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Joseph7195
04-19-2012, 04:20 PM
I am going to be doing some major SQ tuning an was going to buy this:

Dayton Audio OmniMic V2 Precision Audio Measurement System 390-792 (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=390-792)

Anyone have any ideas on other RTA's that would be comparable to this, or anyone have any personal experience with multiple RTA's? Only one I have ever used is the Goldline RTA, and it was expensive.

Just seems there might be some other companies I might be overlooking that could be more inexpensive and offer more for the price.

Any help would be greatly appreciated!!

Joseph7195
04-19-2012, 08:38 PM
Ttt

keep_hope_alive
04-20-2012, 01:24 AM
Yea, I use TrueRTA and a Beringer ECM8000 with a few different USB mic preamps. Works well. Biggest issue is controlling noise in the laptop.

We usually have to turn off various items, such as wifi and anything else not necessary for measurements. As such, we have dedicated laptops.

slim2fattycake
04-20-2012, 01:27 AM
SPL-Lab RTA pro. :)

CHRIS 323
04-20-2012, 01:41 AM
audiocontrol RTA ill say if you have $1500

kmanian
04-20-2012, 01:58 AM
I have used the Audio Control, Linear X and Coustic, and all are easy to use. I personally have and use thr RTA33 now because it is stand alone, and functions well.

Joseph7195
04-20-2012, 09:14 AM
Thanks Fella's, this is the exact type of info I need! If anyone else have any other ideas, let me know!

Bettr n' Revrse
04-20-2012, 09:18 AM
Your gunna get that serious into SQ huh?

Joseph7195
04-20-2012, 09:24 AM
Your gunna get that serious into SQ huh?


Yep, I am gonna get back into the technical side. I am kinda excited, but still a little daunted about how much technology has become more and more complicated over the years. Back in the day you had one screen and a bunch of lights, nowadays the software has more variables and graphs than I have ever seen. I hope I can make use of the information, instead of it going over my head and being useless. But I have gotta get on board the technology wave or get left behind!

Bettr n' Revrse
04-20-2012, 09:27 AM
Id like to have one as well but will worry about what the next setup will be first lol

Joseph7195
04-20-2012, 09:46 AM
Id like to have one as well but will worry about what the next setup will be first lol

I have a feeling with the horrible acoustics of my truck, I am gonna end up changing things a million times! But on the brighter side, I am gonna put up some advertisements to check SPL measurements locally and see if I can manage to make some of the money back for the software and hardware

keep_hope_alive
04-20-2012, 09:47 AM
i use an RTA on a regular basis, not just for my car but for work.

i just sold my second Behringer 8024 - was a 1/3 oct RTA and EQ. Sold it for $200, but you can find them for under $100. The replacement model is the DEQ2496. these are stand-alone and could be inserted in the signal path.

I also have an older Casella CEL-490 at work I can use (was $7k new and we got it for $3k used/calibrated). It's a Type-1 measurement instrument. Casella has a host of hand held 1/3oct SLM's. It's eerily accurate.

The benefit of the laptop approach is the ability to easily save and compare. I would measure each driver separately, from each seat, then measure each combination. all in under 20 minutes. then i can go back and look at the results and/or adjust eq/crossover while monitoring real-time. Also, with a 2 channel USB Mic Pre (I use the SoundDevices USBpre) you can have a mic at driver and passenger at the same time.

Example, this was a tuning effort last year, mic at each headrest:

without sub
http://i38.photobucket.com/albums/e128/phat_funky_beats/accord/AccordRTA_LR_midhigh_3rdtuned.jpg

http://i38.photobucket.com/albums/e128/phat_funky_beats/accord/AccordRTA_LR_midhigh_24thtuned.jpg

with sub
http://i38.photobucket.com/albums/e128/phat_funky_beats/accord/AccordRTA_LR_all_3rd.jpg

maybe my constant access to several different RTA's over the years has made me so used to using them, I don't think twice.

Bettr n' Revrse
04-20-2012, 09:50 AM
I have a feeling with the horrible acoustics of my truck, I am gonna end up changing things a million times! But on the brighter side, I am gonna put up some advertisements to check SPL measurements locally and see if I can manage to make some of the money back for the software and hardware

Great Idea! Maybe I will get one and do the same cuz no one in town has a meter... Keep me posted on what you find... Im doing a small scale budget SQ build in my truck right now as well...

Joseph7195
04-20-2012, 10:08 AM
i use an RTA on a regular basis, not just for my car but for work.

i just sold my second Behringer 8024 - was a 1/3 oct RTA and EQ. Sold it for $200, but you can find them for under $100. The replacement model is the DEQ2496. these are stand-alone and could be inserted in the signal path.

I also have an older Casella CEL-490 at work I can use (was $7k new and we got it for $3k used/calibrated). It's a Type-1 measurement instrument. Casella has a host of hand held 1/3oct SLM's. It's eerily accurate.

The benefit of the laptop approach is the ability to easily save and compare. I would measure each driver separately, from each seat, then measure each combination. all in under 20 minutes. then i can go back and look at the results and/or adjust eq/crossover while monitoring real-time. Also, with a 2 channel USB Mic Pre (I use the SoundDevices USBpre) you can have a mic at driver and passenger at the same time.

Example, this was a tuning effort last year, mic at each headrest:

without sub
http://i38.photobucket.com/albums/e128/phat_funky_beats/accord/AccordRTA_LR_midhigh_3rdtuned.jpg

http://i38.photobucket.com/albums/e128/phat_funky_beats/accord/AccordRTA_LR_midhigh_24thtuned.jpg

with sub
http://i38.photobucket.com/albums/e128/phat_funky_beats/accord/AccordRTA_LR_all_3rd.jpg

maybe my constant access to several different RTA's over the years has made me so used to using them, I don't think twice.


This is the reason I am thinking of going with the computer software, mainly the easy comparisons and ability to save and compare. The second picture down, does the separate peaks between the speakers around the 1100 hz to 1300hz area denote signal reproduction differences, or time arrival differences, and if it is time arrival, do I superimpose the green speaker to the left to the purple, or purple to the right to the green, and then would the delay be applied to the left speaker or right to get the right response movement?

This is gonna be fun, but I am way out of my comfort zone with things like this^^^. I am hoping I am just making it harder than it will actually be.

keep_hope_alive
04-20-2012, 02:47 PM
Arrival times don't shift frequency, just affect phase interference - I.e. amplitude. Peaks could be reflections. Those two peaks are likely constructive interference. If they are within 3dB you won't notice. We barely perceive a 2dB difference of single tones. My goal is to be within 5dB peak-to-peak in the vocal range. That results in a pretty natural reproduction.

Also, test various mic positions.

This is why measuring one diver at a time and saving each, has benefits. I still have the files for all my RTA tests. I can review and compare any combination, as many at a time as I want, and I can export to excel. I like TrueAudio, for $100 it's a good deal with 20 memory spots, and you can combine or create annother file for 20 more. Add a $50 measurement mic and you're only missing a preamp with 48V phantom power. Several to choose from.

Note the laptop should run on battery during tests, chargers generate noise.

USBpre is around $650 but it's **** good and good down to 10Hz. For work I actually care to measure as low as 5 Hz. But that low we use an Earthworks m50 mic. Below that we use a hydrophone which can measure below 1Hz.

Joseph7195
04-20-2012, 04:41 PM
I have some experience with recording, just in a open venue, never in a closed environment like a car. Usually the stage mics wouldn't interfere with anything and reflections were pretty much nonexistent. When I started trying to apply my knowledge of stage and studio recording and acoustics to a vehicle, everything change. It requires a new way of thinking to make things work. Also it's been a couple years since I have been traveling the country recording, so I am rusty on just about everything.

The only downfall I can see with the Dayton software from PE, is that it doesn't have a way to measure phase shifts (other than being a little higher than I want to spend) so I am really considering buying the Trueaudio software and mics and preamps separately (I already have a sound card). Only thing I am worried about is being on the road and wanting to make adjustments and having to find a place to plug in my phantom power mic preamp. But I think most shows are held pretty close to an electrical source

keep_hope_alive
04-20-2012, 09:47 PM
i prefer battery or USB powered mic preamps. saves needing 120V completely.

keep_hope_alive
04-20-2012, 09:51 PM
CEntrance -> MicPort Pro (http://www.centrance.com/products/mp/)

http://www.centrance.com/products/mp/i/micport_pro_alt_200.jpg

i've used this. works out well. can be plugged into the mic directly but then holding it is a chore.

M-Audio Fast Track USB | Sweetwater.com (http://www.sweetwater.com/store/detail/FastTrkUSB2/)
M-AUDIO - Fast Track - Record Guitar and Vocals on Your Computer (http://www.m-audio.com/products/en_us/FastTrack.html)

http://electronicmusictutorials.files.wordpress.com/2010/12/maudiofasttrackusbmk2.jpg

haven't used the M-audio model (this is the newer one) but it is a similar concept (bulky)


you will want a separate 1/2" calibrator as well - if you want to know actual SPL levels. otherwise, the measurements are relative.

keep_hope_alive
04-20-2012, 09:56 PM
this is what we use:
USBPre Microphone Interface for Computer Audio | Sound Devices, LLC (http://www.sounddevices.com/products/usbpremaster.htm)
http://www.sounddevices.com/images/products/usbpre_large.jpg

i have one of these in my garage right now. requires 120V power or a 12VDC socket. but you can use your own sound card. and it's cheap.
Rolls MP13 Mini-Mic Microphone Preamplifier at zZounds (http://www.zzounds.com/item--RLLMP13)

M-Audio does have a 2 channel USB version that should be compatible with TrueRTA. Cheaper than SoundDevices.
M-AUDIO - MobilePre - Record Music with Your Computer (http://www.m-audio.com/products/en_us/MobilePre.html)

USB mic pre's will replace the sound card in your laptop. you don't want to rely on the factory sound card, but a PCIMA sound card (like Soundblaster) so you get lower noise and better resolution. the price of a PCIMA sound card goes a long way to pay for a USB mic pre that will act as the sound card.

slim2fattycake
04-29-2012, 03:18 PM
Just in case someone is interested. This is a hell of a deal for an RTA. SPL-Lab USA wants to play a game&#33 (http://www.soundsolutionsaudio.com/forum/topic/55355-spl-lab-usa-wants-to-play-a-game/) - SSA Car Audio Forum