Rough tune on your EQ

**RedGTiVR6** · 06-08-2007, 10:25 AM

Originally Posted by archaic0

OK, so I was looking for a handheld meter with a better range, but they all top out at 130. I think I found that they do that because 130 is considered deafening. Am I on the right track there?

We have one here that goes over that, but it's also not a cheap hand held meter.

I found the frequency range of TrueRTA, but not the decibel range... anybody know?

Doesn't exist for software because it's limited to the hardware (mic).

As an example, Linkin Park's "What I've done" at volume level 25(out of 35) easily peaks the meter and isn't nearly loud enough to be painful. Conversation is out, that's for sure, but ears aren't bleeding and there's no distortion yet.

Just because you've maxed out a cheap hand held meter doesn't mean anything really.

To give you an example...with power classes being thrown out of USACi, SPL is a total of 130 dB for everyone.

Our car can hit 140s easily and that's a PURE SQ set-up. Not a street beater, not a mix and match, not a compromise.

Passing 30 on the dial starts to introduce distortion and starts to be uncomfortable. That's one thing I wanted to know the level of, but cannot find a meter that goes over 130.

A meter of 130 means you need to spend more money. THe materials that have to be used to achieve an accurate reading are more expensive.

Hince the reason that when in SPL, a member want's to try for a world record, they bring out a B&K meter. This meter is only brought to major events (regionals) and is only handled by the meters owner.

This isn't only to keep the standard, it's because this meter is incredibly expensive because of the level it can measure at and measure at accurately.

**archaic0** · 06-08-2007, 12:32 PM

I think I'm getting too far off track here really. My point with my setup is two fold. First I'm adding a sub and changing enclosures want to evaluate the change in a less subjective way than 'it sounds louder'. And second, I want to evaluate how my sound environment changes as I sound deaden the cab.

All I need to do really for the sub change measurement is pick a specific lower volume level and test all the tones as well as the same music before and after the change.

For the road noise, I'm not maxing the meter, so I'm ok there.

Does anyone know if there is a plugin for Street Deck or any other front ends that would give you at least a basic dB measurement inside the interface and touch screen usable?

I've bought TrueRTA now, but that interface is far from touch usable. Far too many tiny buttons. I've got a mouse hooked up, I'd just like to be able to check a quick dB level when curiosity hits.

In the absense of such a plugin, I guess I'll just keep the RS meter handy.

After I get the sound deadening done and the changes made to my components, then I'll break out TrueRTA and do a final tune of it all.

Thanks again for all your input guys!

**durwood** · 06-08-2007, 12:54 PM

You really won't get too much out of true rta if you are looking to investigate your sub change over. I think you will quickly find that it won't really show too much change due to something called cabin gain and the vehicles transfer function. There are plenty of other factors that it won't measure, such as phase, and transient response, midbass to sub integration, etc.

Also most mics are only rated up to 140db unless you go with specific SPL based mic. True RTA and the ECM mic are better for looking at overall frequency response over the entire spectrum. It's much better utilitzed with pink noise and not tones.

Good luck to you.

**RedGTiVR6** · 06-08-2007, 02:12 PM

if you want to know the difference, go to a SPL show before and after the change.

While the measurements won't be ideal because of different temperature, humidity, etc. It's not going to be any different than if you do it the way you're talking about.

There is no plug-in avaliable in any front end that I know of.

You are looking for such a specific application that I can't imagine anyone would spend the time coding a plug-in unless it was you.

One thing that you need to understand is that audio isn't always qualitative. You can't measure everything in audio. A lot of it simply how it sounds to your ears.

**archaic0** · 06-08-2007, 02:46 PM

Thanks for the input. I think I'm really a fish out of water with this technical measurment of a system. I can subjectively tune a system by ear like any layman, but when it comes to pro level stuff I'm just brushing the surface.

Right now I don't have a seperate EQ in my car, I'm just using the deck's built in adjustments. I should be able to listen to pink noise then in the car and get a graph with TrueRTA then of just how bad things are right now, right?

The goal is to get a smooth curve, right?

If there is anything you can tell me by looking at the following graphs? I'd apprecitate any input. Direct connected means I plugged the mic input directly into the headphone jack.

Thanks in advance!

BACKGROUND NOISE

PINK NOISE DIRECT CONNECTED

PINK NOISE IN AMBIENT MIC

QUICK SWEEP IN AMBIENT NOISE

QUICK SWEEP DIRECT CONNECTED

**archaic0** · 06-08-2007, 03:20 PM

I know a lot of it is subjective, I've just found these tools and so I'm exploring what all they can tell me. Either to validate what I already think I hear or just to watch things change as I make changes, it's just curiosity to me at this point.

As for the front end plugin, all I was after was a raw dB reading I guess, just to be able to go, "wow, the road noise on this road jumped up to 120dB!" Not really for tuning, but more just for the idle curiosity. TrueRTA can give me that easily, but it's just not very easy to use on a touch screen is all.

**archaic0** · 06-08-2007, 03:24 PM

I guess it might help if my laptop had a built-in mic. The spectrum changes when I use the generator so I thought it was picking up the ambient noise, but it must be listening internally to something because there's no mic pickup at all with a sound recorder recording.

**RedGTiVR6** · 06-08-2007, 03:46 PM

Nope - I think you need to read this thread before you go ANY further, there's a LOT of stuff you're missing here. Because of this you're not getting accurate readings:
http://www.avsforum.com/avs-vb/showthread.php?t=572477

**archaic0** · 06-08-2007, 04:15 PM

I went through that and I have a much better baseline now. All I'm lacking is a little instruction on what to do once I get in the car. As I said, I don't have an external EQ just yet so I only have 6 controls in the deck to work with... (bass freq, bass level, mid freq, mid level, treb freq, treb level) as well as some extra boost settings and response weight type settings.

Once I calibrate and have a nice pretty flat baseline in the car while it's silent, then when I play pink noise should I adjust the sound so that I have a smooth curve instead of spikes in certain places? Bring the spikes up to a lower level and bring the dips down to a higher level not to make them level, but just to make the line a smooth trip across the graph?

**RedGTiVR6** · 06-08-2007, 04:20 PM

yeup - just try and make it smooth as possible.

the thing is, you will have to go back and forth.

tune for a smooth curve then listen to it.

A smooth curve will not necessarially actually sound the best. this is why using RTA in judging for competition is a VERY controversial subject.

I wouldn't put too much faith in that curve. If you want to play with it just to learn about it, go right ahead. But I would tune by ear if I just wanted it to sound as good as possible for your situation.