# Set gains with attenuated or non-attenuated test tones?



## JamesRC (Sep 18, 2017)

I've been reading through all of the system tuning material Andy's published lately through the Audiofrog site (PDF files at the bottom of the page here). 

On Pg 1 of the CD Liner Notes he recommends using test tones attenuated at -10dB to set levels/gains.

My current test tones are from JL. I wasn't sure if they were attenuated or not, so I pulled up their guide for setting levels/gains to check, available here. Their second bullet point says, "Do not use attenuated test tones (-10dB, -20dB, etc.)."

What do you all use and recommend? Attenuated? Non-attenuated? I'm planning to create a new batch of test tones and pink noise files using REW and Audacity and can do either.


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## 89grand (Nov 23, 2006)

Honestly, I've always set my gains by ear. There really isn't anything special about setting gains. I set mine so that I get the maximum undistorted volume before the source units maximum volume setting. 

Basically, I'd set the gain of the midbass to get the maximum output at say 25 on a headunit that goes up to 35, then simply adjust the sub/mid/tweeter gain to level match the midbass.


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## disconnected (May 10, 2017)

Non-attenuated, aka 0db 1khz and 50hz.


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## miniSQ (Aug 4, 2009)

i use 0db for tweeters...-5db for mids, and -10db for subs. Then i go back and adjust by ear. Don't do what i do.


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## JamesRC (Sep 18, 2017)

miniSQ said:


> i use 0db for tweeters...-5db for mids, and -10db for subs. Then i go back and adjust by ear. Don't do what i do.


LOL 

My amp has clipping indicators, so I just want to find the limits of the sub and mid channels. If I'm able to adjust my sub to match the target EQ curve in REW with my mids right below that clipping limit, and _without_ the sub channel clipping, that's the plan. If not, I'll keep my sub right below the limit, then adjust mids and tweets to the curve.


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## ChaseUTB (Mar 28, 2018)

JamesRC said:


> miniSQ said:
> 
> 
> > i use 0db for tweeters...-5db for mids, and -10db for subs. Then i go back and adjust by ear. Don't do what i do.<img src="http://www.diymobileaudio.com/forum/images/smilies/biggrin.gif" border="0" alt="" title="Big Grin" class="inlineimg" />
> ...


 Music is not test tones. Test tones which are steady / constant waves with no dynamics or fluctuations in the waveform. The test tones are RMS, average volume ( dbfs ).
The loudest songs/ re basses/ slowed music are usually peaking at -0 db ( over this is clipping, cant go higher than -0 dbfs digital full scale ) and have RMS volume of -5 (really loud)
The RMS volume corresponds to the - _db Of the tone. -5db tone is -5RMS. -0db tone is -0db RMS which is louder than -5 dB tone. 

So if you listen to rebass music for demo your SPL system use a 0db tone. Otherwise normal music is mastered around -5RMS dbfs to - 15RMS dbfs ( some streaming platforms ) and peaks ( not rms ) up to -0dbfs. 

Another reason ppl use 0 dB Rms tone is because this has the most voltage feeding the amp from the HU or DSP and ensures low gain or input sensitivity settings on amps to minimize noise. Then you can crank head unit full blast any damage anything. 

If using a -0db RMS tone You would set what’s called Input sensitivity overlap or gain overlap due to what I’m describing with the difference in tone vs music RMS volume. Gain overlap is where you will set the gains (input sensitivity) using 0 dB tone, then increase the input sensitivity ( or if amp labeled gain add/ turn up ) on the amp to better match the voltage input from the dsp or head unit. 

There are other ways to set it as well by voltage with dmm, oscope with waveform and voltage reading. All depends on the tools you have. Hope this helped you, you said audacity so I figured you understand the volume unit terms I used. Have a great day!

I use -3db tone or -5db cuz music playing at max volume out of the head unit still won’t be a steady voltage like you read with the scope or dmm won’t equal that voltage of the 0db sine unle


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## JamesRC (Sep 18, 2017)

Thanks. I ended up dragging about ten files into Audacity and zoomed in until I could see the wavelength. Most were between -10 and -5 dB, but one was full on at 0 dB. Based on that I decided to create my test tones at -5dB, figuring that I (1) the goal is to get the most signal in during playback without clipping, (2) I never play my system at full volume anyway, and (3) if I ever do, my bases will almost assuredly be covered.


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## ChaseUTB (Mar 28, 2018)

JamesRC said:


> Thanks. I ended up dragging about ten files into Audacity and zoomed in until I could see the wavelength. Most were between -10 and -5 dB, but one was full on at 0 dB. Based on that I decided to create my test tones at -5dB, figuring that I (1) the goal is to get the most signal in during playback without clipping, (2) I never play my system at full volume anyway, and (3) if I ever do, my bases will almost assuredly be covered.


Sounds good! I am sure you will like those settings. Even if you used a -0db tone, gain overlap would add another +5db lol so essentially it’s the same ( multiple ways to skin the cat ) 

I always like to use multiple tones ... I always see people use 1000 Hz and 40 Hz.. I like to use 40, 80, 500,1000,2000,5000 when I have the time. Otherwise the 40/1000 is used.


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