (only letting the bass through) before going to the sub but I don't know for sure.
BTW, when we talk about "bass management" what we're referring to is the crossovers and mixers in the receiver which do things like :
- take signals from mains/surrounds/center and split them into low & high frequencies (if that speaker is set to "small")
- combine the low frequencies from "small" speakers (the 5) with the LFE channel (the .1) and send the result to the subwoofer
- sometimes allow low frequences frim "small" center and surrounds to be routed to "large" mains (eg. if you don't have a sub)
Bass management is built into all AV receivers and is also available in outboard units like the Outlaw box.
In reply to:
As I recall, the only way to control the x-overs with the Outlaw ICBM for all sources is if you use separates.
Sorry if I'm late on this one guys, but I just wanted to clarify this statement. You can also use the Outlaw ICBM for all sources if your receiver has pre-outs and main-ins. My NAD T762 has this and that's where I use my ICBM and it works great. Anyway, glad to hear you're enjoying the QS8's.
Hey guys, have any of you tried a third QS8 as a center back? I noticed Axiom sells them either as a pair or as a single speaker. I'm asking because I currently run 7.1 with two center back speakers 4ft apart and because of the 180 degree patern of the QS8 I don't think two would be necessary as center back speakers in a 13x24 room. I currently have direct radiators as my two center backs , but how would a single QS8 work as a center back?
Thanks
Legairre
I have a 5.2 system in my office, haven't set up the big HT system yet, but I ran a 7.2 system in my last place. When I set up the big system again, I think I'll leave it at 5.2. In any case, I don't think there is any 7.1 software, (movies or music) anyway, I don't think the back surrounds add much if your side surrounds are well placed. Bottom line, IMnsHO, if you want to go with a back surround, go with a single center, since the back channels are mono anyway.
Thanks 2x6spds,
Very few movies have descrete back center channel information. Most of the center back info is like you said "mono", but there are good bit of DTS-ES descrete 6.1 movies. Having two center back speakers is recommended for coverage not information, because 7.1 descrete movies don't exist in home theater yet.
I wasn't so much concerned about the mono vs. descrete issue, because I have dual direct radiating center backs now for coverage. What I was trying to find out is, if a QS8 would work well as a back channel speaker. The QS8 has a 180 degree dispersion and would cover a wide area so would one work instead of two. It's been recommended to only use direct radiators as center backs the same way it's recommended that direct radiators be used for side surrounds for DVD-A and SACD. Since the QS8 is a quadrapole design and not a dipole or bipole they seem to work well with DVD-A and SACD. I was wondering if they would also work as a center back and has anyone tried this.
Thanks
Legairre
In reply to:
What I was trying to find out is, if a QS8 would work well as a back channel speaker. The QS8 has a 180 degree dispersion and would cover a wide area so would one work instead of two.
My Rear Centre is a QS4 (same as my surrounds) and it does very well. I have tried an M22 back there (tested out a bunch of different M3/M22 configurations this spring when I had the opportunity) and it was -- odd. I could go into a bunch of adjectives here, but I think that covers it, even when calibrated, there was wrap-around audio around me from the surrounds and
HEY, LISTEN IT'S RAINING BACK HERE from the M22. Too bad, really - a direct radiator would have been cheaper. Standard disclaimers apply - I prefer the enveloping sound of diffuse surrounds, my listening position does not have much room behind it, since it was a speaker I knew I had just installed, my brain was actively listening to it, your mileage may vary, etc...
Bren R.
My previous 7.2 system used 2x M2s in the back surround position (FMB aimed down a few degrees) 2xQS8s in the side surround positions, and a pair of M60 like Michaura M665s up front (2 subs, SVS 20-39 and a Velodyne CHT10), heavily modded Merak center (2x6.5" axiom drivers and a horn). It all sounded pretty good, but the M2s in the back position were a step down in sound quality (HT) from the pair of Mission 77ds speakers I used before - it could be the M2s didn't like the high position as much as the Missions, dunno.
Great thread. Very informative.
ok, thnx bridman, i think i finally understand, i guess ill start fooling around one i get my full system...i dont even have a spl meter yet...
That's the only way to really learn. Fool around with the settings for a while... when you're good and confused ask some questions here... then fool around with the settings some more and repeat for a while.
That's how I learned. I imagine that's how most of us learned...
Legairre, on your opening question, although a 90Hz crossover might be more nearly ideal for QS8s, since the crossover isn't a sharp cutoff no "hole" is really created with the 80Hz setting and several owners use it with satisfaction.
As to using a single QS8 for a back surround, note that although there's no such thing as a 7.1 format(at most there's matrixed or discrete 6th channel material from DD and DTS), Dolby, THX, etc. recommend that the mono 6th channel material be reproduced with two separated rear speakers. The primary reason is a psychoacoustic reversal effect in which a sound coming from one speaker directly behind a listener will instead appear to come from directly in front of him. It's been suggested that with a speaker such as the QS which has a very wide dispersion this effect is less likely to occur. A second possible basis for using two rear surrounds is that when 2-6 channel material is processed with DPLIIx, Logic 7, etc. into seven speaker material the 6th and 7th speakers often receive different information and they should be separated widely enough so that listeners get both a left rear and right rear effect.
Thanks John,
I assume the hole is less likely to occur due to the QS8 trailing of to -9dB@65Hz. As for using the QS8 as a center back, I've always used two center back speakers to counter the psychoacoustic effect. I've tried it with one and it's always seemed like the sounds where coming from the front center channel just as you described.
You and BrenR both answered the one or two QS8 question. I assumed that due to the dispertion of the QS8 only one center back would be necessary, but like you said DPLIIx can seperate the 6th and 7th channel. My room works really well with two direct radiating back speakers, but I think two QS8 may be a bit much in a room thats 13' wide.