SHOOTOUT! Epik Empire vs HSU VTF-15H vs CHT CS18.1 vs Rythmik FV15 vs eD A7s-450 - Page 14

Agree that you guys said the same thing, well sort of, in your review preface (perhaps elsewhere as well?):


Perhaps, in hindsight, you could've reinforced it further, something like this made-up quote:


In the end, I don't think anyone is necessarily questioning bossobass's technical chops - simply his method of delivery, which at times can rub people the wrong way.

In the end, however, bosso, pbc, craig john, penngray, MKTheater, et. al., make excellent points - rooted in their technical knowledge and expertise with the subject matter, which is quite extensive.

The shootout reviews were great, and the post-shootout dialogue has (mostly) been as well... all of it educational. Thanks again.

Actually, the majority of people are going to use Audyssey or some sort of AVR equipped EQ device which, by its very nature will try to flatten the response. So maybe not so ridiculous. It may have been an interesting exercise to have at least run Audyssey from the LP (using a tripod) each time before starting the review of the sub, and then posting the response.

Further, we're not saying EQ them flat. We're saying at least try to get the subs a) level to each other and b) their frequency responses as close as close as possible so that if you are going to make comments on SQ about one sub versus another you'll at least have attempted to remove your own "room" from the equation as much as possible.

What's really unfortunate is that what you're not realizing is that your conclusions about the SQ of subs are entirely meaningless not only to others and their rooms, but in fact they are meaningless in your own room. Because what you're really commenting on for the most part are the obvious level differences across frequencies (which you could have eliminated to some extent with a little extra work) versus how one sub compares to another.

Maybe people find that to be "belittling", or "condescending", or whatever. Unfortunately it's the truth as Penngray put in his usual eloquent way, and Bosso tried to explain in his condescending "holier than though" "belittling" manner, or MK hinted towards, or Craig John, or Chu, or etc. etc. etc..

Anyhow, I know I'll be sorely missed (in particular by my new best friend Jack), but I won't post in your thread anymore.

pbc I appreciate your last post. nicely worded, clear and polite. That's the kind of post we need here, and hopefully this thread will get back to that.

I have no problems if you disagree with our methods. The point I guess I'm not making too clear is that we DO understand what bosso, penn and others are saying. We knew before we even posted that group would disagree with our methods. However, we talked about it a LOT, and put ourselves in the shoes of someone just starting out. We always came back to the notion that testing the subs as they come makes our results more relevant than to do it like yourself and other more experienced enthusiasts would.

Please be assured, when we review subs that we feel most people will take the time to eQ and room correct, we will certainly do that. And we might even ask for your help if we get stuck. But for the purposes of this shootout, we did it the way we did it and by the response it seems a lot of people did find it useful.

I offer my virtual hand to you in that perhaps we have an understanding...

In-room subwoofer response is dominated by the room.

Let me give you a demonstration of that concept:

Here is the nearfield response of one of my Submersives, with an 80 Hz crossover set:

(The two curves represent the two DSP programs available in the amp)

Here is the in-room response of one Submersive on the left wall at 1/5 of the long dimension of the room:


Here is another Submersive on the front wall at 1/3 of the front wall dimension out from the right corner:


And here is the 3rd Submersive on the right rear at 2/3 of the long dimension:


Obviously, all 3 of those placements will sound different. If you were to take a bunch of different subwoofers and place them in each of those spots, and then rank them on "sound quality", you would end up with 3 different sets of rankings, 3 different sets of listening impressions, and none of them would have any bearing on what those subs would sound like in any other room or placement.

As I said before, the room dominates the in-room measured response. If you want to compare subs, you need to remove the room from the comparison. That is the only way to say anything valid in terms of comparisons.

There are two ways to "remove the room from the equation." First, you can take the sub out of the room. There is one company that actually takes their subs outside, hoists them up on a crane and measures them in the air:
http://www.axiomaudio.com/research/S...ringTower.html
They measure at 360 degrees around the sub and combine the measurements to form a composite of the sub's output. This is the equivocal "gold standard" for measuring subs.

Short of that, other people do this with "outdoor, groundplane" measurements, (see Illka's measurements previously linked to in this thread.) Outdoor GP measurements are not perfect, but they are definitely better thanin-room, uncorrected measurements if you want to compare output, extension, distortion, compression, etc.

Second, if you can't take the sub out of the room, you can "correct" for the room. You can do this with EQ. How effective you can be will depend on the extent of the acoustic issues and the resolution of the EQ.

If you choose to do neither of these, then all you comment on is... your room. You can't say anything "useful" to anyone else about what those subs will sound like in anyone else's room. And when I use the term "useful", I don't mean that what you heard in your rooms was incorrect. I mean that is has no validity outside your own room.

I hope you don't think I'm belittling you here as that is not my intention. If you guys are planning to do another shootout of higher priced subs, it would behoove you to make the effort to do it in a way that removes as much criticism as possible. I know you've stated that most people will just plug and play their subwoofers, but as you go upscale in price, more people will be willing to make the effort at optimizing their investment.

Craig

Edit: Sorry, it took me a while to compose this post, and I see you've addressed some of this already.

First of all, I want to commend you and Madeel on taking the time to do this shoot out. You guys did an amazing job and I hope that the bickering that has occurred in the past couple of pages does not quell your passion for this hobby.

Six years ago when I first entered this hobby, I had little knowledge about anything AV. Though I've learned a lot by lurking on various AV boards, my level of expertise is nowhere near the level of some of the other members. The most important thing that I have learned over the years is that the overriding factor of subwoofer sound quality is how it interacts with the room.

This was confirmed by fooling around and experimenting with my SMS-1 and multiple subwoofers. I've realized that altering the frequency response curve had more of an impact on sound quality than the subwoofer itself. Because every subwoofer has different native frequency response curves, each subwoofer will behave differently in different rooms. What you perceive in your room for each subwoofer may not be what others perceive in their own room.

For example, in your room, your frequency response curve looked like this:


In a different room, that frequency response curve will look different. For example, this is a frequency response of the VTF-15 (both ports open) in a different room. This person was underwhelmed with the VTF-15 and felt that it lacked the "chest thump" that you probably felt. This is because he has a 10-15dB dip between 50-100Hz.



I would suspect that a different subwoofer may have "won" from a subjective standpoint in his room. To a certain extent, EQing each subwoofer flat would takes this variability out of the equation. I would argue that it would be make your subjective observations a little more generalizable to all rooms.

Just my two cents. Thanks for listening and I can't wait for your next shoot out.

EDIT: This post also took me awhile to write, I didn't realize Craig John beat me to the punch. As usual, he did a much better job explaining this than I did. Sorry for being redundant.

^^^^
I like more this other one
http://www.avsforum.com/avs-vb/attac...9&d=1292520686

But, anyway... room is the king.

There is another much simpler way of minimizing the room effect on a sub's response. That would be the close-mic'd response measurement. Almost anyone can do this indoors and get a pretty good approximation of the sub's natural response with minimal interference from the room. The mic would need to be no more than a couple of inches from the cone or close as possible to both the cone and the ports. A very low level signal is then used for sweeps.

Not redundant at all! More verification of the principals is a good thing.

To pbc's point about using Audyssey, I agree that room correction systems are becoming more widely accepted and beneficial. I have recently upgraded to Audyssey XT32, and the results have transformed the sound of my system.

Here is the combined response of my 3 Submersives *without* Audyssey:


And here is the combined result *with* Audyssey XT32:


The difference in Sound Quality between these two results is astonishing. And once you get the magnitude response this flat, it's easier and more valid to do level matching.

Craig

Yes, I showed an example of that in the first graph in my post above. Your description is exactly how I did it.

Craig

Wow, so you manage to have 3 Subs with XT32? I though it was only able to handle 2. Nice!

In those graphs, I had all 3 subs on one output. I was not using the SubEQ HT feature, which sets separate levels and distances for each sub. I have since set the system up with the 2 more distant subs on one output and the closest sub on the other output. The results are indistinguishable.

Craig

^^ok!

I just found a link on my pen drive and want it to share it here for the benefits of others... This just show a guy there playing with sub placement in his room and Audyssey... Sub EQ benefit any sub!

> Here <</a> Post #22 is quite interesting... because of....THE ROOM!!!
.

This post maybe helpful as well. (VTF 15)

Nice curve. Was dying to get XT32 before, but now i'm even hungrier.

I don't think we're covering any new ground here... I've already stated that after this quote and this thread , my experiences with Bossobass' comments is to take them at face value. You believe there's significantly more to the comment than it states. I can't argue with what you believe in this case since we both can't read his mind. I can only state my opinion.

I was thinking the same thing.... Then I thought to myself "I can't believe I'm saying this about subwoofer FR and not a woman."

craig john, out of curiosity, what software are you using to take the measurements?

I like the way the review was done, I think very few normal people use SPL meters.
Not every AVR EQs the subwoofer (Pioneer) and there have been long discussions about Audessy messing up subs to the point of causing amp failures (ED thread).
All the subs were put in the same room at the same location and the FR graphs reflect this so its apples to apples.
The method of level / gain matching was described.
Tones were run and graphs were made.
The sealed subs roll off as expected (twin drivers in Epik reacted differently to the room).
The ported subs are both tuned to 25Hz and the Hsu falls off faster than the Rythmik but both at more than 10dB down at 20Hz.
Good review and a data point worth taking note of.

When I posted the "make love" thing... I was wondering if people here will be ok with that.... but you see... I was not far from reality

just kidding jhan1000.... take care

xtz Room Analyzer
http://www.xtz.se/uk/products/mearur.../room-analyzer

The "official" thread:
http://www.avsforum.com/avs-vb/showthread.php?t=1264522

Craig

And, FWIW, my view is you are reading things into bosso's statement that are not there. I'm happy to agree to disagree. But I'd hate to read any post or review or article that included in every sentence every caveat, obvservation and statement previously made that is relevant to the statemnt. Every sentence would be a page long

In his room, all subwoofers tested in that particular farfield location would exhibit a dip in the mid-bass response (assuming that they have a reasonably flat mid-bass response to begin with). I'm sure if he places the subwoofer in the nearfield location in his room, it will sound much better!

Sincerely,

I don't think anyone said EQing the subs flat is the only way to test them. I believe the "notion" was that it's the only way to test them fairly.


EDIT:

I see that pbc, craig john and others already beat me to it. These guys really know their stuff. All great info for your next shootout.

Btw, I still enjoyed your shootout, warts and all. It made for some great reading and eye candy.....minus all that underwear madness...

but would probably lose a bunch on the low end, right?

In that "other thread", you called out Bosso for:


Now, in this thread, when he "expressed his findings to the masses," you're calling him out for being a "bully" and being pompous, arrogant, condescending and belittling. What exactly do you want from him?

Craig

Awesome! Here I thought we had moved on... Good to see this subject isn't going anywhere.

I called out bosso in the other thread for failing to use his knowledge to help evaluate subs for the masses (I'm more than willing to elaborate rather than hide btw). He's not doing that here either. He's criticizing other reviews. There's something constructive in the intent, but it's a complete failure in execution when the original reviewer comes away baffled that the constructive criticism is laced with belittling comments and egotistical remarks.

What do I want from him? What started out as a request to substantiate the basically undefendable statements that he's trying to pass off as fact has now evolved into a "how far will the Bosso Apologists go" to defend those statements. Watching these apologists abandon logic, not even consider the hypothisis that Bosso's remarks true intent was to devalue the review helps me gather data on who's really here to get to the real answers, and who is here to be popular.

this is supposed to be a hobby for fun, right? Right?

Ok, you convinced me... I'm officially done with your convoluted logic and misplaced emotion. See ya..

Craig

I get that you are not a big fan of the way Bossobass comes across.... Just so that I am clear, do you find the following statement to be true:

"Unless pains are taken to flatten the FR at the LP (and against a wall is normally not a preferred LP for that to happen), SQ differences that exist in the subs will be absolutely swamped by frequency response non-linearity, making subjective comments all but impossible, regardless of who the listener may be."

The VTF-15 was just reviewed by Sound And Vision, very interesting results. Check it out if you're done arguing! http://www.soundandvisionmag.com/aud...-15h-subwoofer