# Tuning the Bitone.1 with an oscilloscope



## Nick337 (Nov 19, 2009)

Me and a friend were trying to use an oscilloscope to tune my entire system. I blew a speaker so now I think it would be a good time to use an oscilloscope to tune my car. I have 08 Acura TLS. my system consists of an Pioneer 4200-avh dvd, audison bitone.1, jl hd 600/4, jl 450/4, jl 1000/1, focal utopia be no.7 kit, focal k2p UV. I got a maximum undistorted output with the o-scope for the head unit at 35. Maximum volume is 40. 

Here comes the tricky part. How do use a o-scope to check the undistorted output of the bitone.1? The bitone.1 has a master level output along with single sliders to control the output per channel? 

Now to tune the bitone.1? would I have the master volume on the bitone.1 all the way up, and start scoping the individual channels with the sliders all the way down and then increase it to check the outputs? or is there a different way that I am supposed to check this? I searched quite a bit an haven't found an answer. Thanks to everyone that can help.

Nick


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## mattyjman (Aug 6, 2009)

if it were me, i'd have all the individual channels up and then slide the main up until/if there is clipping? the outputs for each channel should be the same. 

but i've never had the pleasure of using an o-scope, so it's just my 2 cents


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## Nick337 (Nov 19, 2009)

I thought all the outputs would be the same but using the o scope all the channel outputs are different depending on the slider position itself.


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## mattyjman (Aug 6, 2009)

they would be if they were in different positions... slide them all the way, maxed on all 8 channels, and each channel doesn't give you the same oscope reading?


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## Nick337 (Nov 19, 2009)

I didn't check it with all the sliders in the same position yet, but thats probably what i will have to do, thanks for your help buddy. just wanted to make sure that i'm doing it the proper way.


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## mattyjman (Aug 6, 2009)

i'm sure someone would have stopped me if i wasn't on the right path... good luck


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## Mr. Nice Guy (Jul 21, 2011)

cajunner said:


> don't be so sure someone is going to swoop in with a bucket full of clear up..
> 
> as far as my 2 cents, I'd say that unless you are looking for a fault condition, using an O-scope is unnecessary and following the manufacturer's directions for level settings should be all you need.
> 
> ...


I'm guessing you've never actually used an Oscope to set gains?


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## Mr. Nice Guy (Jul 21, 2011)

cajunner said:


> It's a big leap to assume something such as you have, Mr. Nice Guy.
> 
> To my knowledge, there's no car audio processor, amplifier, head unit, or speaker system on the market that requires the use of an oscilloscope to install properly.
> 
> ...





cajunner said:


> as far as my 2 cents, I'd say that unless you are looking for a fault condition, using an O-scope is unnecessary and following the manufacturer's directions for level settings should be all you need.
> 
> if using an O-scope held that much advantage to doing things the way the manual says, the manufacturer made a bad product, imho.



Setting gains with an Oscope is not a requirement, it's a tool that most people do not have available to use, but it's the absolute best tool available for the average consumer. Settings gains without an Oscope is guesswork, plain and simple. And for you to act like anyone who sets their gains with one has subpar speakers, is an even greater leap.


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## SoundChaser (Apr 3, 2009)

The reason an o’scope or DMM is not necessary to set gains is because music is very dynamic; levels are constantly changing. This coupled with not all music being recorded at the same level will only give you a good baseline when using a scope. Further adjustments may be necessary, especially if you have an active system.


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## SoundChaser (Apr 3, 2009)

Also, do you adjust for max output of your amp or max input to your speaker? And can you truly rely on manufacturer’s specs?


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## Mr. Nice Guy (Jul 21, 2011)

SoundChaser said:


> The reason an o’scope or DMM is not necessary to set gains is because music is very dynamic; levels are constantly changing. This coupled with not all music being recorded at the same level will only give you a good baseline when using a scope. Further adjustments may be necessary, especially if you have an active system.


You use an Oscope to set gains so that no matter how dynamic music may be, it will never send a clipped signal to your speakers. You don't use a -21db tone to set gains, you use a 0db tone, because no music you will ever play will exceed that. You'd know that if you had ever used one. You're just one of a thousand people here who knock something they don't understand and/or have never even tried, and believe that whatever equipment you have and what install methods you use are the best, because you've already installed it and you're too immature to accept the fact that there are better systems, tools, and installers out there. You, sir, are jelly. Deal with it, or get yourself an Oscope and see what you're missing.



SoundChaser said:


> Also, do you adjust for max output of your amp or max input to your speaker? And can you truly rely on manufacturer’s specs?


Both. If your speakers only handle 100W RMS, and your amp is capable of 130W RMS, you obviously set it to <100W RMS. If your speakers handle more than your amp output, you do the opposite. You would know this if you had ever used an Oscope.


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## getonerd (Jul 24, 2007)

I used to blow speaker amps head units all the time till I used to brag about it and the i got an o- scope and my amps and head unit and I was clipping bad


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## Mr. Nice Guy (Jul 21, 2011)

cajunner said:


> who said anything about speakers?


You did. You said that if an oscope is able to set gains better than what the manual recommends, which is nearly always by ear, that the product is defective.



cajunner said:


> if using an O-scope held that much advantage to doing things the way the manual says, the manufacturer made a bad product, imho.





cajunner said:


> the guy blew a speaker, I didn't say it was caused by not using a scope, and if you hold to the premise that a scope's use could have prevented that speaker from going out, I would have to agree only in the sense that you can see where clipping happens.
> 
> but following the manufacturer's recommendations on the amplifiers and preamps and source units, is good enough.
> 
> ...


Oscopes are readily available online for as low as $70 shipped. How is that not an accessible tool to consumers? And it IS guesswork, for reasons that you yourself stated. You can't always hear clipping, but with a scope, you will always see it. It removes all doubt, and all guesswork. And learning how to use one is a great way to acquire a new skill and experience with a tool that is very useful in many other fields other than car audio. I prefer to teach people to do things the right way, rather than telling them to do it the old fashioned way which in this case, involves a lot of risk to expensive equipment. Perpetuating myths and discouraging people from doing things the right way only perpetuates ignorance. So if I tell everyone I come across that asks how to set gains properly that they should use an oscope, then I am at no fault whatsoever for feeding them information that could cause damage. Some will take the advice and reap the benefits. Some will be stubborn or lazy and not try it. Some people can't afford $70, some people are set in their ways and blissfully ignorant, getting by doing things half-assed. But at least if they do blow something up, they only have themselves to blame because they were made aware of the best way to do something, in this case, setting gains. If they're terminally lazy/ignorant/stubborn, at this point they'll go out and get an oscope and learn how to use it.

So no matter how you look at it, me telling people the best way to set gains is by no means something you should discourage. You should be ashamed for telling me to not tell people that they need an oscope to properly set their gains. If you used one yourself, you'd realize how foolish your statements in this thread have been. I'm not interested in an argument, so I'll leave it at that.


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## SoundChaser (Apr 3, 2009)

Mr. Nice Guy said:


> You use an Oscope to set gains so that no matter how dynamic music may be, it will never send a clipped signal to your speakers. You don't use a -21db tone to set gains, you use a 0db tone, because no music you will ever play will exceed that. You'd know that if you had ever used one. You're just one of a thousand people here who knock something they don't understand and/or have never even tried, and believe that whatever equipment you have and what install methods you use are the best, because you've already installed it and you're too immature to accept the fact that there are better systems, tools, and installers out there. You, sir, are jelly. Deal with it, or get yourself an Oscope and see what you're missing.
> 
> 
> 
> Both. If your speakers only handle 100W RMS, and your amp is capable of 130W RMS, you obviously set it to <100W RMS. If your speakers handle more than your amp output, you do the opposite. You would know this if you had ever used an Oscope.


I don’t knock it, I’ve used this method as a baseline because my system gets very loud and I did not want to advertise to the neighborhood as to what I have. Of course with a 3 way active front I still had to tweak levels to optimize performance between speakers.

Manufacturers RMS specs. usually don’t mean diddly. I had an IDMAX that’s rated @ 1000W RMS in a sealed 1.25cf enclosure driven by a PDX1.1000(rated 1000watts). There were a couple of heavy songs that caused the sub to burp. After a couple of years the sub was replaced by an Esotar1200 which is rated @ 400W RMS. Same enclosure, same amp and the Esotar sub handled everything I threw at it, including the same songs the MAX had an issue with.


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## sqcomp (Sep 21, 2009)

I think we're doing a mock government imitation here.

As I read the manual for the Bit One (of which I'm doing the initial setup tonight on mine), it says to scope the source's outputs until just before clipping. I know that on my P-01, it will give an unclipped 5 Volt output at max with no boosts. On my last setup, we scoped at all output points (source and amps). This time I'll do the same except it'll be just to double check the Bit One's accuracy on it's clipping warnings. So really, as I read it, the only point one should even need to scope is the sources pre outs to get the best signal Voltage output before clipping that you can.

It is specified in the Bit One instructions to use a scope to measure the source's output Voltage. They ALSO go on to say that if one doesn't have a scope, then take the output up to 80% and let the Bit One go from there.

*One thing I do know is, you can absolutely set your gains more accurately (in terms of clipping versus non-clipping) to maximize Voltage output by using a scope versus your ear.*

Thoughts?


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## SoundChaser (Apr 3, 2009)

sqcomp said:


> *One thing I do know is, you can absolutely set your gains more accurately (in terms of clipping versus non-clipping) to maximize Voltage output by using a scope versus your ear.*
> 
> Thoughts?


Yes, but how does this really help with live music? Assuming you’re sending a 0db tone at ¾ volume from source to set gains. How are you going to know when you are surpassing that exact level with actual music?


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## sqcomp (Sep 21, 2009)

That's the thing...are you sending a 0 dB tone at 3/4 volume?

You know because the Bit One tells you that it's clipping.

Caj,

You're right. You don't NEED the scope. You can just get closer to the "edge" with one. 

Here's page 23 of the manual:

"2. How to calibrate the MASTER inputs levels

Follow the instructions as listed below:
- Insert the supplied disk:
• insert the “Setup CD” if the head unit you are using is an AUDIO CD Player

• insert the “TEST Signal DVD” if the head unit you are using is a Dolby Digital (AC3) “Audio Car Theatre 5.1” featuring analog outputs, or if it is an analog audio system featuring a central channel.

- Play track 1 (press Play);
- Set all tone controls to zero (0);
- Set balance and fader to centre (0);
- Adjust the head unit volume to the maximum undistorted output level.

Press BACK to go back to the previous step.

Press NEXT to go ahead with the set-up procedure.

Press CANCEL to exit the program.

Remark: calibration is absolutely required to adapt the Bit One inputs sensitivity to the signal coming from the source.

WARNING: the head-unit level must be elevated to the maximum undistorted level. If the head-unit level can not be tested in advance, bring the volume adjustment to approximately 80% of its maximum excursion. If the head-unit output level is set at a lower level the Bit One will produce a ground noise (hissing sound). Should such noise come from the Bit One during reproduction, you will have to repeat the calibration procedure this time at higher volume."

When it says "If the head-unit level can not be tested in advance, bring the volume adjustment to approximately 80% of its maximum excursion." That says to me scope the source's pre outs to determine signal Voltage. What does it say to you?


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## Nick337 (Nov 19, 2009)

ok i have used an oscope to adjust my gains on the bitone.1 and all of the amps. I had all the sliders on the bitone.1 at -20 output. and I started adjusting the gains on the amp with the oscope. its not clipping whatsoever. I been playing with this for a couple of hours. What I have also tried is the bitone.1 sliders all the way up without clipping and and adding jus a little bit of gain on the amps. Or does this way work better versus, using -20 output on all the sliders for the output of the bitone.1 and adjusting more gain on the amps? kinda puzzled here. Thanks guys for your help.


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## JariPozz (Jul 15, 2011)

Mr.Niceguy doesn't sound like a mr.niceguy.


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## Buzzman (Jul 26, 2007)

Let me make this easy for you. Here is what you do: Once you have run the I/O configuration wizard and set up your BitOne.1, set the master volume on the Bit One.1 to 0, and set all of the gain level sliders associated with the channels you are using to -3. This will allow you to send optimal output voltage to your amps without clipping the outputs of the BitOne.1. Make sure there is NO EQ turned on. Now, with your head unit turned to its maximum output level before clipping, and the BitOne.1 set up as I have recommended, use the scope at your amp to set the gains. Use test tones such as those found on Autosound 2000 CD104 (either -5db or -10db for your tweeters, midrange, and midbass, -10db or -15db for your sub) depending on your listening preferences, making sure you select the appropriate middle frequency within the frequency range covered by the particular amp whose gains you are setting. IMPORTANT: make sure that you *mute * *each *channel on the Bit One.1 that is not being used for the amp whose gains you are setting. Once you have set the gains for each amp, reduce the master volume level to a reasonable number, and then adjust the individual gain levels for each channel will now have to be adjusted to properly tune your system. In the event you find that a particular set of channels have to turned up higher than -3 in order to get the desired tonal balance, there is a little bit of extra headroom available unless the green LED signal comes on showing that you are clipping that channel. In such case, you will have to reduce the gain level for that channel until the light no longer flickers. Good luck.


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## Nick337 (Nov 19, 2009)

Buzzman said:


> Let me make this easy for you. Here is what you do: Once you have run the I/O configuration wizard and set up your BitOne.1, set the master volume on the Bit One.1 to 0, and set all of the gain level sliders associated with the channels you are using to -3. This will allow you to send optimal output voltage to your amps without clipping the outputs of the BitOne.1. Make sure there is NO EQ turned on. Now, with your head unit turned to its maximum output level before clipping, and the BitOne.1 set up as I have recommended, use the scope at your amp to set the gains. Use test tones such as those found on Autosound 2000 CD104 (either -5db or -10db for your tweeters, midrange, and midbass, -10db or -15db for your sub) depending on your listening preferences, making sure you select the appropriate middle frequency within the frequency range covered by the particular amp whose gains you are setting. IMPORTANT: make sure that you *mute * *each *channel on the Bit One.1 that is not being used for the amp whose gains you are setting. Once you have set the gains for each amp, reduce the master volume level to a reasonable number, and then adjust the individual gain levels for each channel will now have to be adjusted to properly tune your system. In the event you find that a particular set of channels have to turned up higher than -3 in order to get the desired tonal balance, there is a little bit of extra headroom available unless the green LED signal comes on showing that you are clipping that channel. In such case, you will have to reduce the gain level for that channel until the light no longer flickers. Good luck.


Thanks man, jus the answer that i was looking for. I did notice that if the you don't have all the output on each channel of the bitone.1 to fullrange, the slopes look a little fuzzy where it suppose to make a perfect sine wave, at the peaks of the sine wave is what im referring to. Doing it your way tells me that your gains on the amp will be minimally turned up if not any at all. Thanks so much man, for clearing this up for me. Like i searched long and hard, watched plenty of youtube videos, they never go into detail what i am asking about.


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## mitesh.soni (Aug 24, 2013)

Hi,

I'm the same situation, I know it may sound silly but there are so many volume controls to deal with to set the gain.

Here is my setup. CarPc DAC RCA to Master Low RCA Input Of Bit One.1. 

I've successfully done the configuration to set bit one sensitivity and set crossover points, I haven't touched anything else. 

I'm stuck on the bit on how to set the amp gain with regards to what Levels do I leave my sliders on? and master volume when setting amp gain, MAX? 3/4?. I've got the JL Audio HD600/4 (active) for Audison AV6.5 (70hz) Mids & AV1.1 Tweeters (2500hz) and HD750/1 for JL 10W6v2. I know the target voltage I need from their manuals.

Also which tracks do I need to play to set gains for tweeters, mids and sub? and which dB of track i.e 50hz 0dB for sub and is the track different for tweeter and mids? i've got the audison disc and autosound cd. Appreciate any help.


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## Buzzman (Jul 26, 2007)

mitesh.soni said:


> Hi,
> 
> I'm the same situation, I know it may sound silly but there are so many volume controls to deal with to set the gain.
> 
> ...


Here you go. Assuming you have properly run the I/O configuration, set all sliders for each output channel being used on your Bit One to -3db, and set the Master Volume to 0db. Set your subwoofer level to 0db. For audiophile playback use 5db overlap for your main speakers, and 10db overlap on your sub, on the Autosound CD. But, 10db overlap for your main speakers and 15db for your sub works for most people. Use the tone associated with a frequency in the *middle * (or as close to the middle as possible) of the frequency range that particular speaker is set up to play. Then, just adjust your gain levels to meet the specs JL Audio has recommended, or till just before you see the sine wave clip on your scope.

Good luck.


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## mitesh.soni (Aug 24, 2013)

Appreciate you helping me Buzzman, just few more things. 
my tweeters are set 2500hz butterworth with 18db slope, mids are band pass 60hz and 2500hz butterworth 12db slope and sub is 70hz 6db slope butterworth. 

Have I got this completely wrong, this is the first time I've gone active so sorry if I sound clueless. But it's amazing how much few weeks make.

Sorry I don't know what overlap means? Also after your gains are set do you ever move any channel sliders? Master volume etc? Or this the point in setting the amp gains?

Which tracks do you suggest.? Am I right in thinking it's say it's -15db 40hz for the sub and -10db 400hz for mids and -10db 4k for tweeters given the above freq. Of the Autosound CD and again thank you so much, hopefully I'll have a much better sound setup over this weekend


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## Buzzman (Jul 26, 2007)

mitesh.soni said:


> Appreciate you helping me Buzzman, just few more things.
> my tweeters are set 2500hz butterworth with 18db slope, mids are band pass 60hz and 2500hz butterworth 12db slope and sub is 70hz 6db slope butterworth.
> 
> Have I got this completely wrong, this is the first time I've gone active so sorry if I sound clueless. But it's amazing how much few weeks make.
> ...


Hi, I can't advise you whether the crossover frequencies and slopes you have selected are ideal or not because I haven't sat in your vehicle and listened to your system, and I do not know the specifications or limitations of your speakers. The manufacturer should be able to offer you some guidance. Ultimately, it's what sounds best in your car. That said, the settings you currently have appear reasonable, except I would start with a steeper slope on the sub (18 db or 24 db) so you don't have as much output into the lower midrange. 

With regard to overlap, the best thing you can do is listen to tracks 3 and 4 of the Autosound 2000 CD 104 on any cd player. Depending on your hearing capabilities, you will hear the difference between 5 db and 10 db of overlap. If you don't hear the difference, then go with 10 db. If you go with 5db, then use track 16 (1 kHz) for your midbass, track 18 (8 kHz for your tweeter) and track 19 (40 Hz) for your sub. If you go with 10 db, then use track 22 (1 kHz) for your midbass, track 24 (8 kHz for your tweeter) and track 25 (40 Hz) for your sub. *Important: make sure that all EQ on the Bit One is turned off or set flat during this process.*

Because the sliders on the Bit One were set to provide optimal output voltage to the amps for purposes of gain setting, once the gains have been set on your amps you will need to focus on setting the Bit One gains for listening to music in your car. I suggest lowering each of the gains to about -7db and listen to dynamic, full range music that will push your system with the Master Volume set somewhere around -15db, which should be fairly loud. If you adjust each slider up you will get to a level where the green light comes on, meaning that you are clipping the Bit One's outputs. So, slowly lower the slider until the light goes out. Then you will know the max setting for that particular channel. The sub channels will be a bit different because you may never cause the green light to come on because once your bass becomes too loud and boomy, you will know you need to dial it back to get greater clarity and coherence. Once you have this determined, move the Master Volume level to a position that plays music back at a comfortable level for you, then adjust the sliders for the various speaker sets until you get the proper tonal balance, output levels for each set of speakers, etc. And, you will use the Sub Output slider to further fine tune your bass. This step is where you find SPL meters and RTAs very helpful. 

Good luck.


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## mitesh.soni (Aug 24, 2013)

Thanks Buzzman, I think I understand now, your instructions are so much more clearer than the Manual. Will give it a go in morning, and after gains are set, I'll try and RTA car. I've got the ECM8000 mic. 

Are you running rca from your headunit to bit one or digital. I tried digital but it's too noisey in terms of hiss random clicks. And I can set bit rate etc from PC, even with lowest gains there is noise. 

So I've got Audioquest DragonFly DAC. Which is meant to be really good to get audio from your computer at highest quality.

Thanks


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## Buzzman (Jul 26, 2007)

mitesh.soni said:


> Thanks Buzzman, I think I understand now, your instructions are so much more clearer than the Manual. Will give it a go in morning, and after gains are set, I'll try and RTA car. I've got the ECM8000 mic.
> 
> Are you running rca from your headunit to bit one or digital. I tried digital but it's too noisey in terms of hiss random clicks. And I can set bit rate etc from PC, even with lowest gains there is noise.
> 
> ...


You are welcome. I am glad I could be helpful. I run both RCA and Digital, but listen through the digital connection. If you had noise with the digital connection with your Bit One the noise is entirely source related. You won't have it with some source units. I have posted about this in another thread. The solution is the Audison SFC. I have one in my set-up. Problem solved. Hopefully, you will get things dialed in tomorrow.


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## Coppertone (Oct 4, 2011)

Buzzman I hate to be a bother but I thought that you had a YouTube video of your car. For some odd reason I can't seem to find it with my Apple tablet. Am I mistaken about this ?


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## Buzzman (Jul 26, 2007)

Coppertone said:


> Buzzman I hate to be a bother but I thought that you had a YouTube video of your car. For some odd reason I can't seem to find it with my Apple tablet. Am I mistaken about this ?


Coppertone, no bother at all bro. Yes, there are two videos, shot by Ben Oh of Car Audio & Electronics Magazine back in 2010. The car has undergone significant changes since then, but here are the links to the videos:

SQ S500 - YouTube
Mercedes Benz S500 Trunk - YouTube

This will take you through the progression from the install showed in the videos to where I am now:

http://www.diymobileaudio.com/forum...uzzmans-03-mercedes-s500-system-overhaul.html


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## mitesh.soni (Aug 24, 2013)

I'll looking the SFC, so do you get no hissing. Like I get slight if engine is off even with analogue input but soon as you plug in optical or digital coaxial. The hissing/floor noise is high. 

Last question I think. What filter do I need to use as I have no idea. Butterworth or Riley? Is there any difference. And do I have to use the same filter ie butterworth for sub mid and tweeter. And again thank you so so much. I've been pulling my hair out trying to figure this out for months and without one day from you I think I finally get it.


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## Buzzman (Jul 26, 2007)

mitesh.soni said:


> I'll looking the SFC, so do you get no hissing. Like I get slight if engine is off even with analogue input but soon as you plug in optical or digital coaxial. The hissing/floor noise is high.
> 
> Last question I think. What filter do I need to use as I have no idea. Butterworth or Riley? Is there any difference. And do I have to use the same filter ie butterworth for sub mid and tweeter. And again thank you so so much. I've been pulling my hair out trying to figure this out for months and without one day from you I think I finally get it.


The SFC may or may not reduce background hiss. It will eliminate the clicks and pops you get when pausing or skipping a track while using the optical connection.

Regarding your crossover slope question, here is some reading that will be helpful to you:

http://www.bssaudio.com/product_downloads/App_Notes/Crossovers_Demysified.pdf

Filter & Crossover Types for Loudspeakers | Audioholics

Enjoy. 

As far as combining different filters goes, if you get the best result that way in YOUR car, do it.

Also, don't forget to experiment with the phase setting for each speaker on the Bit One to get optimal imaging. Your Audison test CD has phase testing tracks that are quite helpful in ascertaining the best setting for your car.


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## Coppertone (Oct 4, 2011)

Thank you very kindly for the link to your build, and to the video. It was truly inspirational and I learned a lot about higher end speakers due to it.


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## Buzzman (Jul 26, 2007)

Coppertone said:


> Thank you very kindly for the link to your build, and to the video. It was truly inspirational and I learned a lot about higher end speakers due to it.


You are welcome! And thank you for your interest.


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## Imagewerx (Nov 30, 2012)

Here's my 2p worth (about 3 cents in your money).Using a scope to set up a car audio system is something you do because you spend too much time on car audio forums and not enough time experimenting out there in the real world.
I've been installing and setting up car audio systems for about 25 years now,and only once in that time have I used a scope to do it with.My theory being that I listen to music with my ears and not a 2 dimensional screen on an electronic measuring device.The same applies for test tones,as I'm not in the habit of listening to pure sine waves while driving in my car,I set the system up using the music I like to listen to.The only difference the time I used the scope to set it up "properly" was that it wasn't loud enough for me.Turning all the gains up a bit by the same amount soon sorted that problem out.I got about 3 years VERY hard use out of that system and I didn't damage any drivers despite me not setting it up "properly" with a scope.
My belief still is that apart from the actual sound level we hear in the car,there is no audible or operational difference between a scoped and a non-scoped car audio system.
Pure tones make it VERY easy to hear small amounts of distortion that would never be audible when playing music that is made of a complex mixtures of harmonics with dozens of other random bits of ambience thrown in for good measure.From memory I think we need about 10% distortion to be audible when music is playing and less than 1% with pure test tones.So why waste ages trying to get rid of that last vestige of distortion while peering through bleary eyes at an oscilloscope screen when you can't hear it anyway?


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## Buzzman (Jul 26, 2007)

Imagewerx said:


> Here's my 2p worth (about 3 cents in your money).Using a scope to set up a car audio system is something you do because you spend too much time on car audio forums and not enough time experimenting out there in the real world.
> I've been installing and setting up car audio systems for about 25 years now,and only once in that time have I used a scope to do it with.My theory being that I listen to music with my ears and not a 2 dimensional screen on an electronic measuring device.The same applies for test tones,as I'm not in the habit of listening to pure sine waves while driving in my car,I set the system up using the music I like to listen to.The only difference the time I used the scope to set it up "properly" was that it wasn't loud enough for me.Turning all the gains up a bit by the same amount soon sorted that problem out.I got about 3 years VERY hard use out of that system and I didn't damage any drivers despite me not setting it up "properly" with a scope.
> My belief still is that apart from the actual sound level we hear in the car,there is no audible or operational difference between a scoped and a non-scoped car audio system.
> Pure tones make it VERY easy to hear small amounts of distortion that would never be audible when playing music that is made of a complex mixtures of harmonics with dozens of other random bits of ambience thrown in for good measure.From memory I think we need about 10% distortion to be audible when music is playing and less than 1% with pure test tones.So why waste ages trying to get rid of that last vestige of distortion while peering through bleary eyes at an oscilloscope screen when you can't hear it anyway?


To each his own I say. If you are happy with your way, who am I to tell you to do otherwise.


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## Imagewerx (Nov 30, 2012)

Buzzman said:


> To each his own I say. If you are happy with your way, who am I to tell you to do otherwise.


Ok,and sorry if it sounded as if I was telling anyone off,it wasn't intended that way.


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## subterFUSE (Sep 21, 2009)

Does anyone have a recommendation for a good, affordable o-scope to purchase?


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## nanohead (Oct 21, 2013)

subterFUSE said:


> Does anyone have a recommendation for a good, affordable o-scope to purchase?


Hantek has a decent PC USB scope for under $100 clams. The software is somewhat clunky, but it definitely works, and pretty well made for an el cheapo unit

I personally, only use a scope to figure out where my head unit clips, so I can set max volume at the head unit when I build up the system behind it. Good old amp gain settings I do by ear.


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## T3mpest (Dec 25, 2005)

Mr. Nice Guy said:


> You did. You said that if an oscope is able to set gains better than what the manual recommends, which is nearly always by ear, that the product is defective.
> 
> 
> 
> ...


LMFAO.. Arguing or not, there is no argument in what I'm going to point out next.. If you set gains with a 0db tone to "avoid clipping" on most music your getting maybe 1/4 to 1/2 of what your amp is rated at for most of the song. Even rap and heavily compressed music tends to be in the -3db range, it just stay there for most of the song.. If minor inaudible clipping isn't worth getting the other half of the power you paid for, that's on you..


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## T3mpest (Dec 25, 2005)

subterFUSE said:


> Does anyone have a recommendation for a good, affordable o-scope to purchase?


DSO nanoscope works fine, google it


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## win1 (Sep 27, 2008)

Sub'd


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## subterFUSE (Sep 21, 2009)

Buzzman said:


> Let me make this easy for you. Here is what you do: Once you have run the I/O configuration wizard and set up your BitOne.1, set the master volume on the Bit One.1 to 0, and set all of the gain level sliders associated with the channels you are using to -3. This will allow you to send optimal output voltage to your amps without clipping the outputs of the BitOne.1. Make sure there is NO EQ turned on. Now, with your head unit turned to its maximum output level before clipping, and the BitOne.1 set up as I have recommended, use the scope at your amp to set the gains. Use test tones such as those found on Autosound 2000 CD104 (either -5db or -10db for your tweeters, midrange, and midbass, -10db or -15db for your sub) depending on your listening preferences, making sure you select the appropriate middle frequency within the frequency range covered by the particular amp whose gains you are setting. IMPORTANT: make sure that you *mute * *each *channel on the Bit One.1 that is not being used for the amp whose gains you are setting. Once you have set the gains for each amp, reduce the master volume level to a reasonable number, and then adjust the individual gain levels for each channel will now have to be adjusted to properly tune your system. In the event you find that a particular set of channels have to turned up higher than -3 in order to get the desired tonal balance, there is a little bit of extra headroom available unless the green LED signal comes on showing that you are clipping that channel. In such case, you will have to reduce the gain level for that channel until the light no longer flickers. Good luck.


A lot of great info here, thanks.

Here is a follow-up question. In my car, I have kept the factory head unit because it's an Audi with MMI. The MMI system has an input level adjustment for the iPod connection that is separate from the volume control. How would you suggest finding the optimal setting for the iPod input level?

I have the Autosound 2000 discs. Should I rip them to iTunes and load them onto my iPod and run a setup like you describe above?


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## Imagewerx (Nov 30, 2012)

My next thought on this subject likens setting up a car audio system to cooking.When making something from raw ingredients,you wouldn't use an electronic "tasteometer" to make sure you've got the taste right would you? You'd use the very thing that will know if the taste is right when you serve the food-the human mouth of course.Actually there are fantastically complicated and expensive pieces of machinery that can do this,but you still end up with just a generic flavour with no real heart and soul in it.
Setting up your car sound system with an electronic measuring device for me will be like eating a ready made meal compared to one made by even a semi-competent chef.Yes it will be technically good with no VISIBLE clipping on the tasteometer,but it'll be like instant mashed potatoe and nowhere near as good as it could be if it was given the human touch using the greatest biological measuring device ever made-the human ears.

What I'd do is to sit in my car,play my favourite piece of music and tweak the hell out of it until my ears tell me it's right.20 minutes later I'd be happy that it sounded better than it did.Or I get my test tones and my 'scope,and 6 hours later I'd still be worrying if maybe I could get it JUST a little bit better,when it reality it sounded fine to start with.


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## subterFUSE (Sep 21, 2009)

Imagewerx said:


> My next thought on this subject likens setting up a car audio system to cooking.When making something from raw ingredients,you wouldn't use an electronic "tasteometer" to make sure you've got the taste right would you? You'd use the very thing that will know if the taste is right when you serve the food-the human mouth of course.Actually there are fantastically complicated and expensive pieces of machinery that can do this,but you still end up with just a generic flavour with no real heart and soul in it.
> Setting up your car sound system with an electronic measuring device for me will be like eating a ready made meal compared to one made by even a semi-competent chef.Yes it will be technically good with no VISIBLE clipping on the tasteometer,but it'll be like instant mashed potatoe and nowhere near as good as it could be if it was given the human touch using the greatest biological measuring device ever made-the human ears.
> 
> What I'd do is to sit in my car,play my favourite piece of music and tweak the hell out of it until my ears tell me it's right.20 minutes later I'd be happy that it sounded better than it did.Or I get my test tones and my 'scope,and 6 hours later I'd still be worrying if maybe I could get it JUST a little bit better,when it reality it sounded fine to start with.



Well, my take on this is that you are conflating setting the gains with tuning the system response.

To use your cooking analogy, setting gains it's like calibrating the temperature gauge on the oven. Tuning is like cooking the meal.

If the oven temperature is not calibrated correctly, then you don't know if your meal is getting cooked at the correct temperature. The recipe might call for 350 degrees, but the oven might be 375 or 400. You can burn dinner and not even realize it until it's too late. 

Likewise, if the gains are not set properly, tuning the system will be more difficult.

By setting the gains with an o-scope using a 0 dB test signal, we are certain the the amplifier is providing the maximum undistorted output. In other words, the oven temperature is exactly what it reads. This doesn't guarantee a good meal; you still have to cook it. But at least you know that the oven temp is accurate, which is helpful.

The tune of the system is much more subjective, just like cooking. I can fully see your point about going by ear in that regard.


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## T3mpest (Dec 25, 2005)

subterFUSE said:


> Well, my take on this is that you are conflating setting the gains with tuning the system response.
> 
> To use your cooking analogy, setting gains it's like calibrating the temperature gauge on the oven. Tuning is like cooking the meal.
> 
> ...


fixed that for you.. 0db test tone gain setting on the amplifier side is a joke.. Music rarely goes to 0db and you can't hear minor clipping, your just leaving a LOT of power on the table. Especially since to then level match you have to turn down the gains even more on some drivers.. If it's on a preamp side, sure turn it up as high as you can before you get it to clip to maximize S/N without clipping.. On the amp output side, set gains by ear


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## Buzzman (Jul 26, 2007)

subterFUSE said:


> . . . By setting the gains with an o-scope using a 0 dB test signal, we are certain the the amplifier is providing the maximum undistorted output. . . .





T3mpest said:


> . . . 0db test tone gain setting on the amplifier side is a joke. . . .


Hey Guys, why are you even debating setting gains with a 0 db tone? If you read my post # 32 you will see that the recommended method is to set gains using either 5 db or 10 db of gain overlap for the main speakers, with an additional 5 db of gain overlap for the sub, which renders your whole debate moot. 

As stated in Autosound 2000 CD104 - 

5 dB of gain overlap. The subjective loudness is 4.9 dB above [0 db]. The distortion is very minute (less than 0.3% averaged for the duration of the music) and is not audible. The peak voltage at the input of the amplifier was 1.8 times the amplifier's actual sensitivity for full output. 

10 dB of gain overlap. The subjective loudness is 9.4 dB above [0 db]. This amount of gain overlap is usually considered optimum. Peak distortion on most program material occurs for less than 3% of the program duration and is rarely audible to most listeners. The peak voltage at the input of the amplifier was 3.16 times the amplifier's actual sensitivity for full output. 



subterFUSE said:


> A lot of great info here, thanks.
> Here is a follow-up question. In my car, I have kept the factory head unit because it's an Audi with MMI. The MMI system has an input level adjustment for the iPod connection that is separate from the volume control. How would you suggest finding the optimal setting for the iPod input level?
> I have the Autosound 2000 discs. Should I rip them to iTunes and load them onto my iPod and run a setup like you describe above?


Hey, sorry I hadn’t responded to your post before now. I overlooked it. Are you running your iPod into the input section of your MMI system? Or are you connecting your iPod into the Aux input of your Bit One? I assume based on your question that it’s the former since that is the only reason to optimize the input level of your MMI system for the iPod. When running the I/O configuration with your Bit One you will be setting your MMI output level to the max level before clipping. The gain levels of your amps will be determined based on the gain relationship between your MMI and the Bit One. Optimizing the input level of the MMI system for your iPod will not affect that, so whether you set system gains using CD104 itself or a ripped version for Apple sources is of no consequence.


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## subterFUSE (Sep 21, 2009)

Buzzman said:


> Hey, sorry I hadn’t responded to your post before now. I overlooked it. Are you running your iPod into the input section of your MMI system? Or are you connecting your iPod into the Aux input of your Bit One?


I actually have both options available.

The MMI has the Audi Music Interface cable which connects my iPod/iPhone.
When the iPod is connected, the iPod's volume control is not functional. However, in the MMI software there is an input level adjustment.

When we checked the output from the Bose amplifier into my BitOne with an o-scope, we used the CD player. The Audi volume control could be turned up to 29 out of a possible 35 before we saw clipping on the scope.

I don't listen to music with the CD player, however. I use my iPod/iPhone.
Do you think I should rip the test track from the CD onto my iPhone and then try testing the Bose output with the o-scope while running the iPhone rather than a CD?




I also have an HRT iStreamer 12V connected to the BitOne AUX input.

I already checked the output voltage from the iStreamer. It outputs at 2.19V when I ran the AutoSound 2000 CD104 Track 7 via my iPhone. I matched that in the BitOne software.


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## subterFUSE (Sep 21, 2009)

Attempted to set levels today with my new oscilloscope.

Started with my midbass. They are crossed over from 50-800hz at 24 dB.
Used the 400hz tone, with -5 dB offset.

It worked very well on the scope. I got the gain dialed to exactly the point before the sine wave got clipped.


Next I tried to set my horns. However, when I connected the amp output for one of the horns to my oscilloscope, there must have been some interference because I could not get a stable sine wave to display. The wave display was very erratic and had many small jumps throughout. The oscilloscope was jumping between zoom levels due to the fluctuations in the waveform.

The same thing happened when I tried to do the subwoofers. Waveform unstable, with many small jumps.

Any idea what was causing the problems for my scope?


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## subterFUSE (Sep 21, 2009)

I went back for a second attempt and had better luck.

Got my subwoofer set with the -10dB overlap, and my midbass with -5 dB.

I was curious about whether to use -5 dB overlap for the horns, or maybe go with 0 dB because of their ultra-high efficiency? I know that wherever the gains end up I'll still be turning down the horns' levels in the BitOne.


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## Buzzman (Jul 26, 2007)

subterFUSE said:


> . . . I was curious about whether to use -5 dB overlap for the horns . . .


Yes. Speaker efficiency is not the issue here.


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## subterFUSE (Sep 21, 2009)

Which tracks from the AutoSound CDs would you recommend for o-scope testing the maximum undistorted volume level from the OEM amplifier? I think I am going to rerun my BitOne I/O Config Wizard.


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## Buzzman (Jul 26, 2007)

subterFUSE said:


> Which tracks from the AutoSound CDs would you recommend for o-scope testing the maximum undistorted volume level from the OEM amplifier? I think I am going to rerun my BitOne I/O Config Wizard.


Tracks 2 or 31.


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## subterFUSE (Sep 21, 2009)

Buzzman said:


> Tracks 2 or 31.


Those are music tracks.

Wouldn't I want to use a sine wave test signal for the o-scope?


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## Buzzman (Jul 26, 2007)

subterFUSE said:


> Those are music tracks.
> 
> Wouldn't I want to use a sine wave test signal for the o-scope?


CD 104 is the CD I have been referencing all along. Tracks and 2 and 31 are not music tracks.


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## subterFUSE (Sep 21, 2009)

Buzzman said:


> CD 104 is the CD I have been referencing all along. Tracks and 2 and 31 are not music tracks.


My apologies, I don't mean to sound argumentative... I'm just a bit confused.

Here is the CD 104 track list which I have. It says track 2 is the music reference for zero dB overlap. And tracks 31-35 are the same as 2-6, with levels adjusted to compensate for the loudness increase. I'm wondering if I have a bootleg copy that has the tracks out of order?

Anyway, should I use the tracks 7-12 to find my factory amp max undistorted level with my o-scope?


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## fcarpio (Apr 29, 2008)

Right, wrong or indiferent this is what I do:

First you need to be able to recognize a clipped signal from a non clipped signal.










1- Unplug all your speakers from the amps.

2- Create a few mono sine wave test tones that fall in the middle of the range of each driver you have. I usually create them at 0.5 amplitude, that is what works best for me. I use Audacity for this, it is free.

3- Connect the terminals of the oscilloscope to your headunit's output, start increasing the volume until you see clipping, then roll back a tad until clipping is gone. That will tell you the max volume you can use in your head unit without distortion. Measure all test tones and record your volume levels for each test. When done set the volume at the lowet level recorded. Leave the volume there for the rest of the setup.

4- Repeat step #3 for the processor's/EQ input gain. You will be measuring the outputs, try all test tones in their respective channel as some frequencies may clip earlier than others. 

5- For the amps is pretty much the same using all the test tones on their respective channel. Say, for the sub you will use a 45Hz tone, for the mids you will use a 200Hz tone, and so on. As long as the tone falls near the middle of the crossover points for each channel you are fine.

6- Hook up your speakers.

With this your gains are setup, *BUT your system is not balanced by any means.* An RTA is necessary to set the proper *output gains* for each channel from within your processor.

Works for me.

Someone please chime in if this can be made better.


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## Buzzman (Jul 26, 2007)

subterFUSE said:


> My apologies, I don't mean to sound argumentative... I'm just a bit confused.
> 
> Here is the CD 104 track list which I have. It says track 2 is the music reference for zero dB overlap. And tracks 31-35 are the same as 2-6, with levels adjusted to compensate for the loudness increase. I'm wondering if I have a bootleg copy that has the tracks out of order?
> 
> Anyway, should I use the tracks 7-12 to find my factory amp max undistorted level with my o-scope?


Oh, you are not being argumentative at all. That was my bad, I was going off of memory and at my age that's not always a good thing. :laugh: Use track 10 or 11 (or both for comparison purposes) to determine the volume level at which your HU clips the output signal.


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## subterFUSE (Sep 21, 2009)

Buzzman said:


> Oh, you are not being argumentative at all. That was my bad, I was going off of memory and at my age that's not always a good thing. :laugh: Use track 10 or 11 (or both for comparison purposes) to determine the volume level at which your HU clips the output signal.


OK cool, thanks!

My Bose factory stereo had 3-way active components up front, so I used all 6 of those amp outputs into my BitOne along with the subwoofer.
7 inputs on the BitOne used total.

I used tracks 7-11 on CD 104 to test those Bose outputs. Since they were active, I had to use different tracks on different outputs.
Interestingly, my OEM stereo did not clip any of the signals at any level.

So I ran my BitOne I/O config with the volume at full tilt.



I set my amp gains as follows:

Midbass was set with track 15. Crossed bandpass 70Hz - 900Hz @ 24 dB
Horns were set with track 16. Crossed Highpass 900Hz @ 24 dB

I tried to use tracks 17 & 18 to set my amp gains for the horns, but there was a lot of interference in the sine wave. It was causing my o-scope to jump all over the place and I couldn't tell when clipping was occurring. But the 1kHz tone worked alright, and the horns are crossed over below that point.

I set the subwoofer amp gain with track 19.
Sub is currently crossed over Bandpass 20Hz - 70Hz @ 24 dB slope.
Unfortunately, my o-scope could not display the full -10 dB overlap sine wave. The scope resolution would not zoom out far enough to display the full wave at clipping. I could tell that it wasn't clipping, but the scope just couldn't display the wave any larger. So I reduced the gain level to the point where I could just see the top of the wave. I knew I was leaving some headroom on the table, but figured I would play it safe. Besides, the sub definitely gets loud enough at the current setting.


On testing with some of my music, I had some clipping lights in the BitOne software on the midbass channels. So I turned them down a little bit.
I turned the horns down quite a bit more than the midbass because they are so loud. I'm assuming it's common to have to turn down the horns a lot due to their efficiency?


I also played with the staging setup CD from the AutoSound set. I tried reversing polarity on individual channels with the pink noise samples, listening for the best image location. I found a few channels gave better center imaging when they were reversed polarity.

I have not messed with the EQs yet. That is the part that really intimidates me.


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## Buzzman (Jul 26, 2007)

subterFUSE said:


> OK cool, thanks!
> 
> My Bose factory stereo had 3-way active components up front, so I used all 6 of those amp outputs into my BitOne along with the subwoofer.
> 7 inputs on the BitOne used total.
> ...


It appears that you are on the right track, given the issues you encountered with your scope. While it would have been better to use track 17 or 18 to set the gains on the amps powering your horns, it's not the end of the world. Like I mentioned in an earlier post, you will want to use some very dynamic music to make sure the gain levels on the respective channels in your Bit One are not so high that the Bit One's outputs are being clipped. In addition to monitoring for green lights flashing, you will need to adjust SPL levels between L+R channels and each set of speakers for proper tonal balance. The Radio Shack digital meter is a good, inexpensive tool to help you get things dialed in if you don't have a better quality SPL meter. Don't even worry about EQ until you have done this and run an RTA sweep to see what kind of FR curve you are getting.


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## subterFUSE (Sep 21, 2009)

What do you think could explain why I can't get a stable sine wave with tracks 17 or 18?

I was not running the engine during the tests.
I connected amp to my scope with a 12 AWG speaker wire and a BNC to binding post adapter Like this. This connection works well for test signals up to 1 kHz, but not above.

Maybe my scope cannot handle the higher frequencies?
It's a Vellemann HPS140i.

Perhaps I will try again using the scope's included test probe instead of the binding post adapter.


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## Buzzman (Jul 26, 2007)

subterFUSE said:


> What do you think could explain why I can't get a stable sine wave with tracks 17 or 18?
> 
> I was not running the engine during the tests.
> I connected amp to my scope with a 12 AWG speaker wire and a BNC to binding post adapter Like this. This connection works well for test signals up to 1 kHz, but not above.
> ...


That, I cannot answer. You should contact the Mfr and get their thoughts.


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## subterFUSE (Sep 21, 2009)

So I have finally tested my response on an RTA, and I definitely need to lower the volume on the horns a bit.

Right now, the horns have been set with a -5dB overlap tone with the BitOne channel level at -3dB. I then lowered the level in the BitOne to -9dB, but it still needs to be lower.

Would I be better served reducing the amplifier gain or by lowering the channel volume sliders in the BitOne SW even lower? Perhaps down to -11 or -12dB.

I guess I'm effectively asking if my S/N will be affected by running the BitOne channel volume lower while leaving the gains alone. Or is it better to keep the BitOne channel volume sliders up and reduce the amp gain?


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## Buzzman (Jul 26, 2007)

subterFUSE said:


> So I have finally tested my response on an RTA, and I definitely need to lower the volume on the horns a bit.
> 
> Right now, the horns have been set with a -5dB overlap tone with the BitOne channel level at -3dB. I then lowered the level in the BitOne to -9dB, but it still needs to be lower.
> 
> ...


Reduce the output level of your horns with the sliders for those channels on the Bit One.


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## mitesh.soni (Aug 24, 2013)

Hi Buzzman,

I've setup the gains etc on My Bitone.1.

I was wondering with regards to the RTA. I have the External Mic.

Now do I RTA each speaker with others muted? or do I do the whole lot together?

Also when I RTA do I move each EQ for each speaker or do I Link say both front MIDS then EQ them as One?

Do I aim for flat curve then adjust to my taste?

Thanks


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