Axiom Home Page Forums General Discussion Home Theater Ian - Benefits of floor standing models

Ian:

I'm interested in checking out a set of Axioms for a 7.1 home theater. The room is 16 x 18 with a 10 foot ceiling. I currently own 2 HSU TN1220HO driven by a 600 watt pro amp so I won't be needing a sub. Main juice is provided by a Denon 3802 driving the rears and used as a processor and either an Adcom 7500 or Marantz MA500 monoblocks driving the other 5 speakers. Question is: In a setup that utilizes the 80hz crossover, is there any benefit to moving up to the larger floorstanders as opposed to the M22ti for the fronts? I own a set of high quality 24 inch stands, so the cost of the stands should have no bearing on the response.

Also, I've heard a lot about terrible off axis response (huge suckouts) with MTM centers used horizontally. Seems like guys like Nousaine claim it's the nature of the beast. Do your centers suffer the same fate and does the VP150 eliminate these suckouts due to its rather unique layout?

Finally, with 2 woofers a tweeter and a rather large box, I find it curious that the M22's only weigh 14 pounds. How thick are the panels that make up the box and what material are the boxes made of?

Thanks

This is a great system you are pulling together. The only advantage to the fronts being towers, assuming the 80Hz cross over is in use, would be the M80s for getting more overall achievable output. With the power you are using it may be worth considering.

You are correct about the Center Channel problem when the tweeter is in the middle of the woofer array. The VP150 does eliminate this problem because the tweeters are on the outside of the array.

The M22s are very heavy. They are made with 3/4" MDF front, back, and sides. I think I will have the 14 lbs checked for accuracy.


Ian Colquhoun
President & Chief Engineer

So, if I want to hit reference level during movies in my 16 x 18 x 10 foot room will the 22's do it crossed over at 80?

Thanks

The M22s will do it. The dual tweeters in the M80s will take you to an even higher level than the M22s but I think it is important to keep in mind that we are talking extreme levels that the M80s will go to and that would be overkill in your room.

Ian Colquhoun
President & Chief Engineer

Tony I would appreicate a few words on the 3802 I'm considering buy either that or the Onkyo 797. I'm only waiting because I don't know which one to get and any info would help
Thanks
Joe Nardi

I got the Denon at Uncles in NY. I paid around $800 shipped. I got the Denon because I was it sure it offered adjustable Dolby PLII paramters. Not sure about the Onkyo. Also, I think Denon's amps tend to be a bit more robust and the 3802 has 7 channels of amplification if you need them. The Denon is quite a smooth sounding but powerful piece with very quiet dsp's and analog pass through. I think it's a great piece for the money.

Why would you ever crossover tower speakers at 80Hz if it was not necessary? I know most receivers have only one fixed crossover point from their sub output (usually at 80Hz) but there are other ways to connect the sub.

Wouldn't it be better (defined as taking advantage of the full range of the Axiom towers) to use either the sub / receiver's line level in/out or speaker level in/out? This way you could use the sub's variable crossover and take advantage of the tower's bass (ie. set the sub at ~ 40Hz). This will work with most receivers by setting the receiver's speaker settings as follows: front speakers to LARGE, the rear and center to SMALL, and the sub to either OFF or NONE.

In this configuration the sub handles 40Hz and below and the front towers handle 40Hz and above (any bass below 80Hz originating in the rear and center would also go to the sub - that's why you set those to SMALL).

I know this post is overkill on a trivial matter but I happen to be very curious about this subject (as well as dismayed that more receivers, preamps and/or processors do not integrate either variable crossovers or more fixed point options into their bass management - which would simplify the solution to this problem).

Thanks for your thoughts.

George

George,

Here's a thread that sold me on setting my mains to small, even though they are capable of decent bass (M60Ti). Plus, the small setting takes a load off the reciever. Also THX spec is an 80 Hz crossover. (although it would be nice to be able to change this for tweaking purposes!)

http://www.avsforum.com/ubb/Forum3/HTML/003524.html



--speedy

I have experience connecting sub's to receiver subout connections (which uses receiver's crossover) and via receiver main-in/pre-out connections (which uses sub's crossover). For most powered subwoofers, the trade-off of getting a lower crossover and using your mains better low-end capabilities versus having a (usually) higher crossover built-in the receiver is volume control convenience. Many subs do not have a remote control, though most do have a volume knob -- when using the sub's crossover, for music, you'd likely have one sub volume setting, though for action movies, you'd likely want to turn-up the sub volume a bit for thos explosions. When using the receiver's crossover, you can control the sub's output setting via the receiver's remote control. Convenience versus potentially better sub/mains blending.

Why to buy floorstanding speakers at all?
If you have a good sub, just set the x-over to 80hz, all speakers to small...

I have a receiver that has a variable cross over setting.
I have the MT80's and the EP175.
The manufacture of receiver told me to set the cross over at 60 hz.
Ian, do you agree with this? Or do you recommend another setting perhaps 80 Hz?
Also does spikes give you a advantage over rubber feet? If so why?
Thanks

I have a receiver that has a variable cross over setting.
I have the MT80's and the EP175.
The manufacture of receiver told me to set the cross over at 60 hz.
Ian, do you agree with this? Or do you recommend another setting perhaps 80 Hz?
Also does spikes give you a advantage over rubber feet? If so why?
Thanks

You cannot damage anything by either setting (60 or 80) -- try 'em both for a while and keep the setting you like most. There is no real perfect answer. Only your preference. Have fun with it!

Spikes will cause a clarity in the sound produced by the speakers. I am not entirely sure why, but I think made a big difference in my setup!

BBIBH probably has the answer, so I am sure he will be glad to help us!

abcd

Spikes are used in many speaker installations. They are used to decouple the speakers from the floor. Our friend Sir Isaac Newton is alive and well in many areas of audio, including the speaker arena!

Remember that a speaker is simply an electric motor. The motor movement is in and out, based on electricity applied. The outward movement produces a sound wave that radiates into the environment - your room. The backward movement also produces a sound wave that is partically trapped inside the speaker cabinet. Designers have several methods of dealing with this trapped energy, such as ports. This redirects the energy out into the room, and if designed correctly, enhances the sound. If done incorrectly, it can detract from the sound. Anyway, the energy is contained,will escape one way or another, and can cause resonances within the cabinet and environment. This is really wasted amplifier power and speaker movement if it can not be utilized.

All materials resonate (vibrate), and spikes isolate the sound energy from moving from the speaker to the floor. The contact point is very small, and most resonant frequencies can not navigate through that contact point. If allowed to travel to the surroundings via vibrations, the surrounding materials can also vibrate. This domino effect can cause similar enhancements and detractions to the sound as our example of the speaker cabinet.

Similar concepts are in place when using spikes or isolation methods under turntables and other equipment.

Regards,

BBIBH

Technically the 60 Hz setting is the correct one to use as per the recommendation of the receiver manufacturer. However this does not take into consideration your particular room acoustics and for that reason I would at least give the 80 Hz a try and see what you think. The key with either the spikes or the rubber feet is to keep the front baffle of the sub woofer off the floor and avoid a coupling effect that is not desirable. The spikes are mainly used for carpeted surfaces as they will penetrate to the sub floor underneath and add stability. There is also the argument that the spikes, due to their small surface area will isolate the sub from the floor better than the feet. From a strictly physics point of view this is correct though the difference may be hard to hear and probably not worth ruining your floor over.

Ian Colquhoun
President & Chief Engineer