New User! Please help with house curves.

[Bludsport]

Hi everyone!

I'm brand new here, and I'm obviously a novice and as such am a little confused and overwhelmed. It took me about a month, but I finally completed the install of a new sound system in my car. I think the hardest part is behind me, but I wish I knew then what I know now about speakers, frequencies, crossovers, etc. because I would have made better choices with regard to some of the components I chose.

Anyway, the system is up and running and I'd like to fine tune it. I have a Helix DSP V Eight amp that's driving mostly Focal K2 Power component speakers and a JL Audio 12" enclosed sub in the trunk powered by a 550w JBL mono amp. I've tried numerous time using the Helix software to try and auto equalize everything, but so far have had no success whatsoever. In fact, every time I use the Helix equalizer software, it's usually another step down in audio quality, so decided to try REW's new software along with a calibrated miniDSP Umik mic. I've only taken a few measurements so far, but already things are starting to look up, but I'm still not there. The system sounds good, well better than good, but not great and not as good as I'm sure it could.
Presently, it's very bright. There is plenty of low end thanks to the 12" sub, but the tinny brightness is killing me. I've watch a few tutorial videos on YouTube covering the REW and Helix software and uploaded a JBL overall house curve generated from "Jazzi's REW Tuning Companion" (see below), but for some reason, this house curve looks upside down and not at all like the images of the house curves in the tutorial videos.

JBL Overall House Curve
20 9
25 9
31 9
40 9
50 9
63 9
80 6.5
100 4.25
125 2
160 0
200 0
250 0
315 0
400 0
500 0
630 0
800 0
1000 0
1200 0
1600 0
2000 0
2500 0
3100 0
4000 -1
5000 -2
6300 -3
8000 -4
10000 -5
12000 -6
16000 -6
20000 -6

This is what it looks like in REW:

 

[Sonnie Parker]

Welcome to AV NIRVANA.

Every car is going to be different and this house curve will likely need adjusting. It is merely a starting point. Getting it precise likely won't be getting your sound in your particular car precise... so keep this in mind. A house curve is different for many people... some like a steeper house curve than others... it's all a matter of preference with trial and error.

First things first though... your graphs are not proper for reading your response.

The preferred axis for ALL subwoofer graphs is:

VERTICAL = 45dB-105dB
HORIZONTAL = 15Hz-200Hz.


The preferred axis for full range graphs is:

VERTICAL = 45dB-105dB
HORIZONTAL = 15Hz-25,000Hz.

These values are defaulted into REW, but can easily change and must be set back to these axis for posting graphs.

Set your graphs properly and then post your response. Or you can upload your .mdat file and we can post it for you.. assuming you have measured correctly.

 

[Bludsport]

Thanks for the welcome!

The image I posted today was taken from the non-Beta REW program I downloaded a few days ago. I installed JAVA and the new Beta version of REW this afternoon and after adjusting the preferred axis to the specs you posted, this is what the same house curve looks like now.

 

[Sonnie Parker]

This is still not correct. The graph you just posted has a vertical axis of -250 to 175 ... and a horizontal axis of 2Hz to 30kHz.

Adjust it to the axis points provided in my last post... or upload the .mdat and I can show you what it will look like.

 

[John Mulcahy]

Probably worth also attaching the file you are using for the house curve.

 

[Bludsport]

Thank you guys so much for taking the time to actually help me out with this. Getting support from car audio experts that specialize in DSP applications that I could actually understand from a layman's perspective, has been tough for me. That's no one's fault but my own, so I've been doing as much research as possible to help shorten the learning curve for me.

In an effort to keep you guys from too much guesswork, I thought it would be a good idea to give you some details with regard to the components I'm using:

Head Unit

• Pioneer AVIC 8200 NEX

Amplifier/Processors

• Helix DSP V Eight (8 channels, 80 W per @ 4 ohms w/2 line outs)
• JBL 5501 mono subwoofer amplifier (350 watts RMS x 1 at 4 ohms (550 watts RMS x 1 at 2 ohms)

L & R Front Speakers (Lower Doors)
Focal K-2 Power 130 KRC (coaxial)
Woofer: 5 1/8” (130 mm)
Voice coil: 1” (25 mm)
Magnet: 3 1/3” (85 mm)
Aramid fiber inverted dome
Separate crossover: 12 dB/oct (5.3 kHz)
Adjustable tweeter level: (0, -3, -6 dB)
Max. power: 140 W
Nom. power: 70 W
Sensitivity (2.83 V/1 m): 92 dB
Frequency response: 70 Hz – 20 kHz
Crossover Settings:
High Pass: 80Hz, Linkwitz -24dB/Oct
Low Pass: Bypassed,

L & R Front Speakers (Upper Doors)
Peerless by Tymphany NE65W-04 2" Full Range Woofer
Nominal Diameter: 2"
Power Handling (RMS): 20 Watts
Power Handling (max): 40 Watts
Impedance: 4 ohms
Frequency Response: 150 to 18,000 Hz
Sensitivity: 82.2 dB 1W/1m
Voice Coil Diameter: 1"
Crossover Settings:
High Pass: 511Hz, Linkwitz -24dB/Oct
Low Pass: 3,237Hz ,Linkwitz - 24dB/Oct

L & R Rear Speakers
Focal K-2 Power 100 KRS
100mm (4") Woofer
25mm (1") Voice coil
Magnet: Neodymium
TNK inverted dome tweeter
Separate crossover : 12/12dB/oct (3.5kHz)
Adjustable tweeter level: (0,-3,-6dB)
Max. power: 100W
Nom. power: 50W
Sensitivity (2,83V/1m): 90dB
Frequency response: 120Hz – 20kHz
Crossover Settings:
High Pass: 120Hz, Linkwitz -24dB/Oct
Low Pass: Bypassed

Subwoofer
J L Audio: TW3 12-inch Subwoofer Driver (400 W, dual 4 Ω voice coils) in sealed enclosure.
Crossover Settings:
High Pass: Bypassed
Low Pass: 60Hz, Linkwitz -24dB/Oct

I'm not too sure about the crossover settings I'm using, so any advice would be appreciated.
By sitting down and listing all this stuff, it seems the brightness is either caused by the crossover settings I'm using or the speakers I chose. The sub is more than adequate to cover the 20 to 60Hz range, but the Focal's can't really cover the mid-bass range, so I was thinking of swapping out the front lower door speakers with a pair Morel TiW 634Nd Titanium Series Hybrid 6" woofers with a a 40 to 4,500Hz range, and a nice pair of tweeters for the upper doors. This way, at least the front would be a fully active setup.

With that out of the way, I've also attached the .mdat files you requested below.

 

[Sonnie Parker]

Here's your measurement... doesn't look good at all really... and it way too low of a signal. You will need to follow the help files a bit closer to get your input level up to where it needs to be to measure the response.

I am not familiar with the Helix processor. Does it have a measurement microphone or headphone mics like the JBL MS-8... or are you pretty much on your own setting the filters?

 

[Bludsport]

This is an image of the curve again using the settings you posted:

 

[Sonnie Parker]

That's the house curve... and would probably sound good if you could get your response looking like that. What you measured above is way off.

 

[Bludsport]

My laptop plugs directly into the Helix via USB/Mini USB. The microphone is also plugged into the laptop with the same type USB. Helix offers a measurement microphone with a pink noise .wav file for about $500.00. I couldn't justify paying $500 to Helix for a $75 mic and a pink noise file so I got the Umik and use the pink noise .wav file for full range speakers I downloaded off the REW program.
Maybe it's the mic because I have the volume turned a little past 3/4. Anymore and my ears can't take it. The Umik is calibrated using the file I downloaded from their website they suggest using for a multi-channel system. I tried to calibrate the Umik on REW, but it states that calibrating a USB mic is not applicable.

 

[Sonnie Parker]

You need to use the measurement sweep provided with REW and try to get the mic centered where you head would normally be. You can raise the input level of the mic without increasing your volume on your headunit. The volume on the headunit shouldn't be over 75db loud anyway.

The UMIK is calibrated if you use the calibration file miniDSP provided you and load it into REW. You don't need to calibrate it again. All you will need to do is set the calibration levels.

You might want to read back thru the help files again. I think we would just be repeating what it states already.

 

[Bludsport]

Help files...yea, will do some more reading!

Thanks!

 

[John Mulcahy]

As you are using your own house curve file you should set LF Rise Slope and HF Fall Slope in REW's Target Settings to 0.

 

[Bludsport]

Thanks John. I had them set to zero when taking the measurements.

I'm a little confused with regard to setting levels. Since the Umik-1's calibration file is already uploaded into REW, is there any need for me to make any adjustments or set the levels using REW's sound card settings or is it simply a plug and play operation?

 

[John Mulcahy]

UMIK-1 is plug and play, REW will automatically set a suitable level for the volume control (to achieve unity gain in the mic) if the volume has been set too low and takes the volume setting into account when calculating the SPL so nothing you need to set up.

 

[Bludsport]

Thanks again!

I think I discovered the problem. I'm running apple boot-camp on my laptop, and I've always had problems getting Windows to work with the Apple/AMD audio software that boot-camp installed in Windows. I downloaded the OSX version of REW and everything seems to be fine now. The only glitch is that the Helix software only works in Windows, so to tune I'll have run back and forth between OSX and Windows, which will be worth it if I can ever get this thing tuned.

 

[ainuke]

Bludsport:

For what it's worth, diymobileaudio is an awesome resource for car tuning and equipment. The Helix is a favorite over there, and you'll likely find lots of members willing to help you along. There's a specific thread for REW with an awesome tutorial for maxing out its potential http://www.diymobileaudio.com/forum...first-timers-guide-measuring-your-system.html. There's a LOT of info regarding levels, setting your crossovers right, and EQ. It's a pretty involved process but great for learning.

I also have a great guide written by Andy Wehmeyer that uses a different philosophy (pink noise and RTA) that takes a fraction of the time and gets you 98% of the way there. (You'll end up tinkering your way around that last 2% forever, regardless of whose system you use, haha).
If you message me, I can send you the pdf.

-Erik

 

[Bludsport]

Bludsport:

For what it's worth, diymobileaudio is an awesome resource for car tuning and equipment. The Helix is a favorite over there, and you'll likely find lots of members willing to help you along. There's a specific thread for REW with an awesome tutorial for maxing out its potential http://www.diymobileaudio.com/forum...first-timers-guide-measuring-your-system.html. There's a LOT of info regarding levels, setting your crossovers right, and EQ. It's a pretty involved process but great for learning.

I also have a great guide written by Andy Wehmeyer that uses a different philosophy (pink noise and RTA) that takes a fraction of the time and gets you 98% of the way there. (You'll end up tinkering your way around that last 2% forever, regardless of whose system you use, haha).
If you message me, I can send you the pdf.

-Erik

Thanks Erik!

I'll shoot you an email.

 

[thexder]

Hi,
I imported the house curve as well. Looks alright.
Then I saw "add room curve" option which elevates low end drops high end.
What exactly is this used for?

 

[John Mulcahy]

The room curve controls provide a way of adjusting the target to accommodate low end boosts and high end rolloffs without loading a house curve file.

 

[thexder]

Okay, but I first saw that in 5.19 version which seem to use boost by default?
Only if I change the controls (LF/HF slope to 0) I get the same curve I see in today's version.
Which means 5.19 version is showing modified house curve by default? Am I seeing this correctly?

 

[John Mulcahy]

5.19 did not have an option to disable the room curve controls, 5.20 does.

 

[thexder]

I see. So my guess is correct that 5.19 did automatically show modified house curve?