Axiom Home Page Forums General Discussion Home Theater question about speakers

Hey there I'm starting to put together my home theater and I have a question about which speakers I should look into. I've already decided on your line of products so now I just have a choice of which ones to get.

I'll be running everything through a denon 3802 and be using it for 60/40 movies/music. I plan on picking up the M60's as mains and the 150 for a center channel. I also plan on picking up a sub from another company in the future but not before i finish purchasing the axioms. A major question I have is what should I get for rear channels? a couple m22 bookshelves or maybe the Q series of speakers. I'm a bit confused on the bipolar/dipolar issue. Originally I had figured I'd get a couple bookshelves for the rear right/left and then maybe a center rear. Is that do-able? The floor is tiled, no carpet, measurements 23.5 by 13 or so.

Any suggestion would be helpful.

Hello bhunt

IMO - You have picked out the basics of a real good system - and I believe there are quite a few posters on this forum that would agree with me. The Denon Reciever will be MORE than adequate for the 60s and 150. As far as surrounds go, I suggest you dig thru some recent posts by Alan, cheeseroo, and others regarding the multipolar radiating designs of the QS speakers vs the direct sounds of the M series bookshelves. I think you will be able to gleen some really helpful info from them. chesseroo recently posted a pretty fine review of the QS8 vs M22s in his system (with the same front speakers as you want to get) - I don't know - perhaps you read it and now want other opnions on them as well.

I believe that for most home theater setups with normal sized living room/den layouts, the quad-polar design will give you more flexability for where you can place the speakers without causing undue localization issues and will provide a more enjoyable 360 degree sound experience. Just keep them out of the corners of the room.

Good luck!

Randyman

my simple reply is get QS8's for the back if you can fit them properly. Place them not directly behind you, but a tad to the sides (if you know what i mean).

I got a somewhat similar setup last week - Denon 3802 with M60s for the front, VP 150 for the center and QS8s for the surrounds along with a EP175 (I toyed with the idea of a Hsu VTF for a while, but eventualy decided to go with an Axiom for its musicality); My room is similarly sized - 25 feet X 14 feet with a vaulted ceiling but with carpet. The system sounds nice but does not produce as much output as I thought it would (based on a lot of posts in these forums), especially when watching DVD movies. The output with music CD's is appreciably higher. I suppose I should have gone for the larger sub. The QS8s are good but a couple of times when listening to music, I have been rattled by some resonance - kind of a buzzing noise that is not part of the recording but is being generated by the speakers. However, the sound from the other speakers (I tried running 5 channel stereo and tested repeatedly) was clean. I am not sure if this is present only in the two QS8s that I got (FO) or is a general issue with the 8s. I would suggest that you try them out and if not happy, get a pair of bookshelves instead.

PS: I got a pair of the QSS8 stands to get around problems with speaker placement. The stands (not made of real hard wood incidentally) look rather tacky with a thin coating of vinyl (note to Axiom: A pair of elegant but strong Aluminum stands would considerably enhance the QS8s). If you are planning to get stands, try to get one of the alloy stands that can accommodate the QS8s.

Prem, if you are not satisfied with the speakers or the stands, return them.
Pay another 5 grand for larger louder machines if volume is
your main concern. But if your couch is actually 20+ feet away from your main speakers, then the volume issue is obvious.
Keep in mind that pushing your volume to really high levels will eventually result in distortion which can send any of your speakers buzzing.To suggest that the buzzing is a "general issue with the S8s" is a bit of a premature generalization don't you think?

Well Chesseroo, Let us see; The Denon 3802 has an maximum output of between ~110W at 8 Ohms and ~130W at 6 Ohms depending on speaker impedance. Incidentally, I was running the speakers at well below full power. The QS8s are rated at 400W (rms presumably). The specs on the website says that their impedance is 6 Ohms and the spec sheet that came with the speakers listed it (if I recall correctly) as 4 Ohms. I am aware that speaker impedance is a function of the frequency, so let us say that the impedance varies between 4 Ohms to 6 Ohms over a 100-20KHz band. I am no expert on speaker loading but that is enough to convince me that it is not a power issue (but please feel free to correct me if need be).

The buzzing noise that I referred to came only from the QS8s and as I said in my earlier post, the other three speakers reproduced the music cleanly (I was playing 5 channel stereo). The noise also was present simultaneously in both the QS8s; Further this was the case only with a particular CD and that too only at times when the male vocalist was hitting particular notes. The noise was incremental to the otherwise decent performance of the 8s. To me that is not reason enough to simply return the speakers as you seem to suggest. There may be a simple reason for it as also a easy remedy. It may be something with my setup. The purpose of my post was to seek feedback from others in case they have experienced the same. The comment about "in general" is for the designer who may have made that design compromise (due to say, size considerations) while designing the speaker believing that such a situation (of that particular resonance) is infrequent enough to not warrant spending an inordinate amount of resources to rectify it, and if so, inform the crowd. Also as I said both the 8's exhibited the artefact.

Lastly, regarding the output, my concern was more regarding the difference between DVD soundtracks and music CDs (by the way I play both on the same DVD player). You will note that I had already ascribed in my previous post, in a general sense, part of the blame for the perceived level of output on the choice of the sub. Further since the speakers have considerable reserve in power handling, getting a pre-amp or a higher powered receiver is one solution. My post was meant to get readers' ideas on other possibilities.

As i begin to reply to your post i'm not really sure where to start. Your first paragraph mentions power output, but i never contended you were having a power issue. Distortion comes from your receiver/amp when pushed to its upper limits. For example, someone has a party and puts their receiver up to the 95%+ volume level to get max sound and instead gets increasing distortion.
This type of effect occurs with many pieces of technology as their upper limits are approached. Efficiency decreases and detrimental effects increase. You could toss in cars and RPM to HP data, planes and speed vs. shear, etc. Home electronics are no different be it computers or receivers.
Hence, what i was implying was that if you were turning up your volume dial to get more volume from your system, you may be reaching that upper limit. What i mean by 'upper' is really quite high as in 95% or more of max give or take a couple of percentage points. Now i don't know what level of volume you were using for listening but it was a suggestion.
I personally own an Onkyo 797 which is very comparable in specs to your Denon 3802 (a nice receiver choice) and neither of us have paid $10,000 for a receiver that may be alot cleaner at higher volumes. Higher quality parts, better engineering is simply beyond us (at least at the present time it appears).

After looking at your room specs, i was also wondering how far away your listening spot was compared to your speakers. Most listeners may sit around 6 to 15 feet away but beyond that, i would imagine the tv would start getting harder to see (not to mention the LCD numbers on your audio equipment). The further away your listening spot, the less volume you should expect of course. Hence, people in the forums who say the speakers put out plenty of sound may be sitting 8 feet away while your own listening position could be double that distance. This is information you never provided in the original post.

I am also confused as to what you are referring to as 'level of output' and 'choice of sub'.
Do you mean to say the volume of your entire system is fine and just the sub-sound volumes are too low?

In regards to the volume differences between dvds and cds, again, what is your source?
DVD players typically list specifications, on S/N ratios, dynamic range, frequency response and sensitivity, separately for dvd and cds. How these values are different within the same player has to do with the DAC and DVD video D/A decoders being separate entities. I'm not surprised at all that you may encounter volume differences between the cd and dvd.

As for the buzzing, it is possible that you have drivers that need replacing but there are several steps you should undertake to remove the playing source as the problem first before deciding this is a design flaw and not something in your setup as you mentioned.
Your suggestion that the company is hiding a flaw that they know about may be a little harsh:

"The comment about "in general" is for the designer who may have made that design compromise...while designing the speaker believing that such a situation...is infrequent enough to not warrant spending an inordinate amount of resources to rectify it"

Ian can of course defend himself and his own company here but i don't believe he would feel he has to. The QS8s are some of the best designed surround speakers that i've heard in my lifetime. That may or may not say alot i suppose.

However, all that aside, I would be glad to try out a test with your song list (which includes the tune that seems to elicit this buzzing sound in your QS8s) with my own setup. Then i can crank up the volume with the same song and speakers but with different source equipment to check for this buzzing noise.
If the buzz is particular to your individual QS8s or source equipment then i won't hear it.
If the buzz is due to a QS8 design flaw then it should be reproduced on my system as well. However the song itself may also be the cause of this problem if it was recorded to actually make such a noise. Very recently some string cello twangs had my thinking there was something wrong with my tweeters in the M60s but it was actually the accurate reproduction of the song that had me fooled.

I am presently using, as previously mentioned, an Onkyo DS797 receiver with a Panasonic CV52 dvd player. I have M60s as mains, the VP150, EP350 and QS8s for surrounds.Please pass along your song info and i can get started.

Let me fill in the gaps first:

This is the setup I have-

Denon 3802 receiver
Toshiba 36" flat HDTV monitor
Daewoo DVD player
Toshiba VCR
Sharp VCR
M60s on the front (set about 4' on either side of the TV)
VP 150 on top of the TV
EP175 sub between the TV and the left front speaker
QS8s on either side of the couch set 1' back perhaps
12AWG stranded copper wire for all speakers
RCA gold interconnects for the components as well as the sub

My listening position is around 10-12 feet away from the TV depending on which corner of the couch I am measuring from

The room itself is carpeted and is around 25'L X 14'W X 25'H with the living room opening into the foyer above 12' or so.

Now to your other questions:

What I am referring to when I unscientifically equate 'level of output' and 'choice of sub' is this: I recall having read in some posts that an inadequate sub (given the size of the room) can give rise to a perception of overall lack of power. I have been wondering if a larger sub (say the EP 350) would more adequately complement the output from the other speakers and thereby provide a more balanced listening experience. Admittedly this is subjective and very much a function of the room's acoustic profile. Better positioning of the sub and/or phase control may be a temporary solution till I can come up with another $1000 or so for another sub (note to axiom: it may be a good idea to provide a continuously variable phase shift control on the subs).

By the way, the spec sheet that came with the sub advised listeners not turn up the output of the sub beyond the halfway mark - maybe this is a way of creating some dynamic headroom while still protecting the driver, but if some reader could come up with a better explanation for this, please inform.

As I said earlier, I perceive low output levels only when I am playing DVDs; the CDs sound quite loud (without changing the volume on the receiver). I am planning to get a second DVD player soon. I will test this again on the new source and report if I find any differences.

I do not believe I suggested anywhere that the company is hiding a design flaw. Apologise if anybody got that impression from my posts. Needless to say, good design is all about making the right compromises, which by definition give rise to some shortcomings in reference to the targeted price/performance point. To take one of you own examples, if a gasoline engine designer is targeting low-end torque, the best way to get there is through larger displacement, which obviously sacrifices fuel economy. There may be designs that overcome this tradeoff but these are likely to be more complicated and expensive, or require exotic fuels. likewise, when designing the enclosure of the QS8s or the fasteners, the designer may have been limited by cost and size considerations in eliminating all possible resonances. In my opinion, as long as the artefact has a minimal probability of occurence, and does not interfere in most normal circumstances, it is not a flaw but an acceptable shortcoming. If indeed there is such a design consideration, I am merely seeking more information so I can try and manage around it. For my next purchase (the surround backs), I can accordingly settle on the M3s instead of the QS8s if the designer regards M3s to be better in this particular circumstance. Lastly, if the problem I have described above has not been experienced by the designer during product testing, then it can only benefit him/her to be aware of the issue and design around it if reasonably possible when the next design update is due.

I do not disagree that QS8s sound great as sorround speakers go and I am sure I would not buy anything else for a sorround speaker; maybe for the backs but not for the main sorrounds.

The ZZ.. ZZZ.... noise (it seemed as if it originated from cabinet resonance) was present when I was playing an Indian film music CD. The name of the movie is 'Sagara Sangamam'. I am not sure you would be able to get the CD easily, but I would be happy to make a copy of the CD if you like and are still interested in testing it out.

Well now i have a clear picture of your setup Prem. You have some nice components there.
I understand you level of output statement now as well and i would have to say the 'output' that is dependant on the subwoofer is as you say, a very personal choice. I'm not a big sub-sonic noise fan but i do like a rumble with truly big explosions and the low hum of a pipe organ. I chose the EP350 just because i could afford it but i was realistically looking at the EP175 originally. I would hazard a guess that you enjoy the larger bass 'volume' per se and hence may again, as you mention, prefer to actually have a larger subwoofer (or more than one) to give you that effect you desire.

I have yet to turn the sub volume knob on the EP350 above the 25% mark. Any louder and, as i said earlier, it will blow out my basement window. Perhaps the spec sheet was more of a warning for ear drum protection. Who knows.

Your testing of dvd vs another dvd or cd player is exactly what i've been doing with 4 units over the past 2 weeks until i finally settled on one dvd player. I think i've posted some of my thoughts somewhere recently on this but would love to hear your results as well.

As for the design flaw, ask Ian or Alan about that subject. Ian will be able to tell you best the answer you seek regarding frequency issues with the QS8s since he designs them. I have a feeling he does rather extensive testing on his speakers across all ranges but bring this up with him. I'm sure he will be glad to answer your queries. It's not often you get to converse directly with the speaker designer/owner of a company.

In regard to your music tested, it is definitely something that i may have a hard time finding locally. You can always try the sound on a different set of speakers as well to again remove the source as the potential problem. There is the possibility that the sound from the surrounds is due to the playback of that music in the surround setting. I would be mildly surprised if the music truly just hit some notes that the speakers could not handle.
Does this occur with any other music or movies at all? Or just that one single piece?
Most of my testing music was selected for quality recordings, presence of clear vocals, presence of clear mid range sounds, single and mutliple instruments, low bass and sub-sonic bass as well as screaming treble. I've done my best to stress the speaker ranges during my in house testing before i settled on the Axioms. I can't say that anything in the upper ranges bothered my QS8s.
There are actual sound range test cds that you can buy however. This may be another option in narrowing down that range of sound you think the QS8s seem to fail upon playing.

While this discussion is going on, taking a cue from your earlier post, I took a quick peek this afternoon to check if all the drivers in the QS8s are in good order. I was surprised to find that one of the tweeters on my left speaker had no sound. The left tweeter in the VP150 also was not sounding right. I have called Joe and left him a message on this (Does Canada observe a holiday on July 04 too?) and will wait for his call back to ascertain the tweeters' condition. Since they are brand new (two weeks old), I am guessing that it could not be anything worse than a bad connection inside.

Incidentally, When I received my shipment, the VP150 and QS8s were not double boxed whereas the M60s and the sub were. I guess there is a value threshold involved! As a matter of fact the styrofoam inserts in the QS8 box were in several pieces when I opened. However, I found no apparent damage and did not think twice about it. I would not be surprised if some connection internally was dislodged during its journey; We will see.

Can a bad tweeter result in the other tweeter being overloaded? Should I disconnect the speaker till the problem is fixed?

Any informed advice would serve to greatly reduce my angst!