Axiom Home Page Forums General Discussion Advice from Axiom Owners Ok so another sub question how many

OK my room is going to be 11.5w x 18.5L x 7.5h

SO wondering now would for the size of the room I be better with 4 EEP400's or 2 EP500's

obviously as posted this is for Movies 100%

If you have the space for the 500, get the 500. The only reason to get the 400, is if you don't physically have enough room for the 500, or if someone tells you that you can't have a speaker that big in the house.

I have 2 350's in a room bigger than that currently, only because my 600amp is getting fixed, and it sounds fine. You may find one 500 would be adequate, but two placed correctly in the room and setup appropriately will give you better smoothness in all seats.

What are you trying to accomplish with the multiple subs? You will fill the space with PLENTY of bass from a single decent 12" sub. End goals are a much to know here.

Do you just want louder with some peak/null control? Then go with the two 500s with one centered up front and one centered on the rear wall (or both side walls, but the others are acoustically better according to some).

Do you want to tame the bass/LFE madness found in all rooms and can sacrifice the space, then go with four EP400s with one centered on each of the four walls.

I want nice smooth even bottom end.
I have two now and love it.
the only thing I might consider is the EP600. Verticle, directly in front of me under the VP180.
I just thought maybe the four EP400's would fill the room nicely.

its not that big

I am guessing that you are looking for that satisfying ummmph the movie creators feed to good subs. IF that is the case, go with the 600 or the two 500s. I have a single 500 in the bonus room. It has a knee wall up to about 4 feet then a 45 degree slope to an 8 foot ceiling. 18 feet wide by 25 feet long. IF I were to crank the one 500, it would likely boom the pictures off the wall. I don't - I keep it even for music listening - but the LFE feed still gets down there on the Action Adventure movies.

Ok, so I am down to one EP600 or two EP500.
Probably better off with two EP500's though.

Unless his seat is in a null location and then he gets nothing. Doh.

OK. That is solved for the most part by the "Subwoofer Crawl" and such for best placement, but just sayin'....

I was a very happy, single-subwoofer person for 9 years. Then I added a second matching sub, and not only can have louder bass, but it has smoother response in the room, and I nearly reduced all overpowering peaks and the "non-existant despite a large powerful sub" nulls.

So watch placement if going with a big beast and you will probably be OK.

I will leave you all with the following information. This is NOT my information, but my gathering of numbers and notes from real industry experts. I used these notes for my final tweaking and such, and for future notes (so that I don't have to find this again.) Note the subwoofer section.

------------------------------------------
SEAT LOCATIONS:

To avoid harmonic peaks and nulls in the room, seats should be placed at one (or more) of the following locations.

WIDTH:

.20, .32, .45, .55, .68, .80 of the width of the room

LENGTH:

.55, .68, .80 of the length of the room (away from the front solid wall)



FRONT SPEAKER IMAGING:

Locate the front left and right speakers and the center of the main seating such that it forms a 45* angle.

Do NOT sacrifice the above seat location calculations.

A 45 degree angle gives good sound imaging.

Toe-in of front left and right speakers helps since most speakers perform better that way with mid & high frequency dispersion.

(I had a graphic here that just showed an ideal angle of 45 degrees when measuring the angle of the width of the front R and L speakers from the main seat.)

Like tow-in of the left and right, aim your center speaker, up or down, so that it points towards ear level in the listening area.

Below screen is better than above screen for center channel imaging.

It usually is closer to ear height.

Height of front speakers should be around 40” from your desired measurement point of the tweeter, midrange, or somewhere in-between.

Do NOT put the center channel more than 2 feet above or below the front left/right speakers if at all possible.



SUBWOOFERS:

Standing waves are a big issue with low frequencies.

To eliminate as many standing waves as possible, you need 4 subs.

Place 1 in each corner, or 1 in the middle of each of the four walls.

If you can’t do 4 (10”) subs, do two (12”) subs with one in the middle of each of the front and rear walls, or the middle of each of the side walls.

One large 18” sub < four 10” subs

I sit 11' from the front
5'6" centre from the sides walls.
The seating is a three movie style seating, I am in the middle
My imaginary friends are on the left and right

the rear wall being constructed is 5'6" behind and I am 5'.9" behind where the QS8's will go.

I am now running co-axial cabling for the subs.

two runs up front, two runs to the rear wall and three on each side wall in increments of 6'

So two subs I can pretty well put them anywhere, but I really, really don't want a two ft sub jutted out into the middle of the room.

and 4 8" sub are greater than a 15"


Thanks NickBuol

My family room is about the size of your room.. I have a pair of EP600'S, and they fill the room very well.. granted that isn't exactly one of your options... but, I would recommend considering it.

I'm on the wire between PB12 plus or a EP500..

has anyone compared these subs?

hopefully axiom will come out with new subs soon... they have been awfully quiet on these forums lately

Hey, those are just my notes, exactly from the words I heard from audio experts who study this stuff for a living.

Sorry , wasn't meaning anything by it. I know I heard that before. Also, the one I mentions. 15 x 3.14 = 47.1 10 x 3.14 x 2 = 62.8 and 8 x 3.14 x 4 = 100.48 . So technically four 8" subs should move more air than a 15" by 2.5 times.
Also, will have twice the wattage power than two EP500's has 25% speaker area. Is tighter in the bottom end, quicker.

My two 10 subs fill the room very well. the only thing is they are just slightly above entry level.
I could very easily probably get by with 4 great 10" subs better than two 12". but, then at twice the cost also

By, the way thanks for sharing that info. I like the ratio for seating.

I sketched out my room on graph paper. Then entered the seating and put my speakers at the 9' seperation. and made my triangle, but 9' is too close. So, it is not perfect, but I can toe the speakers in and out as I need. then placed the sides at 90deg and the rears at 115 deg. with a protractor

It doesn't quite work that way. You're missing a dimension, the movement of the cone, which is probably the most important. Think about this: a tweeter has a .75" dome. So 20 tweeters should equal a 15" sub. But it doesn't; a tweeter has such a small amount of movement. It'd take a whole lot more than 20 to get them to produce a 15 Hz tone at any audible level.

It would seem that with this logic, a room full of tweeters should put out great bass.

The quality of the sound of my 2 EP-400s for 'music only' is simply outstanding; however, I've never used them for the high demands of HT. Four undoubtedly will have enough horsepower for the rigors of HT as was demonstrated here in 2007:

http://www.audioholics.com/subwoofer-reviews/axiom-audio-ep400-subwoofer

The EP-400 has been significantly tweeked since this article in 2007. Mine are the latest version that continue to impress me with their exemplary performance. Get your out wallet if you purchase four though, ha!

Personally, I would go for 2 X EP500s for HT - way cheaper too...

TAM

Thank You
taken right from the article
According to Ian Colquhoun (President of Axiom Audio), the EP400 was produced to fill a specific need: to pack real subwoofer performance into the smallest possible enclosure. Ian and crew demonstrated that four subs are better than one at our 9th Annual State of the CE Union Event on October 6th, 2007. In a reasonably sized room such as the demo room they utilized (roughly 400ft^2), they were able to utilize 4 EP400's strategically located equidistant from the listening area against the midpoint locations of the 4 walls. Using a switching device to switch between 4 EP400s and 4 EP600s located in similar areas, it was nearly impossible to hear or detect a difference. The EP400s were playing just as low and loudly into their demo room validating their claim that the EP400 has similar extension of the EP600s when played at similar volume levels in a moderately sized room. For those wondering how they can cram 4 giant boxed sized subs into their theater room to take advantage of even bass response in all listening positions, the EP400 may just be the answer to your problems. We look forward to examining this new little GIANT in the near future via a formal product review.

Yup. It just comes down to what you want to spend...

TAM

You guys are taking things too literally.

Honestly, I would stay away from 8" "subwoofers" To me, those are larger midrange.

The point being made by the guy was that instead of one massive and powerful sub, 4 smaller subs (real subs) would give better and more even response in the room. A larger sub should go deeper, but if you are sitting in a peak or a null that can be very bad.

Ideal situation would be 4 larger subs like the 600s.

It certainly is an impressive midrange if it can reach cleanly down to ~20 Hz. My EP-400s happily do that but for HT it takes more of them to achieve the excessive, overblown SPLs that many people seem to want.

I'm not one of them. That's why my modest 10" Velos serve my HT just fine & can rattle things in my room to annoyance levels...

TAM

Well if I had $10,000 to spend on subs this would be a moot post.
DOn't forget I am not trying to fill a large room either 4 EP600 would be going over board for a room this size. ANd if I had $10000 to spend on a sub system I would imagine I'd have another $10,000 in speakers and a AV. and if I spent $20,000 on a system I figure I would probably have enough money I would have a bigger house therefore a much larger room

I really want to see what's next from Axiom before replacing my subs. For the moment they are doing a great job. That said I can see a large enclosure or two in my future.

My comment about the four EP600 subs was not directed at you. It was for those that make comments about a room full of tweeters (You know who you are, meow ) and the like.

And for some others posting, there is more to it than just SPL. Some people don't care about anything BUT SPL, and that it their personal preference and I am not going to say that what they like is wrong for them. This topic seems to have started by one person's desire for great low bass, and better, more even bass in the room (thus multiple subs vs. some huge 18" monster). I was just trying to offer help, but alas, my "notes and highlights" from a lot of scientific research came across apparently as a bunch of crap or something. I will bow out of this discussion at this point since I clearly out of my mind.

It's not just SPL, it's extension. If you don't have a sub that can produce 20Hz, you're not going to hear or feel it no matter how many of them there are.

It isn't about max SPL, but being able to reproduce lower frequencies with at the same output level as the upper ones.

Just because you have the same surface area of cones doesn't mean you have the same displacement. Lower frequencies have longer wavelengths, and in order for a driver to be able to create an equal amount of pressure for a lower frequency it needs to push just as hard as it does for a higher one, but move for a longer period of time. That translates into excursion. Larger drivers have larger maximum excursions.

More drivers, placed to interact with more of room will definitely get smoother response throughout the room, but you need to have the same total displacement to create the same sound pressure levels. (See infinite baffles: a large number of smaller drivers, using the total of their smaller excursion to produce very low frequencies.)

Personally, I've gone from one 12" to dual 8s, to purposefully lose the ability to reproduce infrasonics, because I live in an apartment building and the neighbors were complaining. So I moved the tactile frequencies into a device designed just for that, and let the "subs" handle only the lower, audible bass. (Once I get moved into my own place, I want to be able to pressurize the room 5 times a second to levels of 120 dB.)

OK. I couldn't stay away. I just felt unsettled because I wasn't explaining things worth a crap. Let me start over. I am going to somewhat simplify, so be nice people.

4 subwoofers > 2 subwoofers > 1 more powerful subwoofer for more even room response BUT, you may lose some low end depending on what the specs of the subs are.

OK, that should kill off the "room of tweeter people" (Really? Jumped to that extreme.) Whew.

Now, back to the original poster's question, looking at specs for the EP400 and EP500, they are BOTH capable of sub-20Hz sound, so for this discussion (and as I mentioned back a couple of posts about getting deeper bass) the sub count "rule" is very viable. with the 4>2>1 sub, when all subs are capable.

Again, my original notes didn't go smaller than 10" and clearly nowhere near tweeters (sorry, I guess I am bitter).

I wish I could just go back and let you guys just yammer on about it. I honestly tried to bring some other insight and research into this, and for about the 3rd or 4th time I am apologizing again. You guys got cranky about some poorly explained information. Never again. Now you will all have to suffer through my long dissertations on everything instead of the "Cliff's Notes" version. I'm out. Sorry (5th time?) for the confusion. I really am not as stupid about this as you all think I am now.

nick:

I fully appreciated all of your significant research, contribution & effort that you put into explaining the ideal requirements of HT setups. You certainly did not come across as unintelligent at all. Sometimes posts that are made to be humorous or tongue-in-cheek don't come across that way.

Where you lost me a little was dismissing little monster subs like the EP-400 (there aren't many 8" subs out there as capable as this unit) as being not up to the task. Having said that, I agree with you that for HT I probably would still choose 2 X EP-500s over 4 X EP-400s just for 'bang for the buck' reasons alone; however I surmise that either model would work just fine for most HT rooms as was proven in the AH article...

TAM

We love ya', Nick.

Please. Sorry about the tweeter comment. I was just surmising in a whimsical way. I guess you have to get used to me then put me on ignore like most others here do. lol.

I wasn't trying to be absurd with my tweeter comment, but just trying to give an example at the extreme opposite end. I find it easier to picture what small differences appear because of small changes, by visualizing what happens to a system as it's taken to the limit.

talking about subs... I like this listening test that was done back in 2005... Lab test results ep500 & pb12 plus

As an aside, can I use a powered 12" sub that is of a different brand, and is quite old, and an EP 500 to smooth out the bass frequencies in a room or would it be best to stick with the EP 500 (2 EP's are out of the question)?

Sure Lee, it can at least be tried. The best results from using two subs to partially cancel room modes(e.g., by locating them at the midpoints of the opposing side walls)are achieved when the two subs have essentially identical response at the mode frequencies. However, as long as they each have some response at a given frequency, partial results can be obtained and an overall improvement achieved.

That is good news...thank you John. I can easily adjust the frequency crossover on the subwoofer's amp. It is quite sophisticated for its time ('79). Another question I have is the application of two sub's to my main entertainment medium...music, and more specifically, as you know John, classical. I would rarely use the system for movies, although once I set up a 5.1 or 5.2 system I may be tempted to watch movies with the system. I am guessing that having two sub's would be less of a necessity for music than for movies, and for now I could not place the sub's properly for the best effect, and they would not match each other as pieces of furniture. If you could comment on that it would help me to decide what to do. Thanks

I was thinking the same thing as I currently have two ESW10's which would be great for in the rear. I can then use two EP500 up front or an EP800. but thought that the two ESW10 would not be as good and mess up the sound qaulity

In my experience (just me moving stuff around, changing settings 100,000 times) more subs are better even if they don't match.
At the moment I have a 12",10" and 8" sitting where each sounds its best. Sort of a staggered triage in my room. I'd add the fourth (second 10") but I can't find a way to get it here for a reasonable cost.
Of course having identical subs would be ideal but isn't always an option.

Today's (juvenile) out-of-context quote.

Unless one sub is really small, there should be no issue with multiple subs of different manufacture and configuration. I have four subs from three different manufacturers and a couple with different power levels. In my opinion, the only relative constant is that they all can ideally reach the "approximate" equivalent range in the lower HZ(35 HZ and below)level comfortably.

In addition to smoothing out the bass in the room, the other advantage of multiple subs is that you can attain the same SPL levels as one sub by itself but at a relatively lower volume, so you are not driving each sub as hard as you would one on its own.

Lee, there's no difference between music and movies(or music in movies)as to the benefits of using two subs. Either may have significant low bass at a moment in time.

Of course the appearance isn't identical, but I assume that you wouldn't be greatly disturbed by that. Some type of placement(e.g., both up front about 1/4 of the way in from the side walls)can almost always be used which would give satisfactory, although not optimal, results.