Use audyssey MultiEQ or an SPL Meter, which?

[Flint]

I totally agree, Pauly. After reading dozens of enthusiastic posts over a period of several months about the Mobile Pre & TrueRTA use by S&V members I finally bought them. Followed the instructions that came with the products and the writeups that S&V members posted, only to run into all kinds of problems. Inconsistent results which didn't remotely resemble what I was hearing or what my other spectrum analyzer showed. Finally I decided that it was a totally worthless, undependable test setup and a complete waste of money.

That is a real shame. The reason so many of us used TrueRTA and the common hardware solution was that we got previously unheardof results for such a low price. Today there are other options which may be better for similar costs.

While I never had an experience like yours, I can see why it would be frustrating to have that happen.

 

[yromj]

TrueRTA is a great piece of software. I think we may need to find a different sound card solution to recommend though. Many of us are having the same issues with the MobilePre.

John

 

[Flint]

I've used two piece systems, like a Blue mic input and the internal sound card. That works.

 

[malsackj]

I have been using a Quattro from M-audio on a laptop running XP. In the ANS Gym project you will see the graphs from running Room EQ wizard and the decay plot. I also use the True audio RTA and we have good success with both programs. The room EQ wizard sweep helps with running crossover adjustments quickly.

Room EQ wizard is on the hometheater shack

 

[Razz]

While at Bats last GTG, Pauly and a few of us were tweaking with TrueRTA for a few hours. Most of us thought it was great to compare subs and see what an impact the different subs had, but as for EQ its just all over the place. Moving the mic even 1 foot would have a serious impact and so it was decided to just leave things as it was.

 

[Flint]

While at Bats last GTG, Pauly and a few of us were tweaking with TrueRTA for a few hours. Most of us thought it was great to compare subs and see what an impact the different subs had, but as for EQ its just all over the place. Moving the mic even 1 foot would have a serious impact and so it was decided to just leave things as it was.

TrueRTA (or any analyzer) must be used differently for low bass measurements than for fullrange measurements. First off, due to room acoustics I typically make three to four measurements from different mic positions and average them together to get a more accurate curve of the overall response in the listening area. Secondly, you need to set the sampling rates of the analyzer to a much lower rate to increase the resolution of the bass measurement, which in turn slows down the sweep speed and increases the impact of the room acoustics. I have also been known to use Pink Noise instead of a sweep to measure bass on the fly, setting the "samples" to about 50 to 100 to average the random characteristic of the noise.

Ultimately, bass requires slowing down the whole measurement process and thus increases the amount of time it takes to capture accurate and useful data. I've written about it a hundred times over at the old forum, so I have been assuming everyone knew this stuff.

 

[PaulyT]

Yeah, I do time-averaged slow samples of pink noise like that when I'm really seriously doing EQ work. At Bat's we were mainly setting relative levels and so weren't being quite as rigorous. But yes, you could clearly see when the RTA was going with pink noise and fast sampling, that the bass especially would change quite a bit as you move the mic around the seating area.

 

[Rope]

XTZ Room Analyzer

Rope