DSP Users - Spread your knowledge

[troutspinner]

I know DavidRam is getting into the DSP thing as well as I am close to pulling the trigger but I was hoping you guys who use them could help us newbies. I've done alot of searching and the info seems scattered and assumes some understanding that we just don't have. So let me ask some questions to see if I am on the right track with how to set one up.

Connect my ins and outs. For my example, stock HU, using Left and Right Fronts. Rears will run my rear doors off of stock HU power.

Configure the DSP to have 5 outs. 2 Mids, 2 Tweeters, 1 Sub. Take those outs into my amp's ins.

Configure gains both amp and DSP and then crossovers for each out. Those actual points should start around manufacturer specs and now I am lost!

Do you RTA with pink noise and then adjust crossover points and slopes to get nearest to flat?

If so, is that when you start EQ'ing to get closer to flat? Some DSP's have parametric EQ'ing, is that to give you finite control of those odd peaks and valleys?

If I am on the right track, listen to the system and then start adjusting the graphic EQ to your tastes? or do you adjust the parametric EQ? I think you see where I fell off here

Any help is greatly appreciated!

 

[lizardking]

I don't think there is any right or wrong answer when it comes to crossover points meaning that it will vary based on many factors. I tend to set my crossover points based on what response I get while watching my RTA and may change it many times while playing with the EQ. Looking for how the system transitions between each driver. I try to minimize the dips and peaks. Look for phasing issues. I will also eq separately by driver and left/right. For me, I start with the my subwoofer, mid bass, midrange and the tweeter last.

For example, when I'm using the EQ while measuring using the RTA playing pink noise, I will work the drivers independently of each other. Left mid bass by itself, make adjustments, Right mid bass, make adjustments. Measure and fine tune both together. I do this for each driver in my system. During these adjustments, I will stop and play tracks that I'm familiar with and are good for SQ turning.

As for EQ'ing for a flat response......I will EQ for my personal tastes while trying to keep the frequencies between 200-2.5khz flat. From there, I like it to roll-off gradually to 20khz at around 5-8db. I like a gradual roll-up at around 200hz to 125 at 6db to 20z.

 

[lizardking]

As for setting gains....I use to measure with a DMM, but the last few installs, I will adjust by ear. Make any final adjustments within the DSP. Setting the gain to minimize noise while maximizing output.

 

[lizardking]

Couple good threads..


Target Curve Comparison - Car Audio | DiyMobileAudio.com | Car Stereo Forum

Optimal RTA curve "template" - Car Audio | DiyMobileAudio.com | Car Stereo Forum

 

[lizardking]

Don't forget time alignment......IMHO, I try to minimize using time alignment and I'm always asking about how to minimize this. No way around this at least that I've found. I will set my time alignment at the same time I'm setting my crossover points and make adjustments as I go. I will use my IASCA disc for this. Many tracks on here that I use when I'm turning. I've always used it and familiar with it.

Sound Quality Reference CD

IASCA - Introduction "Ascent" (03:53)
IASCA - Left - Right Channel Verification (00:31)
IASCA - Phase Verfication (00:25)
IASCA - Instructions For Tonal Accuracy/Spectral Balance (00:20)
IASCA - Tonal Accuracy/Spectral Balance Evalution #1: "Throne Room & Title Ending" (01:21)
IASCA - Tonal Accuracy/Spectral Balance Evalution #2: "Superman - The Plant Krypton" (01:40)
IASCA - Tonal Accuracy/Spectral Balance Evalution #3: "Gavotte in D Minor" (01:37)
IASCA - Instructions For Staging Evaluation (00:26)
IASCA - Staging Evaluation #1: "Theme From Pink Panther" (01:49)
IASCA - Staging Evaluation #2: "Camarillo" (01:41)
IASCA - Staging Evaluation #3: "Fortune, Empress of the World" (01:40)
IASCA - Staging Evaluation #4: Technial Track "Left, Center, Right Narratives" (00:48)
IASCA - Instructions for Imaging Evaluation (00:36)
IASCA - Imaging Evaluation #1: "Blues Stay Away From Me" (01:52)
IASCA - Imaging Evaluation #2: "I Will Find You There (Jam" (01:45)
IASCA - Imaging Evaluation #3: "Too Close" (01:54)
IASCA - Imaging Evaluation #4: Technical track "Seven Drum Beats" (00:26)
IASCA - Explananation of Linearity Evaluation (00:21)
IASCA - Level Setting Instructions for Track 20 (00:23)
IASCA - Level Setting Track for Linearity Evaluation (00:20)
IASCA - Low Volume Linearity Evaluation: (74dB average / 81dB peak SPL) (00:53)
IASCA - Moderate Volume Linearity Evaluation: (86dB average / 93dB peak SPL) (00:53)
IASCA - High Volume Linearity Evaluation: (98dB average / 105dB peak SPL) (00:53)
IASCA - Noise Evaluation Instructions: (00:29)
IASCA - Noise Evaluation: "A la Vaise" (01:06)
IASCA - "WARNING !!! REDUCE VOLUME" (00:19)
IASCA - Zero Bits: Total Silence (00:40)
IASCA - RTA TEST TRACK: Stereo Pink Noise (Uncorrelated) (02:07)
IASCA - UNLIMITED SPL INSTRUCTIONS (00:08)
IASCA - SPL Track: "Toccata" (Don Dorsey - Beginning) (00:41)
IASCA - SPL Track: "Toccata" (Don Dorsey - Ending) (00:42)
IASCA - Sine Sweep - (20 Hz to 55 Hz) (00:39)
IASCA - Sine Sweep - (30 Hz to 65 Hz) (00:39)
IASCA - Sine Sweep - (40 Hz to 75 Hz) (00:39)
IASCA - Sine Sweep Test Tone (Sweep Stepped from 1 to 200 Hz rising in freq. @ 1 Hz Per Sec.) (03:15)
IASCA - "Thank you for competing in IASCA" (00:10)
IASCA - John Williams: "Throme Room & Title Ending" (04:42)
IASCA - Harry James: "Blues Stay Away From Me" (03:59)
IASCA - Michael Ruff: "I Will Find You There" (06:50)
IASCA - Clair Mario: "Too Close" (04:44)
IASCA - Harry James: "Sandford & Son" (02:10)
IASCA - Don Dorsey: "Toccata" (03:08)

 

[DavidRam]

Hey, great thread! You are definitely way ahead of me because I was already lost half way through the original post...

Subscribed...

 

[troutspinner]

Thank you very much lizardking. That is some great info and guidance.

I didn't even think about EQ'ing each speaker separately, now that is smart and takes some guess work out of it.

I've read that target curve thread before. I actually achieved the JBL curve on my last install and but knew nothing about why I did it other than what sounded good to my ears. This of course was using an iPhone RTA. This time around I will have to get a good mic for the computer.

The disc you pointed out for is intriguing, does it come with a guide or is it a "figure it out" type of thing?

Can you clear up Graphic EQ and Parametric EQ for me? Where / How / Why would I use parametric over GEQ? This will also help me in a decision to get the DEQ-8 or the DSP-88R.

Thanks again!

 

[lizardking]

Yes, the ISACA disc comes with a pamphlet guide that is used for judging. It gives you some guidance as to what you should hear.

Difference is the parametric gives you more control over the bandwidth that allows you adjust specific frequencies along with gain. The graphic is more of "broad stroke" over several bands. The graphic eq is easier to use and requires less skill. Graphic eq works in most applications.

I use the audiotools app for my iPhone along with the Dayton mini-mic. Works just fine!

 

[lizardking]

Download the software from Helix and PPI and play around on your computer. You can see what i mean when you start to mess with the equalization and how it affect bands around it.

 

[lizardking]

For example, If I had a peak at 4000hz, but I didn't want to affect the frequencies around it. I would use the "gain" to bring it down and the bandwidth "Q" to narrow it to the 4000hz best I could.

 

[troutspinner]

lizardking. Thanks again. I did download the software previously but the parametric part was what was confusing to me. After your reply and after watching some videos, I went back in and I do believe I am starting to understand.

I have another thread asking which DSP over at DIYMA and Maximilliano pointed me to a couple of great links that helped too.

One of his links inadvertently led me to this 4 part video series explaining equalizers on youtube that may be of interest to newbies https://www.youtube.com/watch?v=o6sqfYBIYVg

And here is a link Maximilliano gave me to a thread by ErinH at DIYMA about the Essentials of Sound Quality The Essentials of Sound Quality IMHO - Car Audio | DiyMobileAudio.com | Car Stereo Forum

In layman terms, I believe parametric is to EQ the same way slope is to a crossover. It gives finite control on the shape of it. Further, it tells me to go for the DEQ-8 over the DSP-88R as I know I want that control.

 

[troutspinner]

Alright, DEQ-8 ordered.....but I have my worries. Newegg has it as a closeout for $250 shipped. Kind of a low price, I am wondering if there is a mistake somewhere. Oh well, I have CC protection.

 

[lizardking]

Good to hear that you're starting to understand it. It can be mind boggling and I've been after a long long long time. Parametric can be overwhelming at first. If you just sit and play with it and don't worry about tuning, it will become easier to understand. Once you're ready, you can see the results as you make live adjustments. To me SQ is subjective in terms of the listener. We all hear things different. Regardless of what the RTA says, you will find yourself adjusting the sound to what you determine "sounds good".

To me, I like to use recordings that I know have been recorded exceptionally well. I also like to use a nice set of high quality headphones, because that is the sound I'm after in my vehicle.

My advice is simply take a good track, listen to it with a set of high quality headphones and try to get the same sound in your vehicle or as close as you can. Ever notice that a good set of high quality headphones playing a good track doesn't get tired? Sounds good, doesn't wear you out from listening fatigue? The other thing to remember is take plenty of breaks while tuning. You're ears will start to trick you after just 15-20 minutes. Keep tuning to 10 minute sessions and take plenty of breaks in between.

 

[lizardking]

List of tracks that I use and know well are

Rush - Tom Sawyer
Dire Straits - Money for Nothing ( pretty much the entire CD "Bothers in Arms"
Pink Floyd - Dark Side of the Moon and the The Wall
Eagles - Hotel California and the live version from "Hell Freezes Over"
Sarah McLachlan - Mirrorball
Alice in Chains - Unplugged ( Nutshell and Brother )
Telefon Tel Aviv - Maps of what is Effortless, specifically Bubble and Spike

 

[BradKnob]

Alright, DEQ-8 ordered.....but I have my worries. Newegg has it as a closeout for $250 shipped. Kind of a low price, I am wondering if there is a mistake somewhere. Oh well, I have CC protection.

crap, howd I miss this? seems lizrdking covered everything. Its all kind of mind boggling at first, but once you have the program in front of you and youre sitting in the truck listening it all starts to come together. good luck

 

[troutspinner]

crap, howd I miss this? seems lizrdking covered everything. Its all kind of mind boggling at first, but once you have the program in front of you and youre sitting in the truck listening it all starts to come together. good luck

I was SO on the edge of pulling the trigger on the DEQ or DSP-88R but I just needed this last piece of knowledge to decide on one or the other.

I've been wanting to try a DSP setup for about 3 years so pulling the trigger finally feels good and this should be fun.

 

[lizardking]

Big T over at DIY can get them really cheap as well.

 

[BradKnob]

I was SO on the edge of pulling the trigger on the DEQ or DSP-88R but I just needed this last piece of knowledge to decide on one or the other.



I've been wanting to try a DSP setup for about 3 years so pulling the trigger finally feels good and this should be fun.

Awesome. After having one, I'll never run dsp less again. Amazing what difference they make. Mine should be back this Tuesday, I'm ready to get back to real sound again. Anxious to hear what you think of it

 

[DavidRam]

Alright, DEQ-8 ordered.....but I have my worries. Newegg has it as a closeout for $250 shipped. Kind of a low price, I am wondering if there is a mistake somewhere. Oh well, I have CC protection.

Big-T sells them for $275 shipped, you got a great deal. Alright man, we are in this together at the same time.
If I procrastinate a little I'll be able to learn from you, lol!

 

[DavidRam]

lizardking thanks for ALL the info... I am gonna need to take my time and read through it again.