OK...with all that aside, I was wondering if there was one test that would be possible for you to do. Can you measure how fast the driver starts and stops when it is given a signal?I haven't seen a test measure for this, unless it was called something else and I missed it. But I really think this is important. I'm thinking that both subs will measure a very similar frequency sweep at 80-90 dbs whether in room or anechoic at less than 10% THD. But I also think they will sound a little different on certain music within the same db range. THis, I think will be more of a speaker differnce (or the materials that make up the speaker, than amp.
Another consideration is that each amp may have an eq boost, albeit slight, to achieve it's frequency response goal. How much of boost, if any, that drains power at high spl would be interesting to note to some (me). I would like to see you measure output while playing your DVD's (in your PB2+ review) to see what output you get. Although your ground THD test may reveal this as a factor if one sub distorts at say 30 Hz but can play 3 or more dbs louder without reaching THD at 30 Hz.
you have the stones to turn around and criticize my proposal of instrumented testing?Did I criticize your proposal of instrumented testing? What exactly did I say that you interpreted this way?
The problem that I have with your approach has nothing to do with the instrumented testing that you propose. In fact, with my limited knowledge in this area, it seems like a pretty good approach.
However, I do have major problems with the overall scientific methodology and this is why I made the statements that I did.
There are other statements made that I could address. However, I think these are sufficient to address the major issues.
Now, for the meat of what I want to say.
Ed has stated some valid criticisms of me about getting off the sidelines and contributing to this effort. I will be glad to do this (as I have stated before) but only if the concerns that I see are addressed.
First of all, I consider myself to be an expert in a number of areas. However, that expertise does not extend to subwoofers or testing audio equipment. I will be the first to admit that there are many people, including the people contributing to this e-mail thread, that possess far greater knowledge than I do in this arena. Therefore, I will not presume to judge the technical aspect of this analysis (although I am a very technical guy in other areas).
One of the areas I do consider myself to be somewhat of an expert in is in how to perform scientific studies. The expertise that I possess in this area is what lead me to the statements that I made earlier.
For example, one of the areas that has (at least partially)invalidated virtually every professional audio review I've read (and, at this point in time, I've read a lot) is the question of whether the review was "unbiased". I know of only two ways to guarantee this (there may be others): (1) have the analysis performed by a reputable independent laboratory or (2) engage the full support of all parties involved and get their sign-off on the fairness of the analysis at every stage. The first of these options is probably not viable due to cost. Therefore, I think the only option that is viable is to get complete engagement of the affected parties.
A general invitation to the masses isn't going to cut it.
I have a number of concerns in other areas having to do with the methodology being followed, which I will be glad to express. However, as this point in time, I am still smarting from the attacks on my personal character.
Therefore, I think the only option that is viable is to get complete engagement of the affected parties.What if the affected parites (I'm assuming you mean HSU and SVS) can only agree on one type of test? And what if the test is only in room 6 feet from the sub at 85 dbs on 1/3 octave test tones? That won't tell you much. I'd rather see a battery of test performed and formulate my own conclusions based on the data presented.
Ed's review will likely rival just about any subwoofer review I've seen lately. The most recent professional PB2+ reviews have little to no objective measures, not even a simply frequency sweep plot. I have yet to find one subwoofer review where I thought the holy grail of subwoofer review techniques were employed. If enough reviews of a given subwoofer are performed some consistencies about the sub will surface.
In the end, if a reviewer declares a particular sub the winner you don't have to agree. As long as the test shows enough objective measures, you may weigh a certain criteria more or less important than the reviewer did and therefore come to a different conclusion.
My comments were not intended to be mean-spirited and, if they came across that way, I apologize.Thank you, and I also apologize. Let's bury the hatchet.
As far as where this particular test goes - I don't care anymore. It has quickly turned into a lose-lose proposition for all involved, and I'm dropping the offer. I've got better things to do.
I'll test my own PB2+ with my equipment and possibly offer that up as an addendum to my original PB2+ review.
If I ever upgrade to a better SVS, I'll do another review with the new test methods.
And if I can get my hands on a local HSU sub, I'll put it through the paces and post that data too.
I'll test my own PB2+ with my equipment and possibly offer that up as an addendum to my original PB2+ review.I'll be looking forward to this. I know you have a better mic than the Rat Shack but I would be interested in seeing you plot the 1/12 octaves using the rat shack meter as compared to the reading with your mic. Just to see how accurate the rat shack really is.
Since no one else offered up any other test methods, your statement can easily be inferred as a direct attack on my character.What?!!! A direct attack on your character? Give me a break.
Calling someone a hypocrite and then saying they deserved it is attacking one's character. Challenging one's testing method, which, as I explained, is not even what I was doing, is in no way an attack on one's character (at worst, it's an attack on the approach they are advocating).
Equivalencing your actions with my actions simply infuriates me.
What I did, challenge your methodology, and what you did, calling me a hypocrite and saying I deserved it, are not even in the same ballpark!
I strongly resent your assertion that I was attacking your character. I was taught a long time ago that you criticize the action, not the person.
I know you have a better mic than the Rat Shack but I would be interested in seeing you plot the 1/12 octaves using the rat shack meter as compared to the reading with your mic. Just to see how accurate the rat shack really is.Zack - the RS meter is C-Weighted. It needs correction for the C-Weighted scale. In addition, it needs correction for its own inherent inaccuracies.
The B&K sound meter is also C-Weighted and needs the same C-weighted correction factors to obtain an unweighted response. But it is considerably more accurate than the RS meter.
For example, the pure (theoretical) C-weighted correction factor at 16 Hz is 8.4 dB. The RS meter correction factor at 16 Hz is 11.5 dB - a difference of 3 dB. That 3 dB difference is the error introduced by the RS meter. The B&K does not introduce any appreciable error other than that intentionally prescribed by the C-Weighted curve.
The Behringer ECM8000, despite being advertised as a full range measurment mic, also introduces error into the response curve, even though it is not weighted per se. I have seen no less than five FR sweeps for the ECM8000 against a known NBS-traceable reference standard, and all five of them started to trail off below 25 Hz and were all about 5-8 dB down at 10 Hz. And they were all somewhat different looking curves. This demonstrates the need to professionally calibrate any measurement mic against a known absolute reference in order to correct for its response error. Including your own specific mic preamp is also a good idea, since preamps do not have perfectly flat responses either.
Ed's response to you was harsh, but I'd probably respond the same way.I went back and re-read my original post. My choice of words was very poor and Ed had a legitimate right to be upset with them. It was not my intent but I could see how Ed could have reacted very strongly. I'm not condoning his attack on my character but I am taking responsibility for wording things poorly and instigating his strong response.
I am very sorry that I played a major role in undermining this effort. My intent was to do the opposite. I would have been glad to contribute time and effort to make it as good as it could be.
Ed's offer was indeed very generous.
This will be my last post. I am dropping the matter.