Axiom Audio EP500 VS SVS PB12-Plus/2

[Manic Miner]

isn't 1m roughly equal to 3.2'. So, a 10m2 room is like 32'x32', and I consider that very large. I'm guessing you got your conversion backwords.

I would be quiet unhappy with a Plus/2 in a 30x30 room, especailly if it wasn't sealed.

1 meter is 3.282 feet. So 10m squared is about 107.5 square feet, Imelda Marcos could not fit 5% of her shoe collection in there

 

[Buckeyefan 1]

Jakeman,

Thanks for the graph. What I'm reading there is the Axiom is a bit stronger (spl) in the 18-23Hz region, then dominates between 40-100Hz (linearity). The Plus/2 may be the chioce for those looking for the deepest transient bass, and those who crossover capable towers at 40Hz (also assuming they have the room to fit the massive end table).

In your opinion, would SVS benefit by going to a DSP controlled digital amp, or is the issue the large cabinet, dual driver configuration?

 

[Manic Miner]

Those measurements jakeman are showing were done by Axiom themselves, and they have allready been found to 'not reflect real world performance' to say it in the nicest way possible

 

[Manic Miner]

Jakeman,

Thanks for the graph. What I'm reading there is the Axiom is a bit stronger (spl) in the 18-23Hz region,

That alone shows that the graph is worth nada. The EP500 has a tuning frequency of 25hz, a smaller box and a driver with shorter stroke. For it to be able to out SPL the Ultra in the 18-23hz region it would have to be a magic subwoofer, nothing less.

 

[Buckeyefan 1]

That alone shows that the graph is worth nada. The EP500 has a tuning frequency of 25hz, a smaller box and a driver with shorter stroke. For it to be able to out SPL the Ultra in the 18-23hz region it would have to be a magic subwoofer, nothing less.

The graph is worth nada? That reminds me of that movie rental commercial where the kid says "man this place has nada," and the clerk says "we have nada three."

 

[jakeman]

HI Buckeye,

That's a good question. I have both the Ultra and the 500 which have their strengths and weakenesses. Implementing a DSP controlled solution would benefit any sub IMO but there is a great deal of R & D associated with getting the electronics, amp and driver acting in harmony. That means its expensive so for SVS, or HSU for that matter, to feature this new technology would mean a higher price point which is likely the bigger issue. I know Axiom spent 2 years on development before introducing the EP line so its not as easy as just inserting a chip and now I see Mark Seaton is rumoured to be implementing a DSP solution with his new sub.

The SVS designers are very good at their craft and they do make a competitive line of products. I'm not presumptious enough to suggest I understand all their design tradeoffs but it seems to me that they like to emphasize extension, SPL and low THD which you get with bigger enclosures and dual high excursion drivers. What you also get IMO are significantly higher other distortion artifacts like dynamic and IM distortion which are tough to measure but audably noticeable . Their choice of drivers also contribute to their relative lack of FR linearity. So its a mixed bag.

For HT their products are pretty good though I find the upper bass lagging I really like the infrasonic stuff. If you listen to HT exclusively though they are a good choice. For music I usually shut off the Ultra and listen through the 500 when I use a sub. I listen to alot of music and I always smurk when someone calls the SVS subs musical-- because their lack of linearity and smearing compromise music reproduction. Interestingly 5 of the 6 other listeners at Craigs GTG heard it that way as well so its not like I have golden ears.

 

[jakeman]

That alone shows that the graph is worth nada. The EP500 has a tuning frequency of 25hz, a smaller box and a driver with shorter stroke. For it to be able to out SPL the Ultra in the 18-23hz region it would have to be a magic subwoofer, nothing less.

The 500/600 tuning frequency is 21-22Hz same as the Ultra which is why they work reasonably well together.

 

[Manic Miner]

For graphs of the Ultras FR see this

http://www.avforums.com/forums/showthread.php?t=247703

http://www.avtalk.co.uk/forum/index.php?t=msg&th=14971&start=0&rid=0&SQ=0

Consider the facts, and the sources.

Here are the graphs for the PB and the PC Ultra from the two tests

A bit different from Axioms measurments?

And while you already are browsing Ilkkas measurements please take a look at the GD, and decay data for the Ultra in 12hz tune, I wonder if that is why I prefer my Plus tuned to 12hz for music.

 

[jakeman]

Not worth debating for the nth time MM but the LMS software is much more advanced. In any event the overall shape of the curves look similar despite the low resolution RTA smoothing. Its just more info for the OP.

 

[Buckeye_Nut]

My 2 cents.....

I see it like this. Both are quality subwoofers, and I'll compare them to car engines......

The Axiom has a quality V-6 under the hood, and the SVS has an equal quality bigblock V-8 motor. Both are similar quality engines that serve their intended use well, but the big block has more horepower and has greater capability. Splitting hairs over whether the V-6 is a better engine than a V-8 is comparing apples to oranges.

 

[---k---]

1 meter is 3.282 feet. So 10m squared is about 107.5 square feet, Imelda Marcos could not fit 5% of her shoe collection in there

Oops my bad. I read that, and thought that you were using short hand to imply 10mx10m.

A 107ft2 room - talk about comfy!

 

[bobgpsr]

I will post this graph comparing the 500 to the Ultra to assist the OP seeing how its been discussed extensively already.

Are not those the 17 ft on a pole tests with the meas mike at 1 meter (which did not allow the SVS ports to correctly sum their contributions)? The uneven below 20 Hz peaks would seem to come from odd ground reflections. I'll bet a proper GP test would not show such an uneven response. That plot from last fall caused intense controversy in the AVS forum. Several highly respected experts pointed out problems with those plots.

 

[craigsub]

Bobgpsr, There is nothing wrong with having a GP session compared to another GP session. In fact, it would be interesting to see Frequency Response graphs of all these subwoofers without the 1/6th octave smoothing applied. Do you know of any ?

However, this worrying about reflections coming from the ground, even at 17 feet, is unfounded. Noone is worried about the response below 20 Hz in this graph. Both subwoofers were tested under identical conditions in the graoh jakeman posted. Sure, I would prefer to see a measurement from 70 feet off the ground, but can you specifically point to the areas of the response curves that sound travelling 10 meters will affect the measured response response from one meter ?

 

[bobgpsr]

but can you specifically point to the areas of the response curves that sound travelling 10 meters will affect the measured response response from one meter ?

The 17 ft distance is not involved with the problem of the 1 meter mike distance not giving the SVS ports the ability to correctly sum their contribution. Mark Seaton opined on the problems of getting a proper mike distance from the sub to get proper blending of the ports & the driver contributions for overall sound output measurements.

So yes, two different issues:

1. Meas mike may be too close to allow SVS ports to sum correctly.

2. Uneven response due to odd ground reflections (if you don't care about below 20 Hz then fine --- but some of us want to see a smooth rolloff at the proper dB/octave slope for a bass reflex design).

 

[ssabripo]

The 17 ft distance is not involved with the problem of the 1 meter mike distance not giving the SVS ports the ability to correctly sum their contribution. Mark Seaton opined on the problems of getting a proper mike distance from the sub to get proper blending of the ports & the driver contributions for overall sound output measurements.

So yes, two different issues:

1. Meas mike may be too close to allow SVS ports to sum correctly.

2. Uneven response due to odd ground reflections (if you don't care about below 20 Hz then fine --- but some of us want to see a smooth rolloff at the proper dB/octave slope for a bass reflex design).

Bob..give it a rest, this will only lead to the problems seen over at AVS. As you noted, Mark Seaton, Ed Mullen, and many many others already talked about the problems and the innaccuracies of the Axiom graphs. John holds tight to this graph as "bible", so trying to come to a technical agreement is near impossible. The independent graphs from AVforums/Finish shootout/Ed Mullen are much more meaningful to most of us.

No worries there....I think you are seeing what most of us see.

 

[craigsub]

The 17 ft distance is not involved with the problem of the 1 meter mike distance not giving the SVS ports the ability to correctly sum their contribution. Mark Seaton opined on the problems of getting a proper mike distance from the sub to get proper blending of the ports & the driver contributions for overall sound output measurements.

So yes, two different issues:

1. Meas mike may be too close to allow SVS ports to sum correctly.

2. Uneven response due to odd ground reflections (if you don't care about below 20 Hz then fine --- but some of us want to see a smooth rolloff at the proper dB/octave slope for a bass reflex design).

Bob, This is where things always get testy. I said noone was worried about the below 20 Hz response curve. That is not the same as not caring about below 20 Hz response. If you wish to be involved in a conversation, mis-quoting people is not a good way to start.

The reason people need not be concerned with the response curve below 20 Hz is the Axiom has a sharp filter below 20 Hz, and the SVS had its 20 Hz filter switched on. There were also measurements taken with the Ultra in its 16 and 12 Hz tuning. In those, the curve below 20 Hz IS important.

I saw Mark Seaton's posts, and he was theorizing. I have seen the response curve from two meters, and other than being 6 dB lower, it is identical. I posted graphs on this months ago.

There are no published 1/24th, unsmoothed FR curves - well, I have not seen any.

And at ten meters, the SPL abberations would be down about 20 dB from the fundamental, less whatever absorbtion the ground had. That is not going to be much of a factor.

 

[craigsub]

Bob..give it a rest, this will only lead to the problems seen over at AVS. As you noted, Mark Seaton, Ed Mullen, and many many others already talked about the problems and the innaccuracies of the Axiom graphs. John holds tight to this graph as "bible", so trying to come to a technical agreement is near impossible. The independent graphs from AVforums/Finish shootout/Ed Mullen are much more meaningful to most of us.

No worries there....I think you are seeing what most of us see.

Sherv, If you look at the Finnish shootout, you will see the Axiom's curve was also much smoother there than in the LMS curves, just was the case with the SVS. A 1/24th octave smoothed to 1/6th octave will always look smoother than a raw LMS curve.

As long as one is comparing within the same graphing methodology, we have an even playing field. Look at the 25 Hz output on the SVS on both curves, then at the 80 Hz response ... both are down about 8-10 dB from the 25 Hz SPL.

 

[jakeman]

Are not those the 17 ft on a pole tests with the meas mike at 1 meter (which did not allow the SVS ports to correctly sum their contributions)? The uneven below 20 Hz peaks would seem to come from odd ground reflections. I'll bet a proper GP test would not show such an uneven response. That plot from last fall caused intense controversy in the AVS forum. Several highly respected experts pointed out problems with those plots.

The graph you are referring to is the comparison of GP and 4pi curves of the Ultra which I had done and posted at AVS for discussion purposes. I've seen problems with several of the SVS graphs posted which is why I went to get my own done. It's not my intention to revisit all those controversies, suffice it to say these were done pursuant to my instructions with much more sophisticated hardware and LMS software using both GP and 4pi testing techniques. I posted these to give the OP the benefit of further information in light of several less accurate and precise graphs that were being discussed.

Stepping back from the graphs, the main message for the OP is in the lack of linearity of the Ultra, the better extension of the Ultra, the better upper bass and flat response of the 500, and the superior sound quality of the 500.

 

[ssabripo]

Sherv, If you look at the Finnish shootout, you will see the Axiom's curve was also much smoother there than in the LMS curves, just was the case with the SVS. A 1/24th octave smoothed to 1/6th octave will always look smoother than a raw LMS curve.

As long as one is comparing within the same graphing methodology, we have an even playing field. Look at the 25 Hz output on the SVS on both curves, then at the 80 Hz response ... both are down about 8-10 dB from the 25 Hz SPL.

Craig....you know where I stand, and thus I respectfully remind you that we just disagree in the methodology and accuracy of the graphs from Axiom John's fishing trip and his stance on LMS vs RTA, 4pi vs 2Pi, IM distortion vs THD, etc, etc, is on one side of the spectrum while many of us (including folks like the Ed Mullens and Mark Seatons of the world) are on the other. But from a graph perspective, the one from Axiom is useless to me, and thus, we can post the ones from AVforums/finish shootout/Mullen and start to analyze and discuss from there........that axiom graph means nothing to me, Sorry

But I'm all ears man...lets talk and learn ....just let me know if I need to stop by costco for some popcorn

ps- how did I know such proposterous statement as "the main message for the OP is in the lack of linearity of the Ultra, the better extension of the Ultra, the better upper bass and flat response of the 500, and the superior sound quality of the 500." was gonna come at some point?
"lack of linearity"? according to who?
"superior sound quality"? wow, I don't think even the GTG participants can make a blank general statement like that. It sounded better at the GTG and under those room acoustics and setup. It has easily been agreed that a complete reverse agreement could have been found at a different GTG. Never once have I heard ANY of the GTG guys, including Craig, to say that it is now a known fact that one has "superior sound quality" over the other one in all scenarios. *sigh*

anyways, I guess in the interest of keeping the thread in a positive spin and moving forward in learning mode, I'll leave it be.

 

[craigsub]

Craig....you know where I stand, and thus I respectfully remind you that we just disagree in the methodology and accuracy of the graphs from Axiom John's fishing trip and his stance on LMS vs RTA, 4pi vs 2Pi, IM distortion vs THD, etc, etc, is on one side of the spectrum while many of us (including folks like the Ed Mullens and Mark Seatons of the world) are on the other. But from a graph perspective, the one from Axiom is useless to me, and thus, we can post the ones from AVforums/finish shootout/Mullen and start to analyze and discuss from there........that axiom graph means nothing to me, Sorry

But I'm all ears man...lets talk and learn ....just let me know if I need to stop by costco for some popcorn

Sherv - Let me try this with some humor mixed in. Taking any number of subwoofers and measuring them in a 4Pi setting with LMS will have ALL of them looking like crap, when compared to a smoothed graph done 2 Pi.

Yes, the SVS looks worse when done 4 Pi. So would my Velodyne DD-18, and your DIY project. The Axiom looks crappier there, too.

However, if you want to see REALLY crappy graphs - run some unsmoothed graphs of a subwoofer in any room.

I will be posting some 10 to 50 Hz in-room graphs this weekend. I top out at 50 Hz because I crossover my system at 50 Hz.

Anyway, the LMS curve done 4Pi is a total anal exam of what the subwoofer is actually producing, with no interference from any other source. Why that fact (and it is fact, regardless what anyone trying to argue with it says) upsets people is beyond me.

Keep in mind, I personally do GP measurements, but stating that 4Pi is more accurate than what I personally do does not seem to offend my masculinity ...