Rew and car Hi-Fi. Is there a target curve?

[Bow_Wazoo]

Does the Qudelix 5k actually have time delay correction?

 

[Bow_Wazoo]

@Vacceo
According to several experts who install car hi-fi systems professionally, the issue of Sound insulation is particularly important in the BMW F30. There are also only 10cm speakers in the doors, which only operate at a maximum of 150Hz.
But I will still do something.

 

[Vacceo]

Any modern car has a serious lack of insulation. Fully covering it (that means disassembly, adding the layers and reassembly; that's why it's so expensive due to the amount of labor) will not just give you a great starting point for a acoustics; it will also reduce heat transfer, lower the noise floor and allow you a better result when EQing.

If you cannot afford such massive endeavour, consider at least doing the doors on every area, inner sheet to the outside, middle sheet and door panel.

 

[Bow_Wazoo]

I made a similar upgrade to the predecessor, the E90.
At the time, I used no additional insulation material. From a purely subjective point of view, I didn't notice anything that needed improvement. Nevertheless, I will do it "better" this time.

 

[MAB]

My first good car system was in a 1978 VW Rabbit diesel.
I reupholstered it with jute matt under the carpet, bitumen adhesive panels and jute in the door cavities, and replaced the door-card with upholstered wood panel (those old VW had simple flat door-cards.) It was the best audible improvement I made, especially since it improved the car when not listening.)

I ran the install shop at a car stereo store in the '80s. We tried to achieve flat response after correcting for the estimated road noise. I can honestly say we likely seldom achieved that, we had much less advanced measurement gear which really was most useful for determining defective drivers from the manufacturer prior to install, and blown drivers in a car prior to de-installation. Plus I knew nothing about acoustics having just started reading Speaker Builder, Loudspeaker Cookbook, Speakerlab and Radio Shack catalogs, etc. We also often got overruled by the customer, who were mostly Central Valley cruisers. I had a tri-amplified ADS system with Soundstream amps and crossovers, which was a departure from what I was typically installing. I just got the ADS tweeters out and measured them a few weeks ago (in free space with no baffle, and with a square sharp-edged baffle), they are still very competent:

I'd like to go back to the '80s with a laptop, USB mic interface, and REW.

I guess my point is, you should be able to select a response curve that matches your preference in your car. I bet that will change depending on if you are stationary or driving, and even how fast and the type of road surface. But at least you will be able to begin with reasonably well-integrated drivers based on measurements, and then choose a cabin-curve that sounds good across a range of conditions, and not fool yourself just because you are driving on a crummy road or in rain.

 

[Vacceo]

I made a similar upgrade to the predecessor, the E90.
At the time, I used no additional insulation material. From a purely subjective point of view, I didn't notice anything that needed improvement. Nevertheless, I will do it "better" this time.

Hi Fi aside, getting less heat and noise is totally worth it.

 

[Bow_Wazoo]

Yeah
I will never get used to the sound of the diesel engine.

 

[Bow_Wazoo]

Does the Qudelix 5k actually have time delay correction?

I wrote to Qudelix to ask if they could add the DTA function as an update. That would be ideal for me, as I need a headphone amp with DSP anyway.

In any case, my project is slowly taking shape.
The following components are installed so far:

Audison Prima APBMW K4E

Axton Bsub2

SPECTRON SP-N4207

Reckhorn ABX

 

[Bow_Wazoo]

View attachment 381715

... from Floyd Toole's book and this PDF;

https://www.linkwitzlab.com/Toole-Room%20calibration.pdf

JSmith

As soon as all components are installed and it is time for an FR measurement/correction, I will use the Olive and Welti target.

I just have the question of what an FR measurement should ideally look like?
If I follow the procedure used by Audiotec Fischer (video on page 1), that would mean:

1. pink noise as a test tone.

2. Driver stays in the csr and moves the mic between the left and right ear.

3. the left and right channels are measured separately, and a separate EQ profile is created for both channels.

 

[Bow_Wazoo]

I found an interesting article, about which measuring method has advantages and disadvantages

Microphone techniques in car cabin

miniDSP is a leading manufacturer of Digital Audio Signal Processors for the HomeTheater, Hifi, headphone and Automotive market. Join our large community of Audiophiles, Engineers and DIYers using our innovative products.

www.minidsp.com

 

[dmitrykos]

Can you please program a DSP app that works like Wavelet, on a higher level?

Additional app for me would be to much at this moment. But, could you give a link to what mentioned Wavelet app is doing?

 

[Bow_Wazoo]

it is a sound tuning app. Unfortunately time delay alignment is missing...

 

[Bow_Wazoo]

My conversion is slowly progressing.
A subwoofer and Bluetooth receiver are installed.

 

[Bow_Wazoo]

I discovered a test track, that is great to correcting the time delay.

It is always amazing, how huge the advantage of DTA in a car is!

 

[Bow_Wazoo]

My installation is complete.
After time delay, and frequency response correction, I can now say that the system sounds sensational.

I'm not finished with the settings yet, and still have a few questions. Among other things, I'm wondering how it is possible that I can measure such a high SPL below 35 Hz when my subwoofers (which are installed under the seats), have a frequency response starting at 35 Hz, according to the technical specifications?!

Left channel

 

[Palladium]

Do you mean a preference curve?
I cannot imagine a research with people going in and out of a car listening so to establish a solid percentage about it

Well, Samsung bought Harman for their car audio competency.

Of course there's research on it but I highly doubt anyone will be releasing that like Harman did for headphones (which weren't their main revenue stream).

 

[Bow_Wazoo]

Audiotec Fischer, for example, is clearly based on Harman.
That's why I did it too, as a test.
And I really like the result. The familiar tonality also seems to work in the car. What I find particularly worth mentioning is, that the FR correction has a very positive effect on the soundstage.

I haven't made any progress with the frequencies that I measured between 20-40Hz, and which shouldn't actually be there.
I can't explain a measurement error. Nevertheless, I will of course repeat the measurement.

 

[Bow_Wazoo]

It is done. Here the measured result.
L+R

Before/ after

My car hi-fi upgrade has been completed. The difference to the standard system is simply gigantic.