31 replies to this topic

[lupin]

So now that I'm going to get a little more serious with my build, I'm going to need some sort of RTA to do a little tuning.

Its been well over 10 years since I have used one, and that was the good old Coustic one that we all know and love.

I have a app for my iPhone (RTA Lite), but naturally I have no idea how good it will be, and it can only be used at low volumes, so it won't really allow for any cabin gain.

I have seen various software out there and DIY stuff all over the net, but my question is, is it any good. Something like what is on True audio.

I don't mind spending $100 or so on a mic and usb adapter, but if the app and phone will do as good a job then there is no point.

So does anyone have any experience with either method.

Edited by lupin, 03 October 2011 - 09:12 AM.

[~thematt~]

Forget an RTA. Tune properly first.

Download test frequencies at mono 1/3rd octaves and burn them onto CD. You can find them online everywhere.

When you insert the CD into your player, then play each track (and go back and forth between them) to make it 'audibly' the same volume between each frequency. Then use your left/right EQ to line up the 'centre' up through the frequencies.

Do this, and you'll be miles ahead of what an RTA can give you, off the bat.

[lupin]

Was thinking of doing it that way, as thats how I have done it in the past, only problem is my hearing is a little crap.

[SSSpoosah]

~thematt~, on 03 October 2011 - 09:49 AM, said:

Forget an RTA. Tune properly first.

Download test frequencies at mono 1/3rd octaves and burn them onto CD. You can find them online everywhere.

When you insert the CD into your player, then play each track (and go back and forth between them) to make it 'audibly' the same volume between each frequency. Then use your left/right EQ to line up the 'centre' up through the frequencies.

Do this, and you'll be miles ahead of what an RTA can give you, off the bat.

This is an awesome idea and not one I had really thought of.

I appreciate nice clean music but I must admit I cannot hear small steps in each 1/3 of an octave in normal music- at least in terms of it being an improvement in the overall mix or not

[Marc ♫]

~thematt~, on 03 October 2011 - 09:49 AM, said:

Forget an RTA. Tune properly first.

Download test frequencies at mono 1/3rd octaves and burn them onto CD. You can find them online everywhere.

When you insert the CD into your player, then play each track (and go back and forth between them) to make it 'audibly' the same volume between each frequency. Then use your left/right EQ to line up the 'centre' up through the frequencies.

Do this, and you'll be miles ahead of what an RTA can give you, off the bat.

Great advice, this is how all the big boys roll both here in Aus and overseas these days.

[Big_Valven]

I want to use an RTA to link how I am tuning to what we all know as theory, fletcher-munsen curves etc, but more as an educational thing than a tuning system.

There are Iphone apps out there that are quite good, I don't have an Iphone or experience with them but there is a ~$300 app which a certain speaker manufacturer here in Adelaide recommends very highly, time and frequency domain measurements (ie spectral analysis as well as waterfall plotting) etc. which can utilise a calibration curve on the inbuilt mic or even external ones.

[2LOUD2OLD]

~thematt~, on 03 October 2011 - 09:49 AM, said:

Forget an RTA. Tune properly first.

Download test frequencies at mono 1/3rd octaves and burn them onto CD. You can find them online everywhere.

When you insert the CD into your player, then play each track (and go back and forth between them) to make it 'audibly' the same volume between each frequency. Then use your left/right EQ to line up the 'centre' up through the frequencies.

Do this, and you'll be miles ahead of what an RTA can give you, off the bat.

link? i can't seem to find any, only one i could fins was one single continuous track, not very useful if wanting to go back and forth

i have been tuning via RTA lately, particularly useful for setting crossover points, tho would be keen to give this method a go to see what kind of results I can achieve

[~Spyne~]

use audacity to create the tones as individual tracks, james

[2LOUD2OLD]

~Spyne~, on 03 October 2011 - 06:29 PM, said:

use audacity to create the tones as individual tracks, james

thanks Adam,, never even heard of Audacity before, but just installed it, can just generate each tone and create my own disc, awesome! looks like I have a project to do tomorrow

[SSSpoosah]

Just downloaded it too

Looks very promising, thank you Adam

My system is tuned to an FM curve, and sounds good as it is

But It'd be nice to learn how to tune myself with the bit ten as well

[~thematt~]

lupin, on 03 October 2011 - 09:55 AM, said:

Was thinking of doing it that way, as thats how I have done it in the past, only problem is my hearing is a little crap.

In which case the result will align to your hearing. Using your ears is the best way to tune, first up. You should only follow up with measurement equipment once you know what you're doing.

Big_Valven, on 03 October 2011 - 06:14 PM, said:

I want to use an RTA to link how I am tuning to what we all know as theory, fletcher-munsen curves etc, but more as an educational thing than a tuning system.

There are Iphone apps out there that are quite good, I don't have an Iphone or experience with them but there is a ~$300 app which a certain speaker manufacturer here in Adelaide recommends very highly, time and frequency domain measurements (ie spectral analysis as well as waterfall plotting) etc. which can utilise a calibration curve on the inbuilt mic or even external ones.

Screw the iPhone apps. Invest in a cheap Mic setup with a laptop/computer (~$100), and you'll spend less, and get more. There are programs out there that send signals through an Aux cable, and then identify the response. Impulse responses, phase and power responses, waterfalls, RTA's at many different gated octaves, all packed into one nice little program.

iPhone apps are for boys, trying to do a mans job

[lupin]

~thematt~, on 04 October 2011 - 09:59 AM, said:

In which case the result will align to your hearing. Using your ears is the best way to tune, first up. You should only follow up with measurement equipment once you know what you're doing.

That's the plan, but if I do decide to step back into competition at some stage I'll need something better than my ears to set things.

Quote

Screw the iPhone apps. Invest in a cheap Mic setup with a laptop/computer (~$100), and you'll spend less, and get more. There are programs out there that send signals through an Aux cable, and then identify the response. Impulse responses, phase and power responses, waterfalls, RTA's at many different gated octaves, all packed into one nice little program.

iPhone apps are for boys, trying to do a mans job

Thats what I'm thinking of doing. I know there are a few people around town that would like to have a SPL meter to use as well so I may look into it a little more.

Yep my I phone app is all over the place, tested it on the home system and its nothing like I know it should look.

Might have to go with the old tone and Db meter to get a bass line and work from there.

[Pulse-R]

The iPod/phone RTA isn't really very good.

if you get an inexpensive measurement mic and USB adapter, that's fine.

I use SpectraRTA for measurements, but there are free ones as well.

[TMM]

Listening to fixed test tones (by ear or with an SPL meter) and adjusting your EQ accordingly isn't the best way of doing it, but it's better then nothing of course. If you only have a graphic EQ with a handful of bands don't get fooled into only sampling the frequencies you have on your EQ, because you need to consider what is between each of them also. E.g. You sample a 500hz tone and a 650hz tone (the center frequencies of two bands on your EQ), and find that there is a big peak at 650hz so you turn 650hz on your EQ right down. But there is also massive hole at 600hz which you don't know about (because you didn't sample 600hz), and you've just made it even deeper. Therefore you'd be better off just leaving the 650hz band alone. You can help this by sampling smaller frequency increments but it only goes so far and it is close to impossible to get an accurate idea of the frequency response at higher frequencies, because in a car there are peaks and holes all over the place.

Sweeps with a calibrated mic and an RTA is a far more accurate method and will avoid the above problem completely.

Edited by TMM, 09 October 2011 - 11:31 PM.

[lupin]

I'm going to have to go with the ears and tone method for now. Luckily I have a fairly broad selection of tones. I would like to buy a measurement mic but can't really find any cheap enough. Don't really want to spend 200 on a mic and adapter to use them a handful of times. Amazon have them cheap enough but won't ship to Australia. Local suppliers are more than double the price. I'll keep looking around but it's not looking good at the moment.