Axiom Home Page Forums General Discussion Home Theater Ian and Tom Video interview re: A1400-8 & EP400.

Hey guys,

This just went up today at audioholics.com.

the Video has a really nice shot of the new computer speakers in a gorgeous finish...A very informative interview!

Enjoy!

Click me!

Looks like Ian isn't a big fan of eq'ing software to even out bass response

Thanks for the link, Hutzal!

Interesting bit there is that Ian says that a single EP400 doesn't have all that much output (of course, all that much output for Ian vs all that much output for me...), but has great output when you start using multiple subs.

great interview.. very informative and those comp speakers look sweet!

I believe he meant compared to the relatively huge EP600 which has powerful output. Keep in mind that the EP600 with its 12" driver and 600W amp is over 5x as large by volume as the 400 with an 8" driver and 500w amp.

Regarding output, one way to look at it is that the EP600 is twice as loud as the EP500 which is twice as loud as the EP400. You would need to colocate a pair of EP400s to match the output of an EP600, the extra 6db coming from the coupling effect of the 400s in close proximity. Separating the subs by much more than a couple of metres loses much of the coupling effect but you get better smoothing of room nodes. That's why he is recommending the use of multiple 400s, ideally 4 of them, as the best HT sub solution which reduces the need for electronic equalization and provides all the output you would want.

A 10dB change in SPL is perceived as twice as loud.

When I compare the 350/400/500/600, their performance is only marginally differentiated. Why would anyone buy anything other than a 400 given the information in that graph? The 500/600 need to be more differentiated in my opinion.

Has anyone tried running dual 600W amps on their 600 ?

Mo, John may have been referring to the acoustic power being twice as high, rather than the result actually being subjectively twice as loud(generally said to require a 10 dB increase, as you point out), although he did use the term "loud". The 3dB increase which two widely separated speakers playing the same sound produce does involve twice the acoustic power(and twice the total amplifier power)but the 3dB increase, while noticeable, is far from the subjective "twice as loud" standard.

Hey Mojo I was referring to output and SPL A doubling of sound pressure level means the audio signal level is increased 3 dB ie. there is twice the acoustical energy. However as you mentioned our hearing does not work linearly and that 3 dB or doubling of SPL does not seem to sound twice as loud. Our perception of twice as loud occurs at roughly a 10db increase even though a doubling of SPL occurs with a 3db increase.

It would have been more precise to say the EP600 has about twice the max SPL of the EP500 which has twice the max SPL of the EP400 as can be seen from the specs on anechoic and in-room SPL. http://www.axiomaudio.com/specs_subwoofers.html



Depends on your perspective. A doubling in SPL means alot in your audio system. A more powerful sub means less likelihood of compression other things being equal. For me the difference of 3db output and 3hz extension between the 500 and 600 is very significant in that the 600 can output twice the energy and run deeper. Between the 500and 400 the gap narrows in extension but the 500 can still output double the energy of the 400. The 6db difference between the 600 and 400 is nearly 4x the acoustical energy being output. Those differences for a single sub may not appear like much on paper but they make a BIG difference in your audio system.

What I find interesting is the discussion of how 4 600s and 4 400s sounded so similar in a moderately sized room.

Hi John. Thanks for also adding the clarification. We must have been typing at the same time.

Jake, you've listened to and played with more subs than me so I trust and respect your opinion.

I'd really like to get my hands on a 400 and compare it to my 600 in my 4,000 cubic foot space. I'd like to hear and feel for myself if there is a significant audible difference.

Well Mojo thankyou for your kind words. Pretty soon I hope to compare single and dual 400s in my HT room next to my 600, and other subs. If I'm lucky I'll also get to put the a1400-8 through its paces. I'll post my perceptions and some data.

So what is stoppng you? I want to hear one too! It's a liberal return policy...

That would be awesome. Thanks.

I'm kind of worried that the 400 will sound similar to my 600. And actually being a sealed design, it may even sound better.

John (jakeman), in the comparative chart for the various Axiom subs, the 3 dB sequential difference from EP400 to 500 and 600 appers to be in max sound pressure level. That 3 dB difference does not seem to be the difference in "audio signal level", which would indeed imply doubling of the SPL. If the SPL is not doubled, why would we assume twice the acoustical energy going from one sub to one higher in the sequence? I am not trying to dispute your point, just trying to understand your reasoning and the chart. Thanks.

John

PS: is there yet a 4th John who would like to join in this discussion?

You say that "the SPL is not doubled". It is doubled. A 3dB SPL difference does indeed double the acoustic energy.

Perhaps I'm not understanding your question. But then again, it wasn't directed to me .

Mojo,

What threw me off was that "SPL" is not doubled by going from say 112dB to 115dB, but the "energy" is doubled. I was trying to read more into jakeman's (John's) post and when he used "doubling SPL", I didn't think he meant this. I think he meant doubling the energy, which is clearly the case among these 3 subs (or nearly anyway, since the difference is 2dB between the EP500 and 600).

John

Edit: SPL/energy is indeed doubled from 112 dB SPL to 115 dB SPL. Use of "twice as loud" and "twice the SPL" interchangeably on John's post threw me off.

This paper that John (jakeman) has pm'd me a while back was quite interesting. Four subs is perhaps the way to go if one has the room, funds, and WAF in their favor.

John

The WAF would definately be higher with 4 EP400s than any other sub I can think of. Now just to get that cost past the accountant......wait that's me..... but the CFO isn't me.

Why worry? Just enjoy that awesome 600. Its impossible to say without hearing it but I suspect the impulse response of the sealed 400 will be different than the ported 600. But even there its not clear without listening and examining a graph which will sound better in your room when blended with your speakers. A well designed ported sub can also exhibit excellent transient behaviour which contributes to that "tight" sound.

I know Axiom is great about its return policy but I'm planning to borrow a couple of 400s and the amp by picking them up in Dwight. I wouldn't put the company through the cost of shipping and administration unnecessarily. I heard the ported version 400 at the Axiom show last summer and it sounded very good.

ihifi(John) yes we need more John's in this thread.

I was trying to communicate the idea in a less technical manner when I said "Regarding output, one way to look at it is that the EP600 is twice as loud etc...." but Mojo is right about "perception" of loudness as being different that an SPL doubling.

That Harman article is a terrific article on the benefits of multiple subwoofers.

A pair of 400s as an alternative to a 600 will be a neat comparison. Stacking the 400s gives you the output of the 600 because of coupling. You have the flexibility of separating them for smoother in room response but then have only half the output with less extension than the 600. One other interesting attribute though is the flexibility to set the 400s as stereo subs with monitors or the smaller Axiom speakers.

I'm really looking forward to listening to them hopefully next week. I'm heading up to Dwight this weekend to spend a couple of days on the lake.

Jakeman,

Make sure to take alot of pics and post a lengthy review...I wish I could be there with you to put the dual EP400's through their paces.

I was also very curious about the new EP350 v3, dual EP350v3's will give you 600 watts of power, and a sub that reaches down to 18hz...not bad at all! especially for less than $1400.

Jakeman,

How is THD and group delay affected when you stack subs?

Robb,

Do you know what you're giving up by going dual 350s vs. a 600? Notice that the 350 doesn't have an SPL deviation spec or a graph.

I was thinking about pming alan to get a graph up for the EP350v3. Maybe he'll see this post.

The reason I am so curious about the dual 350's is that you can get 2 of them for just a little more than an EP500. And you can place your dual subs on opposite walls obtaining a smoother bass response in the room. I think the trade off is worth it...I might be persuaded to get two EP350v3's instead of an EP500.

You read my mind!

Mojo one of the main benifits of multiple subs is more headroom and less strain on the individual subs. Accordingly at any level of SPL you should see an improvement in distortion and group delay. You create extra headroom by co-locating the subs due to coupling. The major drawback is the lack of room smoothing when you have subs located throughout the room. The trick is to have the subs close enough for mutual reinforcement and far enough for room smoothing. Easier said than done.

Lots of output for the $$s in the 350v3 however it doesn't have the DSP circuit. And who knows how the 350v3 compares with THD or group delay. It would be great if Axiom would post CEA-2010 SPL stats for comparison.

yeah...um, what he said! (I am still new to all the graphing )

You hit the nail right on the head. I wouldn't rush out and buy a 350 until I knew how it was differentiated with the 400 at least. John, it's all up to you to tell us. No pressure but with great knowledge comes great responsibility .

I am SO glad I can still play the dumbass card.