Axiom Home Page Forums General Discussion Advice from Axiom Owners Identical Fronts

HI Everyone. First time poster here. I am hoping for some advice from some Axiom owners as I am hearing conflicting reports on what I should do. I am currently finishing my basement and putting in a home theater. My initial plan was to buy two in cabinet m80's and a vp180 in cabinet for the front stage. I am putting the 180 behind the screen and the 80's into custom pillars flanking the screen on both sides. When I went to buy the screen the gentlemen asked what I was speakers I was buying and why. I told him and he immediately asked why I would not use a m80 as a center. It should disperse the sound horizontally better since it is a vertically oriented speaker and will perfectly match the left and right. So, which would be better. A in vp180 or an m80 and why? Thanks in advance for everyone's help. And I do have room for either set up since I am using an AT screen.

Welcome,

When possible, you should put 3 identical speakers as a front sound stage, there is simply no better match than that. A vertical speaker as a center will also give you a much better off axis response than a horizontal one. People settle for horizontal speakers because in most cases it is impossible to put a vertical one. I your case you should definitely go with a 3rd M80. For once the salesman was right

Thanks for the quick response. My seating position will be a little under the center of the screen vertically. Should I try to get the tweeters ear level with the listening position or centered with the screen. To get them ear level I will have to orient the m80's upside down. For that matter, maybe I'm splitting hairs here, but if ear level, being the m80 has 2 tweeters and two midranges, if ear level is the way to go, should I try to make ear level between the tweeter and mid woofer.... I may really be over thinking this

i got M80's and sit about 6 ft away from them.
my ears are just about halfway between the lower tweeter and
the top midrange.
i checked to see if i was missing some h.f. by increasing the treble a little, but it was not necessary.
i guess the tweeters have a good enough off axis response downwards that a few degrees does not matter.

3 identical vertical speakers is tops.

I agree with Bruno; if you're already committed to the AT screen, just get 3 in-cabinet M80's. Not sure what to tell you about your upside-down v. right-side-up issue. I guess I'd need more information about the room to have an opinion. How far back will you be sitting? How high is the ceiling?

I think you'd want the tweeters - generally - at about ear level, but that having them "a little" above ear level would probably be fine if you're far enough away.

Sounds like a very exciting build; I will look forward to following your progress.

I agree with everyone else, but will make one other point: If the speakers are behind the screen, I would opt to get the tweeters mid-screen, as that's where you'll likely "identify the sound.... and it should seem as if it's coming right off the screen.

Depending upon how far back you're sitting from the screen, that likely won't put the tweeters (too) high, though that might happen if you're sitting really close.

I'll be sitting anywhere from 10-14ft back. The screen will be 120 inch diagonally. The only one to be behind is the center. I am also planning on doing two in cabinet ep 500's below the screen so the screen will be off the ground roughly 24 inches. That is where the m80's will start at about 24-26inches. If i turn them upside down, I was going to turn them upside down and center the entire speaker with the height of the screen. this would put the tweeters close to ear level, but below mid screen level. Oh and the ceiling is just shy of 8 ft. The room is 18 wide by 19 deep. I like the idea of having the tweets mid screen if it is possible. I'll have to go measure.

Does anyone know if there will be any disadvantages to having them upside down?

Whenever I get to that point in my downstairs HT project, I plan on trying them one way, then mount them upside down and try them the other way. Then whichever way I like the best is where they'll stay.

BW, welcome. Although careful crossover design and configuration of drivers has given good results in the VP180, as Bruno pointed out, the best arrangement, if possible, is identical speakers across the front. Use a vertical M80 center.

As to height of the tweeters, yes, you may be "over thinking this". If the tweeter would be about 2' higher than your ears at a 12' listening distance, the downward angle there calculates to be about 9 degrees. As Jacques(J.B.)found in his listening test, floor standing speakers typically have good enough below-axis dispersion that listening at that sort of angle isn't a significant problem.

Hello bwallen,

I'd advise you not to invert the speakers. They are designed and balanced to sound their best in normal upright position. It also isn't how the blind listening tests and anechoic measnurements at Axiom are conducted--with inverted speakers. They will certainly sound different; whether or not the sound and sonic balance will be degraded, I don't know.
Also, the off-axis dispersion of the M80s is excellent, so you don't need to have the tweeters exactly in line with your ears. I also wouldn't invert them because it would put the woofers at the top, so they won't benefit from the boundary reinforcement for the bass octaves, thereby altering the carefully designed sonic balance in the room.

Regards,
Alan

Alan, wouldn't they get boundary reinforcement from the ceiling?

Alan,

How high above the listening position would be acceptable? I will be sitting 10-14ft back from the screen.

For that matter, could you turn the 180 in cabinet vertically and use it for your front 3? This would seem to solve the height issue for the tweeters, but may present other problems.

No. This would anger the speaker gods, who would strike you dead the next time you stepped out your front door. Johnk will be along shortly to provide the details as to why this would anger the gods so...

Yes, BW; the "other problems" would involve the fact that the crossover and the driver arrangement in the VP180 were designed to optimize it when in a horizontal position. It wouldn't match the performance of a vertical M80 if it was turned upright. As my previous reply indicated, there really isn't a significant "height issue" in what you described.

Hi Tom,

No, not unless you had the speakers up so high that the base of the M80 was against the ceiling.

Regards,
Alan

Hi bw,

Given your listening distance, you'd have quite a bit of flexibility. I'd estimate you could have the tweeters as much as 18 to 24 inches higher and still be within the very tight "listening window" of the M80. The off-axis frequency response of the M80s remains very consistent to as much as 30 degrees off-axis (left/right and up and down) at a distance of 2 meters (about 6 feet), with only a little attenuation of the very highest frequencies even at 30 degrees.

You can see here the NRC anechoic measurements of the older v2 M80
http://www.soundstagenetwork.com/measurements/axiom_m80v2/

The new tweeters of the Axiom v3 series is even more consistent off-axis than the v2 series. The curve posted on the M80 v3 spec site is a composite of listening window measurements of the M80v3 in Axiom's own anechoic chamber, which duplicates the NRC chamber. The curve is significantly more linear than the older listening window curve on the Soundstage site.

http://axiomaudio.com/gallery_disp.html?image=M80_freq.gif&title=M80

Regards,
Alan

Thanks Everyone for the help. I have been dreaming of this theater for years and now that I am finally doing it, I want it to be perfect!

From my listening position, the speakers tweets will be 18-24. I will have to scan in my crude drawing of my front stage and see what everyone thinks.

The front sound stage will be in a false wall I'm building. I was considering incorporating 500's below the screen. Will these bad boys cause my screen to vibrate? Also, will I need to put anything in the speaker cavities of the in cabinet 80's to help with vibration or can I set them directly into the 2x4 structure?

Hi,
There is no need to put anything in the M80 In-Cabinet cavity. Simply make sure that all the surfaces of the speaker enclosure (except the bottom one) don't touch your false wall structure. Will you be using the EP500 In-Cabinet subwoofer model as well? I don't think that the sound waves from the speaker will seriously vibrate your screen. Howver, it might shake and/or move your projector it it is resting on a shelf. I had to lower the volume on my subwoofers because the projector would jump on its shelf. I have a friend who had to put "blue stick on" on the legs of his projector because it would slide on the shelf. Very powerful these Axiom subwoofers!

About flipping the in-cabinet M80's. My 2.40:1 screen will probably be mounted very close to the ceiling. Probably putting ears in line with the next to the top woofer, or bottom mid-range. Inverting the speakers may work best for me. But, I wouldn't know until I've experimented with the arrangement.

What is the minimum amount of room needed between the m80 and the screen?

Also, will it be an issue if part of the bottom of the speaker where the port is is behind the bottom part of the screen where the border to the screen is. Hence having a partially hard surface covering 1/4 to 1/2 of the port 3-4 inches away?

In regards to boundary for base, if I did invert these suckers, they would almost be on the ceiling, and it would put the tweets ear level. I'm really having a hard time as this is being built seeing that the tweets will be 18-24 inches above my head if I keep them right side up. I really need to snap some pics for everyone to see.

you can put the M80's right next to any flat panel; they are not sensitive at all to magnetic fields (the CRT's were).

other people will answer the rest better than me.

The center is going behind a projection screen.

Hi bwallen, The port requires only two inches of space to breath freely. Your installation will not suffer from this placment scenario.

Thank you. How about Inversion of the m80 in cabinets. I have the 800 in cabinet going below the stage wich is why the 80 are having to go so high. Where the stage is it is 7 ft tall total. Inverting is the best option to get the tweets in the right place, but obviously I want these guys to sound thier best.

I have not auditioned them installed in such away. I suspect that their performance will be quite similar if not identical. You will need to try them both ways before final installation.

JC, isn't that part of the fun in having a a EP600/800?


BTW, i never had this problem of "projector bounce" even when i had my EP600 in a 120sq foot barracks room (my projector was sitting on a shelf at the time), and the gain on the amp set to the "mid" position, at least i didn't notice it if it did happen.

Hi dakkon,
In my dedicated Axiom Home Theatre room which is less than 2400 cubic feet. All the boundaries (floor, side and back walls and floor) are made of concrete with exposed surfaces made of drywall and carpet. Originally with two EP500 and two EP600 I could make the picture shake. It can't be the screen it is a painted type (Goo Systems). It might have been my eyes shaking in my skull . . .

Currently with four EP800 (thanks again Ian) I am experiencing a superior more satisfying bass performance at a lower volume level. Perfect bass for movies and music . . . heaven, I’m in heaven la, la, la, la . . .

Bwallen,

I responded to your PM. Sorry it took so long but I was out of the country.

In addition to what I said in the PM the best thing you can do is experiment and listen for what sounds best to you. Additionally I’ve found that my M80s sound better when raised a little so that the tweeters and midrange drivers are higher than the furniture I sit on. I hear much more ambiance and get a better 360 degree soundstage when the furniture isn’t absorbing all the direct sound waves before they have a chance to bounce off the back wall.

Intersting, I might have to try raising my M80's up.