[TrickyDIck]

Actually, an external soundcard is better the internal ones, especially in the laptops.

So, an USB powered external card is OK - that's what I'm using as the laptop one is very cheap

Could you revist your answer on this. I think the usb mic mate is a device which allows you to plug a microphone into a USB port, and has no interaction with the sound card at all. If using a microphone such as this, why would there be a need to calibrate a sound card?

TD

 

[TrickyDIck]

Tried to use TRUE RTA tonight.

Not sure what the heck I was doing.

I fiddled around a lot. printed a bunch of graphs, twiddled some more. Drank some beer, repeated steps 1-3...

Generated a smoothed curve, modified the EQ settings, and couldn't repeat the effort. Bagged it for the night, and had another beer, and wrote up this message.

Here was my penultimate smoothed Freq response curve. See attached.

Questions.

1. there are 20 memory slots on the program. If you run RTA and save, the single smoothed 1/6 Octave graph looked best, the rest seemed too un-real as if there was too much detail to be accurate. (peaks and valleys on graph too close and difference too much to be realistic - the averaged/smoothed corves look more "realistic". Is this the correct way to do RTA for tuning (using smoothed or averaged data)?

2. I was not sure which of the check marks to select under the RTA section. (there are 3 and all can be toggled independently - RTA bar mode, Relative Mode, and SPL mode.) Not sure what the "right" way to set them is.

3. input selection. Again here is a confusing thing. Many threads talk about using the MicMate and the Behringer ECM8000 which is what I've got. There is apparently NO interaction with the sound card whatsoever. The Micmate get registered as a USB audio device. Is it necessary to "calibrate" the micmate, and since it lacks the traditional input and output of a sound card, how to accomplish? Very confusing when you follow the threads and are new to this hobby.

4. Input selection L, R, L-R, L+R? WTF?

5. Input and output sampling frequency. I used 48khz. What's best?

6. Averaging? again WTF?

7. when playing pink noise through the head unit, is it best to optimize each speaker individually or all at once? My H701 allows Front & Rear Left and right + sub controls. I started with L+R not the individual L/R controls. Also, since I have a 3-way setup, there is only a single front control which for my setup would control the tweeter and the midrange both, while the rear channel controls the midbass.

8. After a few hours at piddling around, I was able to get a crappy looking curve with lots of peaks and valleys. I used the graphic EQ option, and got:

large peaks at 32,85, 375 Hz, with many smaller peaks (12 peaks total on the graph)
large valleys at 48, 315, 1437 with similar smaller valleys.

The biggest offenders weer already gained at the max + or - 9 dB.

Overall, on my scale which I think used the dBu (whatever that's supposed to be) value, the highest peak was at 85 (smoothed/averaged) -28 dBu. The lowest valley was at 1437 at -33.5 dBu.

Here is a graph I finagled into a SPL curve....

Comments? Feedback?

TD

 

[TrickyDIck]

Anybody.... Anybody....

Bueller.... Bueller....

 

[TrickyDIck]

Seems I once again answer my own post....

Done with tht RTA tuning. Sounds really good to my ear. Fairly flat, as close as I can get with this equipment (better than the last post).

Since I'm "done" with the stuff - at least for now, I may end up selling the equipment since its doubtful I'll ever use it again.

TD

 

[TrickyDIck]

I advise against selling it. You're never done.

Hmm...

I think you're right....

ears practically bleeding today... I think I need to readjust the tweeters... I think above 10k, probably don't want a flat curve if you like to listen loud.

Here are my "final" curves. Well after that I tweaked the gains a tiny bit on the tweets.. yellow one if the left/driver's side, purple is the passenger/right side. Yellow curve is a little "smoother"

TD

 

[TrickyDIck]

put it at 1/3dB resolution. Also, play the system. Note the changes that take place once both sides are playing together.

I'll try that.

Problem I am having now is balancing the system. Seems like at lower volumes (the kind that doesn't induce permanent hearing loss), the bass is underpowered. When I crank it up, the bass is there, but the tweeters become dominating. I turned down the tweeter gains and that helped this part of the problem.

Darn recordings are all over the board too, which doesn't help.

Thought about turning down the x-over gains and save them to the presets on the H701. One could be for more bass, one for less bass, and one in the middle or more balanced. I think the BASS COMP could basically accomplish the same thing, but it doesn't seem to. In order to do this, I'd have to turn down the other speakers and leave the mid-bass at +0dB since I don't think you can add +db in the crossover of the H701.

I could also crank up the midbass gains, but I think the speakers are going to hit their mechanical limits, before the amps peak out.

Any advice?

TD

 

[TrickyDIck]

Take a look at this thread. It talks about exactly what you're complaining about.
http://www.diymobileaudio.com/forum/showthread.php?t=49556&highlight=loudness+curve



That's not a bad idea. I do something similar, but I only have a couple settings; one for regular music and one for when I want to rock out. That setting has the sub crossed higher and at a higher level.

Is there an easy way to tune with A-weighting on TrueRTA? I don't think the program has any built in features to allow this.

I thought that a mic correction file could probably do the trick though?

TD

 

[TrickyDIck]

with trueRTA, not that I know of. I believe it's C-weighted by default and I've searched around, but have had no luck with being able to find a way to change it.

A mic correction file wouldn't really work, I don't think. It might be that the weighting varies with the level, too. If you calibrate, I'm thinking you'd be baselining the measurements and would always keep that curve (essentially).

So is there a way to do A-weighted levelling then? Obviously need to go back and read your post.

You used SmaartLive I think (PMed you about this).

TD

 

[TrickyDIck]

Smaartlive 5 can do A weighting plus C, X and Inverted X.

What the heck are X and inverted x??

PLan to save my current EQ as a no weighting (with True RTA), then try A weighting, and C weighting curves (with SmaartLive RTA).

Can tell you at high volumes, my current EQ leaves my ears bleeding. Either I don't have it turned up loud enough to equalize the frequencies to the C weighting spec, or I am going deaf. I think there may be NO weighting to the True RTA.

I should mention, that I made my curves for True RTA withe deck at 15 volume. Maybe I should crank it up???


As an aside, still have a ground loop noise problem...



TD

 

[TrickyDIck]

The thread is even on the same page of this sub-forum.

Tuning your car using a pc based measurement setup

I think I must be missing the boat here.


I put in a CD that has a pink noise track and put it on repeat mode. I've already positioned a mic in the listening position with cord runnning outside car. I sit outside and run the RTA program on a laptop.


From what Ive been reading, it seems like there MUST be a way that the PC is connected to their Head unit? I've got the W505/H701 and not sure how I'd do this.

ITs got to be something very obvious that I must be overlooking - conneting the sound card line-out to an aux-in for example?

TD

 

[TrickyDIck]

You have to use the program's generator and send the signal through your h/u and out through your system via the aux input on the h/u. you have to have a feedback setup, too. otherwise, there's nothing to reference itself to. Basically, loop your input/output. Instructions are on the first page of this thread, I'm pretty sure.

Yeah -
I tried making a loop-back circuit on my Vaio laptop (circa 2005) Hooked a 1/8" stereo mini plug to RCA into anothter similar cable connected with some barrel connectors to end up with a male - male 1/8" stereo mini-plug. Then I wiring Mic In to Headphones out. I know its not the same as line in and line out, but its all I've got. (At least until the M Audio Mobile Pre arrives - which appears to have both line in and line out, and also have 0 latency ... anyone want a good deal on a micMate?)

Could you refine this for me? Am I supposed to run BOTH a loop-back circuit from Line out -> Line in, as well as Line out -> HU Aux-In? This would require some Y-Splitters (I already have a mini-stereo splitter)? Its seeming this is what you've said. (attached photo of this steup)

So I tried following the recommendations for auto cal the line in and line out on the TrueRTA, but for the headphones/mic connectors, its not ideal. clipped waveforms like crazy on the OScope... I adjusted the volume settings in the windows control panel until there was no clipping then ran the autocal again. I must say I am a little bit leery about feeding this laptop headphone out into my Aux-In on the HU. I think I'll wait until the Moblie Pre comes in.

Also got WINMLS so I can follow along on the the other RTA thread. Seems like True RTA can do all the same stuff though.

I also think that I am going to use the A-weighting on Smaartlive v5.4 to re-tune (even though Chad in another thread advises against it, the car just doesn't sound right - too little low end). I may end up taking my existing EQ settings and average them with the re-tune EQ settings I get with the A-weighting, then saving these different settings into the H701 and see if I notice a difference with different listening levels. Incidentally, the Bass Comp feature on the H701 might accomplish the same thing as tuning to A-weighted-ness? Not sure, It does make for a nice way to compensate for recordings made with lower bass levels though..

TD

 

[TrickyDIck]

Well,

I tried calibrating my notebook soundcard. Hopeless. Going to wait till the Mobile Pre comes in to do any more. Just running the O-scope with a sine wave output and moving the mouse causes RFI on the trace. Tried running the system cal several times, and quick sweep curve looks like playing a game of artillery on one of those old PET computers -far from flat.

TD