james840a

iTrader: (7)

I finaly broke down and bought one for my personal use. Found the PAA3 handheld audio analyzer at samash. Not bad price ether.
It analyzies the audio with the test CD and then tells you what levels at the Hz you need to adjust to get a flat response using a 31-band EQ.

Im into have good SQ system, I also been listing to my audio system out side the car, looking for those pesky rattles and found 3, fixed 3

Paul350Z

iTrader: (1)

Sweet.

When you're done with it would you like to loan/rent it out?

I have been trying to get up a system for myself and was looking at going with an M-Audio USB interface for my laptop and then RTA software running on the computer. That's a nice looking little one piece solution.

I figure that I could use it at work where I set up some the auditorium and some of the radio, and marketing and promotion listening areas ... hey boss

bjr

Let us know how it turns out for you. I wanted to do the same and tried the poor man's way with a dB meter and test tune CD in 1/12 octave intervals. Sounded great until I started the car and actually drove it! Very different with road noise. Maybe you could have a passenger run the RTA while you drive it around
Seriously though I didn't have experience in this area and didn't know what I was in for so if I can warn you ahead of time I will. Good luck!
BTW do you have that many bands of EQ?!
Where were your rattles? I am currently turning my volume up to cover mine! I'm sure that they are actually coloring the music somewhat even when I drown them out.

16psibrick

iTrader: (10)

cool, remember that a perfect setting ont he RtA doesnt mean it sounds good...but those rea helpful wiht finding cancellation points and the big valleys and dips.

I used to borrow a freind of mine's ears, who is a professional recording technician, to tuen my music to his reference levels after a inital run through the RTA

never had the chance to do wtih my current set up though, just went throuhg my 31 bands of eqing by my own ears

james840a

iTrader: (7)

Paul350z, sorry i dont loan/rent out my tools. But if youd like we can get together on a weekend day and do a car audio tune since your location is Riverside. I havent recieved it so dont know how it will work out, but im pretty sure it will do a great job. If your looking to use it for work, the unit is only $399 witch is not bad price. I to was going to use the RTA software. Infact i ran acrossed this handheld unit when i use looking for the Specail mic for the RTA software and desided to get the handheld unit.

BJR, Yeah, im going to do a two step audio test, one while the car is off, and one while driving, passenger will operate the unit while i drive. The three rattles i found were at the license plate, its the black tabs that slide onto the bumber with the nuts that bolt the plate on, used dynamat to hold them. The second one was the exhaust heat sheild under the car just infront of the rear wheels. The third was the black cover over the third brake light, it rattles againts the window even tho it had a rubber ring on it. i use some black strech carpet worked great. But since i added my new Alpine Type-X i found acouple new rattles. BJR, yep my alpine pxa-h701 has a 31-band EQ per 5.1 channel.

I should be getting it Tuesday, but ill keep you posted.

bjr

Thanks for the tips. Good luck. I seem to remember that everything below like 300Hz is boosted in the car with it off and I cut by as much as -18dB at a couple of frequencies. I've got a 5 band parametric. Once I drove it everything went back to almost flat setting with a little cut in the 100Hz range. Could be that this is near my crossover points too. Not sure how to determine the best crossover points exactly, an RTA would be really helpful for those kinds of things I am guessing Have fun...

james840a

iTrader: (7)

Just recieved my PAA3 today. WOW this thing is cool.
Here is some info on the box.
31-band Real Time Spectrum analyzer
31-band EQ setting value display (boost/cut calculations)
RT60 measurement
Built-in calibrated measurement mic
Phase checker
Noise generator with pink noise, 1khz and polarity test signal, balanced output
memory and avg calculation function
SPL meter calibration through sound level calibrator
Sound pressure level meter from 30db-130db
line signal measurement display in dbu, dbV, or volt(ac)
SPL meter and level meter have three level range
Maximum level, peak hold display
XLR input and output sockets
USB interface for desktop software control
Audio test signal CD and supporting software
AC power adaptor included
Three power modes

Paul350Z

iTrader: (1)

So how is the PAA3 in use?



Edited to add - is the software in English and does it run on Windows XP? Apparently the PAA2's runs on Windows 98 and the XP version is in German?

james840a

iTrader: (7)

This thing is awesome. Yes the software i got with it is running on XP and is in english
It is very easy to use. after adjusting my eq it looks like a roller coaster, up and down. But when you listen to it, it sounds nice. For the most part i was able to get a +/- 1-2db to a flat responce witch is good enough for me

Paul350Z

iTrader: (1)

+/- 2 dB is outstanding in a car!

bjr

Did you do a comparison of car off and driving down the road? I guess this depends on what sound deadening you have done but still should be a significant change, especially bottom end needing some boost to be heard??
Just curious.

Paul350Z

iTrader: (1)

I think it would be interesting to do a spectrum capture with the stereo off and the car running down the highway in top gear at 65 mph (OK 80 mph in California ). The SPL level is going to be pretty high. A good loud system is going to smoke even that high level by huge amounts.

Just making a WASG I would think my car is about 50 dB +/- at highway speeds and that when I've got the music too loud for converstation I've got the stereo up at 80 dB ... and it can get a bunch louder than that if I'm interested in pain and additional stereo caused hearing losses.

If the spectrum analyzer shows a loud 2400 hertz peak caused by the engine/drive train you would not want to boost the audio at that point to compesate - you would tilt the music and it would sound like carp. I can't speak to rap music (or most dance music) but classic audio from the dawn of time to the 1980's was mastered in a control room with the producer listening to a system that was tuned as flat as possible. Normally you would adjust the room's accoustics by changing the dimentions, size, wall, floor, and ceiling treatments to flatten the room as much as possible. Then moving the furniture and speakers around and then only when all other possible solutions had been exausted would you dare tweak the playback sound to compensate. It's really hard to do anything in a car except to equalize the playback.

bjr

Paul 350z - I agree with what you just said.
I set my system as flat as I could sitting in the garage. Sounded nice. The only EQ changes I really made was to make a couple of huge cuts in the very bottom end to eliminate the car's natural boost at that frequency. Most cabins have a transfer function that boosts certain low frequencies, no?
I would agree that your 50dB guess is pretty acurate, however you only get these kind of readings on the highway if you put a dB meter on A weighting (500Hz - 10,000Hz). Switch it over to C weighting (30-10000Hz) and you are talking about well over 100dB of noise. So when I went for a drive I could not hear the bass over the road noise. When turned up the sytem just sounded like all highs. Basically it just sounded like an very clean stock system with nicer front speakers. No full range sound - bottom end still missing. The bass never "caught up" and overcame the road noise is how I would try to put it. I tuned the EQ by ear driving and ended up with what I like for everyday but sitting in the garage it can sound overboosted and boomy on most material - enough bass to make it unlistenable on material that already has a lot of bass mixed into it. I always have thought that car audio is supposed to be more "fun" anyway than home system where I would run one device (cd player usually) through a pre-amp with only stepped attenuators in it for volume straight to the amp. I would never even think about adjusting anything about it and in most rooms it sounds awesome.

With it tuned to sound more "well rounded" on the road I can get 127dB no problem so I don't know why on the first "flat" settings the bass was so inaudible on the highway. I also agree with what you said about boosting a music frequency to overcome a noise at the same frequency will end up with music sounding like crap - but since I haven't sound deadended yet I don't know what else I could do. And sound deadening will only get you so far.
Not only does the noise seem to alter the balance of all of the frequencies but it also distracts you from the soundstage somewhat. But that's a whole 'nother subject. My question was basically only about the bass being muffled by the road noise.


james840a - You didn't feel the need to readjust anything after your first road test then??
Congrats on getting such a flat response in a car! Did you do any fine tuning by ear or did you leave it flat? What differences do you note between car off and car on/driving?

16psibrick

iTrader: (10)

just curious, but arent you suppose to tune it so it shows a gradual downward slope on the rta, instead of flat? thats waht i been taught...

b

bjr

james840a -
Would you be able to tell us what the transfer function is like for a Z? Basically how much dB gain we're getting on subs and vaugely what frequency range most of the boost occurs?
Thought you might have discovered this while tuning or at least could look back at what you did and give us a good guess.
I'm not sure I have the equipment to figure it out myself and searching the internet so far has yielded that hatchbacks you figure 16dB gain but no reference to what frequencies. I'm sure it varies from different models of hatchbacks as to what range though.

thanks!

bjr

After searching for awhile I only found one useful web page. It seems one rule of thumb is a 12dB/octave cabin gain for all frequencies whose wavelength have there fundamental wave outside the car. The Z is 103" between back trunk wall and where the windshield meets the dash.
Wavelength=speed of sound/frequency
so starting at about 131Hz there should be a 12db/octave boost.

Still cuious if this would correlate with anything you learned from your RTA.