The RTA Walkthrough and Usage thread. With Video. - Page 3 - Car Audio | DiyMobileAudio.com | Car Stereo Forum

 02-23-2013 #51 DIYMA Enthusiast Join Date: Sep 2009 Location: Calgary, Alberta Age: 46 Posts: 1,741 Thanks: 0 Thanked 2 Times in 2 Posts Rep Power: 113 iTrader: (7) Re: The RTA Walkthrough and Usage thread. With Video. I can't possibly be the only one with this potentially stupid question but... How does such a decay plot tell me where I need to do some work with sound deadening?

02-23-2013   #52

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This is from my build log. It's a good example of how the impulse method gives you more insight in to your system.

Again, I'll document how to do this via video at some point soon. I'm just trying to get through some other stuff first.

Quote:

-- SQ is great, but sometimes nostalgia is greater. --

http://medleysmusings.com/

Time Delay Calculator:
http://tracerite.com/calc.html

My 2006 Honda Civic LX Sedan Build Log

 02-24-2013 #53 DIYMA Regular Join Date: Apr 2008 Location: Central PA Posts: 546 Thanks: 0 Thanked 0 Times in 0 Posts Rep Power: 119 iTrader: (2) Re: The RTA Walkthrough and Usage thread. With Video. Hey Erin, Some thoughts and questions on video #1 (basic RTA). Your technique for obtaining a smoothed and averaged plot is to take multiple individual measurements at the full spectrum, smooth them to an octave width, and then average them together over a few separate steps. I've always had the software (True RTA or REW) do the smoothing and averaging while taking the data. Basically, I've set the mode in REW to measure directly in 1/3 octaves and set the averages to a high number. Then, while the pink noise is playing, I move the mic slowly around the headrest to get a continuous average until the curve stabilizes (30-60 seconds). I've found it to be very reproducible. Does the more manual method you've described offer any advantage to this? I've always liked my approach because I can get my output in one step versus multiple steps otherwise. When I'm tweaking the EQ for small changes, I can see my results relatively quickly this way without having to do a lot of software manipulation. Thanks and great vid! I'm looking forward to part 2 because I think I've reached my limits with basic RTA. I've gotten a pretty good output with it, but there are just some things I cannot fix with the data I've got. 2007 Ford F350 * Kenwood DNX7100 * RF 3sixty.3 * JL Audio 300/4 * JL Audio 500/1 * Pioneer TS-C720PRS * JL Audio 13TW5v2-2

 02-24-2013 #54 Bikinpunk Join Date: Feb 2007 Location: North Alabama Age: 34 Posts: 17,152 Thanks: 45 Thanked 85 Times in 38 Posts Rep Power: 25981 iTrader: (94) They're similar, if not all but the same. I honestly forgot to use the averaging method here. I typically set averages to high and measure multiple instances. The reason I do this outside the car method is simply that I haven't found an appreciable difference worth cramming myself in to the back seat. Additionally, I'd have to use my NetBook to be in the car. I can't do the sweeping average method with the PC simply because I'd have to get back out. I will say I have measured all sorts if ways. I used to use omnimic with me sitting in the car. I still do sometimes. I really wanted the videos to be simplistic in nature. At least up through the point where people who are new get a handle on it. I don't want to scare folks always with all the crazy ways you can do it. Not yet. -- SQ is great, but sometimes nostalgia is greater. -- Follow my blog: http://medleysmusings.com/ Time Delay Calculator: http://tracerite.com/calc.html My 2006 Honda Civic LX Sedan Build Log
02-24-2013   #55

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Re: The RTA Walkthrough and Usage thread. With Video.

If the null is truly a cancellation null then I won't worry about it. I'll tackle that when I get there.

Boosts will be attacked via PEQ if they are too large to treat by other methods. Which, they most likely are. It would take a good deal of space consumption for mechanical bass absorption (ie: bass trap, or helmholtz absorber).

Quote:
 Originally Posted by cajunner Now you are able to correlate your subjective opinion with an objective graph, is this what you mean by full disclosure in your build thread?
Yes. That's exactly what I meant. I'll try to document everything I can. I'll also post it here, if it fits.

-- SQ is great, but sometimes nostalgia is greater. --

http://medleysmusings.com/

Time Delay Calculator:
http://tracerite.com/calc.html

My 2006 Honda Civic LX Sedan Build Log

 02-24-2013 #56 DIYMA Novice Join Date: Apr 2012 Location: SoCal Age: 36 Posts: 258 Thanks: 0 Thanked 0 Times in 0 Posts Rep Power: 67 iTrader: (0) Re: The RTA Walkthrough and Usage thread. With Video. After playing around yesterday, I had the feeling I was getting closer. Kid's upstairs taking a nap (valuable time!), so I figured I'd see what I could do. First up, the left and right channels individually (no sub), before making any changes today: And the stereo plot: There were a couple areas I knew I wanted to tackle in particular, so I started going nuts with the EQ. By the time the laptop battery died and the kidlet woke up, I got the plots to look like this: Which is better, but the whole range between 160-500 especially is too loud and after listening for a while, I wasn't convinced I made much (if any) improvement. One thing I've wondered about for a while is EQ. You don't see people post their settings, and there are a lot of comments out there that imply that with good equipment installed well, there shouldn't be a need for "much" (whatever that means) equalization. Then there's also the fact that when you only have a hammer, everything looks like a nail. By the time I finished, my woofer and midrange EQs looked like this: I'm honestly not sure if that's a lot, a little, or just average. I thought (and think) it's more towards the high end. The muddied up sound also made me think I was just making things worse by screwing with the EQ too much. Fast forward a couple hours, and I go give it one more shot, focusing especially on the mid-bass. Even more futzing with the EQ (nail, meet hammer...) and I get the RTA plots to this: And I'm proud-ish of myself for that, but the DSP settings look even wonkier, so I have low hopes for this round of changes: Sweet baby Jesus on toast! What. a. difference. Everything is better. Everything. It's like those Claritin commercials when they do the wipe effect and everything's clear and colorful. Finally I made some real progress. I still don't know if I'm doing any of this right or not, but damn am I ready for a celebration beer!
 02-24-2013 #57 DIYMA Addict Join Date: Nov 2010 Location: Sweden Age: 30 Posts: 4,701 Thanks: 0 Thanked 15 Times in 9 Posts Rep Power: 297 iTrader: (0) Re: The RTA Walkthrough and Usage thread. With Video. Looks good # In a time of universal deceit - telling the truth is a revolutionary act # (George Orwell) - Build Thread 1, Mercedes-Benz E 320T (2000) - - Build Thread 2, VW Passat 1.8T (2000) -
 02-25-2013 #58 DIYMA Novice Join Date: Aug 2009 Location: Anaheim CA Posts: 437 Thanks: 0 Thanked 0 Times in 0 Posts Rep Power: 175 iTrader: (5) Re: The RTA Walkthrough and Usage thread. With Video. subscribed. This is an excellent thread. Alpine CDA-9887 | Imagine I6 midbass, L1V2, P69, GZHA 4150XII, and B2 Precision waiting for install |
02-26-2013   #59

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Re: The RTA Walkthrough and Usage thread. With Video.

Hmm... had some time to lay with REW today after my Dayton UMM6 USB mic arrived.

However I can't seem to get rid of spikes at 1000Hz from 2kHz and up?

The noise measured is only background noise, but it is the same with different background noise

EDIT: measured my Bose Quietcomfort15 headset with pink noise
Attached Images
 Dayton mic spikes.jpg (47.1 KB, 86 views) qc15.jpg (37.6 KB, 76 views)

Last edited by Sonus; 02-26-2013 at 12:48 PM..

02-26-2013   #60

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Re: The RTA Walkthrough and Usage thread. With Video.

Quote:
 Originally Posted by Sonus Hmm... had some time to lay with REW today after my Dayton UMM6 USB mic arrived. However I can't seem to get rid of spikes at 1000Hz from 2kHz and up? The noise measured is only background noise, but it is the same with different background noise I've downloaded the cal file from daytonaudio.com and loaded it into REW. EDIT: measured my Bose Quietcomfort15 headset with pink noise
First picture looks like soundcard feedback issues. Run REW in loopback first and check your soundcard. If you got a Creative card, you might have issues in Win7 with the flexijack shit.

# In a time of universal deceit - telling the truth is a revolutionary act # (George Orwell)

- Build Thread 1, Mercedes-Benz E 320T (2000) -

- Build Thread 2, VW Passat 1.8T (2000) -

 02-26-2013 #61 DIYMA freshman Join Date: Jun 2010 Location: Norway Age: 41 Posts: 204 Thanks: 0 Thanked 0 Times in 0 Posts Rep Power: 89 iTrader: (1) Re: The RTA Walkthrough and Usage thread. With Video. I'm using a Samsung NP530U3B laptop runnning W7. However it hasn't got a seperat line out or mic in, but a combined jack with in and out on the same jack So I'd need to make up a "shorting jack" to loop the line out into the mic in to calibrate the "sound card"?
02-26-2013   #62

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Re: The RTA Walkthrough and Usage thread. With Video.

Quote:
 Originally Posted by Sonus I'm using a Samsung NP530U3B laptop runnning W7. However it hasn't got a seperat line out or mic in, but a combined jack with in and out on the same jack So I'd need to make up a "shorting jack" to loop the line out into the mic in to calibrate the "sound card"?
Uuh.. hate those combo jacks.

You should measure some speaker with a known frequency response in nearfield. And see if you get a reasonable flat response, otherwise you might have issues. Make sure the "listen on the device" is deactivated in the mic settings within the sound manager in Win7.

# In a time of universal deceit - telling the truth is a revolutionary act # (George Orwell)

- Build Thread 1, Mercedes-Benz E 320T (2000) -

- Build Thread 2, VW Passat 1.8T (2000) -

 02-26-2013 #63 DIYMA freshman Join Date: Jun 2010 Location: Norway Age: 41 Posts: 204 Thanks: 0 Thanked 0 Times in 0 Posts Rep Power: 89 iTrader: (1) Re: The RTA Walkthrough and Usage thread. With Video. I've got an old Bose Quiet Comfort 15 lead with mic that is broken. I might modify that so that the left and right line out is looped back into the mic line in. Just hope the wires are large enough to work with That should make it possible to calibrate the sound card I guess?
02-26-2013   #64

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Re: The RTA Walkthrough and Usage thread. With Video.

Quote:
 Originally Posted by Sonus I've got an old Bose Quiet Comfort 15 lead with mic that is broken. I might modify that so that the left and right line out is looped back into the mic line in. Just hope the wires are large enough to work with That should make it possible to calibrate the sound card I guess?
Output on left channel and input on right channel (or vice versa). Should be possible, yes.

# In a time of universal deceit - telling the truth is a revolutionary act # (George Orwell)

- Build Thread 1, Mercedes-Benz E 320T (2000) -

- Build Thread 2, VW Passat 1.8T (2000) -

 02-26-2013 #65 DIYMA Regular Join Date: Apr 2008 Location: Central PA Posts: 546 Thanks: 0 Thanked 0 Times in 0 Posts Rep Power: 119 iTrader: (2) Re: The RTA Walkthrough and Usage thread. With Video. Erin, Uncorrelated (stereo) or correlated (mono) pink noise? I always notice some dramatic differences at frequencies in the upper midbass, lower midrange region depending on which I use. Never knew which result was "right". Thanks again. 2007 Ford F350 * Kenwood DNX7100 * RF 3sixty.3 * JL Audio 300/4 * JL Audio 500/1 * Pioneer TS-C720PRS * JL Audio 13TW5v2-2
02-26-2013   #66

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Re: The RTA Walkthrough and Usage thread. With Video.

Quote:
 Originally Posted by charliekwin After playing around yesterday, I had the feeling I was getting closer. Kid's upstairs taking a nap (valuable time!), so I figured I'd see what I could do. First up, the left and right channels individually (no sub), before making any changes today: And the stereo plot: There were a couple areas I knew I wanted to tackle in particular, so I started going nuts with the EQ. By the time the laptop battery died and the kidlet woke up, I got the plots to look like this: Which is better, but the whole range between 160-500 especially is too loud and after listening for a while, I wasn't convinced I made much (if any) improvement. One thing I've wondered about for a while is EQ. You don't see people post their settings, and there are a lot of comments out there that imply that with good equipment installed well, there shouldn't be a need for "much" (whatever that means) equalization. Then there's also the fact that when you only have a hammer, everything looks like a nail. By the time I finished, my woofer and midrange EQs looked like this: I'm honestly not sure if that's a lot, a little, or just average. I thought (and think) it's more towards the high end. The muddied up sound also made me think I was just making things worse by screwing with the EQ too much. Fast forward a couple hours, and I go give it one more shot, focusing especially on the mid-bass. Even more futzing with the EQ (nail, meet hammer...) and I get the RTA plots to this: And I'm proud-ish of myself for that, but the DSP settings look even wonkier, so I have low hopes for this round of changes: Sweet baby Jesus on toast! What. a. difference. Everything is better. Everything. It's like those Claritin commercials when they do the wipe effect and everything's clear and colorful. Finally I made some real progress. I still don't know if I'm doing any of this right or not, but damn am I ready for a celebration beer!
Hey Charli,

I liked this part of your message: "One thing I've wondered about for a while is EQ. You don't see people post their settings, and there are a lot of comments out there that imply that with good equipment installed well, there shouldn't be a need for "much" (whatever that means) equalization. Then there's also the fact that when you only have a hammer, everything looks like a nail."

The reason for buying high end equipment - at least in my point of view - is that you buy a product in which the manufactur spent a lot of time for R&D and it gets you the results with the smallest ammount of efforts to get it sound right.

Today for HU's and Amplifiers - I don't see the need to spend so much money as most HU's today, even the most simple and cheap ones (for example 2din multimedia untis that are carpc based - excellent RCA signal, very clean) and as well you can get extreemly strong amps with very low disturtion at a funny cost comparing to good few years behind.

BUT! when it comes to speakers and install -> this is where it all goes CRAP

And this is exactly where high-end speakers would be better sounding on basic installs and basic tune up.

At this point the DSP with all its features - especially the equalizer comes in to picture and does its "magic" - if you have cheap speakers which are detailed enough and percise, with a good work done on your install and DSP (eq) you can get amazing results, most probably, with high end speaker - you will have much easier work getting there.

These are my 0.5NIS

Subi Legacy 10: Morel+HAT CDM880&L1v1+HybridOvation 602 Sub Audison TH10 BASSO Audison VOCE AV5.1K FullDA Nexus7+SabreDAC with Audison Bit One running the show

02-27-2013   #67

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Quote:
 Originally Posted by mooch91 Erin, Uncorrelated (stereo) or correlated (mono) pink noise? I always notice some dramatic differences at frequencies in the upper midbass, lower midrange region depending on which I use. Never knew which result was "right". Thanks again.
Use uncorrelated (stereo) for FR measurements.

Sent from my Samsung Galaxy 3 via Tapatalk.

# In a time of universal deceit - telling the truth is a revolutionary act # (George Orwell)

- Build Thread 1, Mercedes-Benz E 320T (2000) -

- Build Thread 2, VW Passat 1.8T (2000) -

02-27-2013   #68

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Re: The RTA Walkthrough and Usage thread. With Video.

Quote:
 Originally Posted by eddieg quoted stuff

i should have taken some shots of what i did with tintworx's sutff. it took a while to get use to the quirks in the mosconi 6to8... im not a huge fan of the software. backing out and going back into the other menus to mute and what not is really annoying after a while... but it is powerful. the fact that there are different eq types for each pair of channels kind of sucks though.

this is all i took with his car

the video was helpful because the menus are kind of located in wonky spots - so yea. i would say get a tripod or something to mount your iphone to in order to make it less weird - or just download some screen-cap video software and do it that way.

once i get moved into my house and i can put my car in the garage and do that sort of thing i should be able to be more involved in this thread though

 02-27-2013 #69 DIYMA Addict Join Date: Nov 2010 Location: Sweden Age: 30 Posts: 4,701 Thanks: 0 Thanked 15 Times in 9 Posts Rep Power: 297 iTrader: (0) Re: The RTA Walkthrough and Usage thread. With Video. Anyone know if it's possible to set T/A with RoomEQ somehow? (Impulse response always end up at "0" ms.) Need to see the relative time. Haven't figured it out. Quite easy to do with HOLMimpulse or ARTA. # In a time of universal deceit - telling the truth is a revolutionary act # (George Orwell) - Build Thread 1, Mercedes-Benz E 320T (2000) - - Build Thread 2, VW Passat 1.8T (2000) -
02-27-2013   #70

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Re: The RTA Walkthrough and Usage thread. With Video.

Quote:
 Originally Posted by Hanatsu Anyone know if it's possible to set T/A with RoomEQ somehow? (Impulse response always end up at "0" ms.) Need to see the relative time. Haven't figured it out. Quite easy to do with HOLMimpulse or ARTA.
Not sure, but isn't this possible with a reference measurement at the same time? Ref comes first hardwired from pre-out or amp or pc and marks the 0.0ms, then the acoustical measurement comes later.

I know holm is inaccurate sometimes as you set to zero so a measurement with hardwired reference is most accurate in my opinion.

If you just mean with a click on a button : I don't know

Never say Ooops... Always say, Aahh Interesting....
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 02-27-2013 #71 DIYMA Novice Join Date: Apr 2008 Location: Leander, TX Posts: 312 Thanks: 0 Thanked 7 Times in 6 Posts Rep Power: 116 iTrader: (5) Re: The RTA Walkthrough and Usage thread. With Video. Well I did my first RTA using REW on the new system. I just got everything installed and running last weekend so have had no time to do any tuning but wanted to see what the response was from the initial setup of the 3sixty.3. Car: 2017 VW GTI SE, DSP: 3sixty.3, Tweets: Morel Piccolo, Midrange: Morel CDM-600, Midbass: Exodus Audio Anarchy, Sub: Morel Ultimo 12, Mid/Tweet: Rubicon 204, Midbass:Rubicon 702, Sub: Rubicon 1002[/FONT]
02-27-2013   #72

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Re: The RTA Walkthrough and Usage thread. With Video.

Quote:
 Originally Posted by Hanatsu Anyone know if it's possible to set T/A with RoomEQ somehow? (Impulse response always end up at "0" ms.) Need to see the relative time. Haven't figured it out. Quite easy to do with HOLMimpulse or ARTA.
Any chance of posting a how-to on doing it with ARTA? I tried it, but I always got an identical delay for every driver. Figured it was an issue with the hardware and/or how I set it up and couldn't find much help online. Went with a tape measure instead.

02-27-2013   #73

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Re: The RTA Walkthrough and Usage thread. With Video.

Quote:
 Originally Posted by Hanatsu Anyone know if it's possible to set T/A with RoomEQ somehow? (Impulse response always end up at "0" ms.) Need to see the relative time. Haven't figured it out. Quite easy to do with HOLMimpulse or ARTA.
Try this:
preferences -> analysis -> uncheck set t=0 at IR peak.

Agree, ARTA is easier
Love the grid in ARTA.

02-27-2013   #74

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Re: The RTA Walkthrough and Usage thread. With Video.

Quote:
 Originally Posted by charliekwin Any chance of posting a how-to on doing it with ARTA? I tried it, but I always got an identical delay for every driver. Figured it was an issue with the hardware and/or how I set it up and couldn't find much help online. Went with a tape measure instead.
If you see the same peak at around 5-6ms for all measurements, look for another peak after that one. Usually after 8ms or more. That's the signal from speaker.

See the pic:

Last edited by masswork; 02-27-2013 at 03:54 PM..

 02-27-2013 #75 Bikinpunk Join Date: Feb 2007 Location: North Alabama Age: 34 Posts: 17,152 Thanks: 45 Thanked 85 Times in 38 Posts Rep Power: 25981 iTrader: (94) You may also need to make sure you're doing a loopback measurement so your soundcard can reference the signal going out in time vs when it's actually sent out of the soundcard. This tells the system the internal delay. -- SQ is great, but sometimes nostalgia is greater. -- Follow my blog: http://medleysmusings.com/ Time Delay Calculator: http://tracerite.com/calc.html My 2006 Honda Civic LX Sedan Build Log

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