Since the cat is out of the bag on the new v4 subwoofers, I figured it would be a good idea to start an official v4 subwoofer thread where we can discuss these new products all in one place. I'll give a quick overview of what's new/changed/updated and then open the thread up to your questions/concerns/comments/etc.

So, what has changed?

ALL of the amplifiers are new. Although the amplifiers themselves appeared a few months ago in the v3 models, the full performance improvements and changes in analogue EQ (EP125/175/350) and DSP programming (EP500/600/800) have only now been implemented in the v4 models. All amplifiers now feature heavy-duty, panel mounted gold-plated input and output RCA jacks. No more 1/4" phono adapter or having to mix connections when daisy-chaining subs. The non-DSP models now only have RCA and speaker-level inputs, while full RCA and balanced XLR input and outputs, along with stereo speaker-level inputs can be found on the DSP models.

ALL of the woofers have been newly designed with higher linear excursion, higher power handling, and lower distortion. Higher power handling was required in order to make full use of the capability of the new amplifiers.

The non-DSP models now feature signature Axiom trapezoidal cabinets, revised bracing, and revised tuning/alignments. The EP125 and EP175 have grown somewhat in size and feature far greater low frequency headroom with longer ports for lower tuning. All of these models also utilize a newly designed pre-amp/EQ/limiter module that incorporates an "analogue biquad", essentially an extremely flexible parametric filter block that allows these models to now be nearly as linear as their DSP controlled big brothers. I would go so far as to say that, except in a head to head blind listening test, you would be hard pressed to tell the difference between an EP175v3 and an EP125v4! The EP350 has actually been reduced in size, and now features a triple vortex porting arrangement. I should also note that all of the non-DSP models utilize a unique bracing system that braces both the cabinet walls and the now much-longer port tubes.

For the DSP models, the EP500 has now also taken on the signature Axiom trapezoid cabinet shape and the EP600 has been reduced in height, falling between the heights of the EP500v4 and the EP800. The EP800 remains the same size (i.e. BIG!) but features revised bracing and a new, dual-chamber configuration. You can think of it as essentially two independent subwoofers in one cabinet. Now, the biggest change to the EP500 and EP600, that many of you have already noticed, is that all of the DSP subwoofers are now sealed, acoustic suspension designs. I'm sure that there will be many questions asking why we decided to go in this direction. The simple answer is distortion. At some point, ports have a tendency to make some noise, particularly with subsonic movie effects. There is also the issue that the woofer in a ported system becomes essentially unloaded below the tuning frequency of the ports. In order to EQ a ported subwoofer to be linear down to the lowest frequencies, we are asking a lot of the woofer in terms of excursion. With higher excursions, no matter how large the Xmax of the woofer, distortion increases. Sealed subwoofers have the benefit that they are constantly loaded by the pressure inside the cabinet. The required filtering is also more elegant and we are able to drive the woofer right up to the limits of the amplifier power available. The end result of all this technical talk is that, even though the EP500v4 has a smaller footprint and is a sealed box, it is capable of the same maximum output as the ported EP500v3 with less distortion.

To close, this project comprises an enormous R&D effort that took the better part of a year. We are very pleased with the results and hope that those of you that choose to buy or upgrade will be impressed by the results!

Cheers,

Andrew

I would like to see some pictures of the new models up on the pole.

Congratulations, Andrew. Well done.

Andrew.. I was thinking about getting 3 of the new amps, for my older EP-600's all of which are the ported enclosure design.. Will the new amps work ok with the older enclosures?

2 in 1 cabinet...

I've been wanting to upgrade from my EP350 V3 to an EP500 for a long time now. Looks like now might be a good time that the EP500 V4 is available. Got an extra 2 week payday in May. Might just have to spring for one.

My EP350 is Cinnamon Beech custom vinyl. Now the hard part of choosing which finish for the EP500. (Hmmm. Vermont Maple vinyl with Burnt Sienna grill)

Probably relocate the EP350 to the back of the room to utilize 2 sub woofers.

Sounds exciting!

Thanks for the update, Andrew!

Will the pricing be the same?

Why were sealed designs not considered until now? That was one of the main reasons why I did not go to Axiom for my sub woofers.

Now this i would love to see.


GET OUT!!
NO WAY THAT EVER HAPPENED!!
http://www.axiomaudio.com/boards/ubbthreads.php?ubb=showflat&Number=5356&site_id=1#import

Looks like you guys have been busy, Andrew!!

Can you tell me/us what advantage there is in going to a dual chambre design on the EP800? does it increase cabinet pressure thereby reducing distortion vs a shared chambre?

It will act as a co-located sub?
I just experimented with 2 pos subs and after stacking them the ceiling vibrates/resonates very very quickly (think blade of grass whistle).

Edit: The 800 would have been a beast before....

Probably need 2 amps to be equivellent to co-located.

Same here.

Great stuff, Andrew. I need more disposable income again!

My favourite little monster sub - EP400 - isn't mentioned in the updates.

Anything new with that model?

TAM

Hi Exlabdriver,

I can speak to the EP400 for you. It is going to get some further modifications later this year. For now it does have the new amp in it like all the other new models and it was already a sealed design.

Cool. Thanks, Ian.

My, you're up late, ha!

TAM

I think you've been abusing your ports chess. Mine never chuffed on Lord of the Rings.

Do tell.

Ian, with only a 2 db max room SPL difference between the EP400 and EP500, why is the EP400 only recommended for smaller rooms? Is there still a big difference in capability between the two models for larger spaces, particularly for music only?

Thanks for the detailed info Andrew. It sounds like a major shift in design philosophy and I can't wait to hear some reviews from the first board members to try them out.

"analogue biquad"

"I don't know what that it but it looks like a really good one of those." -- Manager in Dilbert

The new amp can be made to work, but it will not result in any improvement in performance. The DSP would simply be coded to be identical to what you have now.

Thanks Mark!

I believe the pricing will be increasing in line with the rest of v4 on April 23rd.

This is a difficult question for me to answer since I wasn't at Axiom when the original EP500 and EP600 were conceived. The EP400 and EP800 have, of course, always been sealed. Really my main focus in redesigning the subwoofer line was to identify areas where performance could be improved and then determine what would be required to achieve those improvements. New amplifier designs with far greater dynamic headroom and a new DSP engine then lead to the requirement for higher excursion woofers which then lead to the issue of port noise in the EP500 and EP600 at these new output levels. All of this together with the reduction in distortion by going sealed made the decision easy.

The advantage has to due with the distribution of air pressure inside the cabinet and the interaction of the two woofers with this common volume of air. The separate chambers do result in higher absolute back pressures on each woofer than with a shared volume by removing this interaction. This then leads to a reduction in distortion at high output levels.

Technically it is close to two co-located subwoofers. You can think of it as being nearly equivalent to two stacked EP500v4s. The amplifier in the EP800v4 uses two dedicated channels, so only the shared power supply keeps it from truly being two independent subwoofers in one enclosure.

Hi wschwartz,

The EP400 requires a lot more amp power to achieve the same output at 20 Hz compared to the EP500 and the added power has to start being added at a higher frequency. This means the EP500 will play louder lower than the EP400 even though the SPL achieved in the higher frequencies of each is not dramatically different. It is one of those things that falls in-between all the specs but matters in the real world. I think to achieve more clarity of the real world performance we should make the EP400 specs more conservative.

So, what is the advantage of a EP800 over two EP500 's
or is the EP800 made for those that want the high volumn and low frequencies, but do not have the space to place two EP500 up front ?

Hi Fred,

The revisions centre around lowering tuning frequencies to take advantage of the larger cabinets (EP125/175) and the improved parameters of the new woofers. To give you an idea of the changes, I have attached the natural frequency response (no EQ) of the EP125v3 (in blue) and the EP125v4 (in green). There is an improvement of 5dB between 25Hz and 40Hz with the new alignment, meaning less EQ is necessary, resulting in much greater low frequency headroom.

The EP800 will have the edge in terms of maximum output if the 2 EP500s are going to spaced far apart from one another. The EP800 is also able to be EQ'd to a lower cutoff frequency (12Hz vs. 18Hz for the EP500) for those that demand reproduction of ultra low-frequency information. In many cases two EP500s spaced apart will result in a more linear in-room response. It really comes down to your preferences and the space you have available.

I'm assuming the freq graph for the EP500 is only an estimate and not an actual measurement. It looks too even.

THIS is part of the reason why I love you, Ian.

And also part of the reason why some people periodically want to burn you at the stake.

Excellent Andrew. That's what I was looking for. Axiom's subs have been a weak spot in a lineup of exceptional value speakers.

If you have managed a similar change in response with a smaller footprint for the EP350 you will have a real winner on your hands.

Nope, it is absolutely a real measurement. The reason it looks so smooth is that it was measured as a near-field response inside the anechoic chamber. Because the EP500v4 is a sealed sub, the near-field response is equivalent to the 4pi response once the SPL is corrected for 1M and the radiating area of the driver is taken into account. Just for fun these curves were compared to the original pole measurements for the v4 subs and they correlate perfectly. The new DSP algorithm for response correction also helps!

Thanks Andrew. I was hoping that to be the case, but assumed it wasn't. I also noticed the price increase is to be on April 23, as you had mentioned. I was going to order on May 16, but will order tomorrow instead to take advantage of the lower price. I hope this will be worth moving my bill paying around in order to take advantage of missing the price increase.

Andrew, did you/Ian consider any opposed driver designs? not sure if I recall it was on the table or not about a year or so ago.

Ordered the EP500 v4 using the Trade-Up program. I almost forgot about that. Saved me a lot of money. Thanks Brent.

I was hoping for an in-wall LFR subwoofer announcement.

Awwwww.....crap! I was quite intent on keeping my V2 and V3 stuff.

So how do the V4 500's compare to the V2's, performance wise? I have two EP500's in my room. What would a reasonable expectation be if I were to upgrade to the V4's, with respect to sound quality? My room is 12X18X9. M60s and a VP160 with three sets of QS-8's.

I have a ep500 v4 on layaway.. getting my new inverted vp 180hp v4 Tuesday to replace the vp 180 v3 ... feels like xmas!!!

My order for EP500 v4 just went through this morning. Vermont Maple with Burnt Sienna grill. 10 days and counting.

This is an upgrade from an EP350 V3, Cinnamon Beach with black grill. I purchased 4 years ago. Good price through the Trade Up program.

I come real close to ordering an SVS-PC12 Plus instead. But the Trade Up program sealed the deal for Axiom.

Considering recent conversations was "sealed the deal" an intentional pun?

As in Sealed vs Ported? Nah. Just a coincidence.

Are there any reviews using the new EP500 v4 speaker yet?

Looks like that will be up to you, Brian. Good to see that you held off until the V4s.

Got a 500 v4 coming also but the only comparison I can do is with my ksw-15.. so it's either WOW or disappointment

I just ordered two 500's, along with some M80's and a VP160.

Ha! Custom finish?

Well of course. ... waiting for some different walnut samples to choose a stain color.

I love the wood choice there. Walnut is very nice. I've got a black walnut counter in the wine cellar. Damn dense wood. Took three saw blades to cut a 4 foot length.

So, some new EP500s sealed enclosures?
I look forward to hearing about what you hear.
I'm still pondering a sub replacement myself.
Never been truly happy with the EP350 (the old EP350 that is).

Your EP350 is like a v1 or v2, right? The v3 is much bigger and more powerful.

I've been very happy with my EP350 v3. Lots of power and bass. But that was my first major subwoofer purchase. I haven't had a speaker upgrade in close to 2 years and now craving something new. I feel the bass is probably my weakest point and now really wanting an upgrade now that the new models are available.

Can't wait to watch the new Tron movie with the 500. This is the movie that gave the 350 the biggest workout.

My QS8s are walnut. Very pretty. I built a couple book cases out of the stuff too. I just can't make up my mind which stain to go with. Looking forward to testing the sealed versions. Will report back.

Congratulations on the new subs, guys. Can't wait to hear your impressions of them.

Greetings everyone - new forum member, here. I have been a proud owner of Axiom products for about a year, now, and am absolutely thrilled. I have posted some pictures of my room in the Gallery. I have a pair of m22s and EP400s right now (2.2 setup) with the ADA1000. Such a fantastic setup!

I just pulled the trigger on two EP500v4 units (trading up from the EP400s). And a pair of new tweeters for my m22s. I love the 400s but am hoping that I will be able to play the 500s a bit louder in my room (medium sized room). I am looking forward to hearing how the 500s compare.

To Andrew Welker and the others on the Axiom Design team, I wanted to say that I am so impressed by everything I have purchased from Axiom. Everything performs so well. I couldn't be happier !

Cheers!
Rob

Thanks for the heads up and glad to hear your trading up..lol

Welcome, Rob!

Thanks brsaw and tomtuttle!

I wanted to give everyone an update. I have successfully transitioned from my two EP400v3 subs to my new EP500v4s. I was happy before the upgrade, and I'm still very happy now.

First off, I have to say that after doing the upgrade, I have all the more appreciation for the output that the EP400s are capable of. Anyone who requires a smaller sub due to space considerations would would be very happy with these !

As you might guess, the EP500v4s are capable of higher output without having to "work" as hard, as evidenced by less dramatic cone movement. Subjectively, I am fairly certain that I am hearing less compression, and deeper lows at louder playback levels with the 500s as well (for various possible reasons). To be fair, this was also a v3 compared to a v4 and so the new V4 amps may also be contributing to some of the differences I am hearing.

If you are trying to decide whether to go with the 400 vs the 500, I can tell you honestly from my own experience - having used the 400 regularly for critical listening for over a year - that the 400 is a fantastic sub that sounds much bigger and deeper than you would expect an 8" sub to sound. Whereas you could go with the 500 if you have the room for it, and require maximum loudness.

Cheers!
Rob

Bumping an older thread, sorry.

Earlier in this thread there was some discussion of scheduled updates to the EP400 later in 2014. Did that occur, or on track, or mothballed?

(I've been wanting to trade my EP500 v3 towards two EP400, but would want to know if there are impending revisions)

The plan for the EP400 is to change the shape from rectangular to the same look as the rest of our speakers. Beyond this we are going to have the current standalone version plus a paired version. The paired version would have an extra amp channel in the one EP400s with a binding post output to run a speaker wire to the second EP400. This would result in effectively having a dual 8” subwoofer but with the added advantages of being able to strategically place them in the room and the size of each being half that of a dual subwoofer.

Ian, would this (how would it) act differently than a daisy chained pair?

It is very similar to a daisy chained pair. The advantage is in the cost savings of sharing a single power supply and DSP board.

That sounds interesting. I look forward to hearing more as they are released.

This sounds like the perfect way to do EP400s.

Very interesting indeed. Would the new, familial-shaped cabinet be smaller than current for both the slave/master units? And is there a ballpark estimate on availability this year?

The size will be very close to the current dimensions for both the master and the slave. We will have them ready this spring.

With my pair of V3s, I kinda like my 500 Watts per side especially since they are being driven by only 35W/Ch.

Furthermore, I have true 2 Channel (stereo) for music only as I drive each one separately from the L & R Speaker Outputs of my Integrated Tube Amp.

The new version looks like a good idea though....

TAM

What do you mean by rest of our speakers? are you talking about subs or speakers like the M80? I am wondering if you could give us an idea as to what dimensions you are envisioning and if they will still give that wonderful 18hz deep bass? or lower?

I imagine it will be close to the same volume but with the trapezoidal shape.