REW review and comparison to AP System 1

**clubfoot** · **09-13-07, 09:15 AM**

Thought some of the more knowledgeable REW members would like to see this post and add their own take.

See the complete review of SPL meters and other high end gear in the link below, no actual data.
His very brief summation of REW's performance and mention of "marketing department" left me with serious doubts of how much time was spent actually setting REW up properly.

And I quote:
Room EQ Wiz is a free software package. It is unfortunately not a good performer in absolute measurements and certainly poor in terms of repeatability. Above 500Hz, the performance is better, but the resolution is so low that I would be reluctant to accept any test data based on that platform.

http://www.hometheaterforum.com/htf/...d.php?t=261907

**Sonnie** · **09-13-07, 01:15 PM**

Well... I'm certainly not sure how to respond to it because he gives no data to back up his claims. Without data, it's just words. How inaccurate is it below 500Hz... is it off by 1Hz, 2Hz, 10Hz... all over the place?

He also says this:

Quote:

Maybe it seems I am being unfair to REW- I am not. I can put it in context as saying that I am accustomed to getting spot on results on audio and electrical measurements. We pay the bills by this stuff and it is up to me in my company whether to accept measurements or not. If someone gave me a curve from REW, I would question the accuracy below 500Hz based on what I have observed in our lab and listening room.

Is REW a cool program? Absolutely.

Is REW done by some cool folks? No question about it.

Could I write a better program? Not a chance; forget it.
Could the program be better? Yep, but keep in mind the cost.
Is it a lab quality program or suite? Unfortunately not, but I do not think it is intended to be that at all- My hat is off to the folks that are dedicated enough to write it for free and give it away for free. Great job; we need more folks like you in the industry.

If soneone wants to nit pick this to death, please check all my spelling, the facts and so on... I am doing this for free as are the REW people. So if you have some nit pic commentary...... My response will be something like- 'Yo momma.

He says "...check all my spelling, the facts and so on..."

The fact is... he gave us no facts because he did not qualify his testing with data.

Not trying to be unfair and not trying to be nit picky... JohnM is doing this for free, so my response to Phase is simply... "yo momma".

**JohnM** · **09-13-07, 01:47 PM**

I've replied to the poster on the forum where he posted. I've used both MLSSA and AP Systems 1 and 2 to verify REW, along with several other commercial acoustic and electronic measurement applications. It is extremely accurate.

**Sonnie** · **09-13-07, 02:09 PM**

If you read through all of what he posted... it appears he's making a lot of assumptions based on their labs testing procedures which also seem to have made a lot of assumptions.

Again... no data=no facts

Although you requested the data John, sounds like they aren't going to release it.

**brucek** · **09-13-07, 02:48 PM**

Quote:

Although you requested the data John, sounds like they aren't going to release it

Well, and the fact that the guy says if you disagree with him, he'll respond with a "Yo momma".........

Who would post something so negative and then say they aren't willing to discuss it or back it up with any data.

brucek

**Sonnie** · **09-13-07, 03:38 PM**

That guy is sniffin' glue...

**clubfoot** · **09-13-07, 05:24 PM**

I not a programmer, but from all that I've read about REW, it is probably one of the least "intrusive" and repeatable software measurement tools out there. I think I'm still in shock as to why someone would make a post like that and not provide some substance, so that John could take a look and see if the program needed tweaking or something.

That's why I this is one of my favorite forums, because we spend allot of time helping each other get the best we can from our setups with good sound advice backed up with data.

And he sounds very defensive!

**Wayne A. Pflughaupt** · **09-13-07, 05:41 PM**

C’mon, folks, let’s don’t get our feelings hurt just because “we have a dog in this race,” as it were. I think we’re bigger people than that.

I don’t think Phil really has any axe to grind with REW. That said, it’s not entirely clear to me exactly what he was evaluating, but I think he was using a number of test platforms (I guess that’s what REW would be to him) to evaluate the accuracy of various SPL meters and microphones. I’m not altogether sure how REW could do this (brucek?). After all, we’ve had to rely on outside calibration files for the RS meters, not an internal self-calibration, like with the soundcards, which have both input and output connections.

Phil’s main “beef” seems to be repeatability. I assume he knows that any real-time, in-room measurement is not going to be 100% repeatable anyway (anyone who’s taken back-to-back measurements with REW or some other software package knows this). Perhaps that’s where the MLS time window and tracking filters he mentioned come in to play (I won’t pretend to know what those are).

Even if REW isn’t “laboratory grade” on par with the $25k AP system, so what? I doubt John designed it as such to begin with, and he certainly didn’t design it as a platform for testing microphones. We really don’t need anything laboratory-grade for what we’re doing – i.e., in-room measurements, which are going to vary from day to day with changes in temperature and humidity, and other room-related factors as well. Regardless, if I’m reading Phil’s report correctly, IMO the main “monkey wrench” in the works is not REW itself, but the Radio Shack SPL meters, since he found their calibrations varied from one to the other (not the soundcards, as he indicates – REW can self-adjust for them).

Regards,
Wayne

**Sonnie** · **09-13-07, 05:59 PM**

He certainly hasn't hurt my feelings because he hasn't proven anything thus far. What I don't appreciate is the fact he makes claims that he can't back up with any data. If you are going to make such claims about a product, you should be willing to provide the data. You think Ilkka would have any merit if he tested a sub and simply said that it was a poor performer and the manufacturers claims were not accurate, but he refused to provide any data to support his claim? Ohhh-no... that dog won't hunt my friend. This is about as unprofessional as it gets. If I owned the company that Phil worked for, he would be fired.

We have already verified with available data that RS meters can and do vary from meter to meter. That's nothing new.

**Wayne A. Pflughaupt** · **09-13-07, 06:15 PM**

I’m not sure more detailed data would do most of us any good, unless you can understand the other stuff he wrote:

Quote:

Listen and Clio were nearly identical. Gauge R&R comparing the systems has Clio on top by a slight margin. I would like to note that the accepted error margin here is greater then the separation of the 2 test platforms.
Both outperformed the AP in terms of R&R testing.
MLSSA measurements were right there with Listen and Clio, but as many of you already know, the MLSSA platform has heat soak issues.
LMS comes in at about the MLSSA level; depending on the mic.
You simply can not compare a maxed out Listen rig to the basic LMS bundle and say that it is fair.
LMS has acceptance going for it and it seems that even the competitors agree as they will all import LMS / Leap format data.

I know I sure don't!

Regards,
Wayne

**Wayne A. Pflughaupt** · **09-13-07, 06:25 PM**

The SPL meter was the topic of the thread anyway; not sure why even included the stuff on the platforms. Certainly wasn't relevant.

Regards,
Wayne

**Sonnie** · **09-13-07, 06:26 PM**

I think he (or their tech) would need to explain the procedures used to verify REW is supposedly inaccurate and provide data, graphs, measurement examples, whatever they are looking at that shows the inaccuracies.

We don't even know if the tech had REW setup correctly... or if it was really even tested.

**brucek** · **09-13-07, 06:43 PM**

Quote:

I’m not sure more detailed data would do most of us any good, unless you can understand the other stuff he wrote:

Well, that's the point isn't it it? Everyone at HTF reads this list of very technical sounding gobbledygook and concludes that this guy must really know his stuff, so it gives undeserved weight to his unsubstantiated claim that REW isn't accurate.

I have always thought that it must be a bit of a thorn in the side of the people who write and sell for profit the other measurement software in the market. How annoying to have a product that is arguably better, sell for free.........

Johns time, and mine, and yours, and everyone elses time here at HTS is quite valuable. Yet we give it away for free.

I happen to think REW is quite a good program and very accurate. I take exception when someone says otherwise and claims to be a professional. Yet they won't supply any data to prove it, and if we disagree with anything other than his spelling, his professional response will be "Yo momma'........

brucek

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