Tweeking my low end

ShockTherapy · Post by **ShockTherapy** » Mon Feb 22, 2010 4:48 pm

Hi everyone! Just installed my subs into my new enclosure and I need some help with adjusting things. I'm learning every day and one thing I just learned is that EQing your low end makes a huge difference. Here's a pic of what I'm running. The 2 Peerless XXLS 8ohm subs are in seperate 1.2cuft enclosures and being driven by the Arc Audio 2500CXL and filtered by the Audiocontrol EQL. I have everything set at flat right now. Where do I start?

I really want to put my back seat back in.

12voltjunky · Post by **12voltjunky** » Mon Feb 22, 2010 5:23 pm

I installed an Audio Control EQS in my wife's car.
It is totally overkill for her application...but I adjusted
the EQ for her sub channel based on my listening preferences.

I tend to like lots of bass so I started w the lowest freq on the EQS
with the volume about 2/3 up and tweaked it until I thought
it sounded good. Then I simply repeated this w the other freq

Maybe some of the guys with more knowledge can comment if you
give more specifics about your gain and crossover settings?

ShockTherapy · Post by **ShockTherapy** » Mon Feb 22, 2010 7:46 pm

12voltjunky wrote:I installed an Audio Control EQS in my wife's car.
It is totally overkill for her application...but I adjusted
the EQ for her sub channel based on my listening preferences.

I tend to like lots of bass so I started w the lowest freq on the EQS
with the volume about 2/3 up and tweaked it until I thought
it sounded good. Then I simply repeated this w the other freq

Maybe some of the guys with more knowledge can comment if you
give more specifics about your gain and crossover settings?

My gain was set with a multimeter before installing the EQL... now I'm going to have to repeat the process. The EQL has a 6 band 1/2 octave bass EQ... sounds cool if I knew how to adjust it!

Here's some features of the EQL for reference...

6 Band, 1/2 Octave Bass EQ
7 Band, 1 Octave Equalizer
Programmable Frequency Match (PFM) Subsonic Filter
Line and Speaker Level Inputs
Balanced Inputs
Input and Output Level Matching Controls

I have the crossover on the amp turned off and set to passive. the crossover on my head unit is also set that way. The EQL has an 18db crossover and subsonic filter... I'm using that to filter my low end. now if I could get this adjusted. I am wondering also where I set the gains on the eql when im setting the gains on the amp with the multimeter. Hopefully we can get some veterans to help me out.

Pillow · Post by **Pillow** » Mon Feb 22, 2010 7:55 pm

I am not help here but, that is a killer sub box!!!

Also what MBQ tweets are in those sets?

... Maybe I missed something, but where did the ZPAs go?

Looks great though! Keep it up.

ShockTherapy · Post by **ShockTherapy** » Mon Feb 22, 2010 9:31 pm

Pillow wrote:I am not help here but, that is a killer sub box!!!

Also what MBQ tweets are in those sets?

... Maybe I missed something, but where did the ZPAs go?

Looks great though! Keep it up.

Thanks! I had a guy on eBay out of Georgia build it for me. $200 shipped! double thick baffle, custom raised lettering and it's even coated with an extra 1/4" of fiberglass resin on the inside for stiffness. oh yeh... cross braced. As for the Quart tweeters they are the QTD-25 titanium tweeters which are part of the QSD-216 set installed in my truck. I will be replacing them with the alpine SPX17PRO components next week... the Quarts have begun to really hurt my ears.

When it comes to the ZPA amp I had I had to sell it. It wouldn't fit behind my seat without risking damaging it. It's sad because it absolutely amazed me in terms of SQ. The Arc Audio amp is wonderful... but I prefer the ZPA.

Pillow · Post by **Pillow** » Mon Feb 22, 2010 10:10 pm

Wow, that is a steal for that box! Nice score.

I just purchased an old school Q set (pre-Maxxsonics) and am looking forward to installing them. I used to hate MBQ tweets, but the older I get the better they sound... Then again I could be going deaf! The good part on the MBQ tweets is that they can get stupid loud and still sound crystal clear... So far I have not seen a silk that can do that. Also I think the "harshness" is more realistic, it took me a long time of going to live small venue concerts to figure that out though... Big sound stages at concerts are not accurate at all.

Enough ramble from me tonight

Post by **stipud** » Tue Feb 23, 2010 8:54 am

I don't recommend adjusting an EQ blindly. What you really need is an RTA (real time analyzer) which uses a microphone to measure the response of your system, so that you can see all the peaks and valleys of your response and compensate for them. Without being able to see the frequency response of your system, especially without having a flat reference system to compare with, you're much more likely to cause your system to sound more off than if you were to just leave it alone.

Unfortunately an RTA can be expensive, but you can build your own (there are many guides online, just google it). I used to use a Behringer ECM-5000 hooked up to my laptop through a small phantom power supply. It worked great. But now I run a standalone oldschool Alpine unit that lets you plug it into the cigarette lighter

Post by **smgreen20** » Tue Feb 23, 2010 6:03 pm

Yea, you'll need to "see" what you have freq wise. Start buy cutting those freqs that are the strongest. Find the medium in your peaks/valleys and adjust the cut accordingly, then follow up with what needs to be boosted. ALWAYS cut 1st, boost last.

You'll want (listener preference) to have roughly a 6 dB boost in your bass response. Your RTA curve should look like this. Follow the ^'s, I had to use _ because the space bar parts would disappear.

___________^^
________^^____^^
____^^___________^^
^^__________________^^^^^^^^^^^^^^^^^^^^^^^^^^^^

This type of response to some sounds bad, I've grown accustom to it.

Stryker · Post by **Stryker** » Wed Feb 24, 2010 8:29 am

smgreen20 wrote:Yea, you'll need to "see" what you have freq wise. Start buy cutting those freqs that are the strongest. Find the medium in your peaks/valleys and adjust the cut accordingly, then follow up with what needs to be boosted. ALWAYS cut 1st, boost last.

You'll want (listener preference) to have roughly a 6 dB boost in your bass response. Your RTA curve should look like this. Follow the ^'s, I had to use _ because the space bar parts would disappear.

___________^^
________^^____^^
____^^___________^^
^^__________________^^^^^^^^^^^^^^^^^^^^^^^^^^^^

This type of response to some sounds bad, I've grown accustom to it.

This is a good starting point for sure..... I usually adjust it then listen a couple of very familiar songs then go back and fine tune the gains and so on.....repeat......repeat again repeat a few more times, and then once I'M HAPPY with it, I leave it alone. Very few people have listened to my current set-up except a couple of friends and even then it was only for a minute or two. Kg and Stipud heard it when it was very weak up front, Now that I'm running 2 sets of RSD6.5's minus 2 tweets it's very different. Basically what I'm saying is unless you compete and are a total sound Q junkie adjust it how you like it and enjoy it, I'm a basshead and like my sound this way. Obviously you have some sense of musicality so trust your ears. As long as your not clipping your amps you can't really go wrong i would think.

Post by **Eric D** » Wed Feb 24, 2010 9:26 am

A 6db boost in bass response? Are you guys nuts?

I got the impression this was an SQ setup.

The cabin gain will naturally boost the hell out of the bass. If anything he would have to cut the bass to keep the system from being so overbearing.

I can see some boost way down low if he is missing bass there which is normal. This is assuming the box is sealed, not ported.

Post by **stipud** » Wed Feb 24, 2010 9:47 am

I would never recommend EQing a hump into your frequency response! EQ it flat, then use an LPL or Basscube to boost it from there. That way you can always go back to flat if you want to. If you bias it at the EQ you are stuck with it for all music, and IMO defeats the purpose of EQing in the first place.

I EQ my system flat with my LPL at the lowest volume. I usually leave it turned up about 10-20 degrees from there for a 3-6dB boost.

Stryker · Post by **Stryker** » Wed Feb 24, 2010 10:35 am

BAH.... I wasn't set on 6dB of boost.....

just a guideline. i like my car to sound like a club with tons of bottom end. I've never been about SQ more just decent sound. I do have the ability to adjust on the fly with my LPL and bass cube knobs. the OP was only looking for a little guidance....I'm no expert but i think my system sounds great for me. Maybe not but so what

it's only a car stereo.

Pillow · Post by **Pillow** » Wed Feb 24, 2010 11:00 am

You can do A LOT of "EQing" just with the proper box setup. Add in 6dB, 3dB, or flat. Tune the ports as low or high as you like.

... Personally I find the sealed boxes a real compromise in SQ. If you want really flat you need to go with a big box that is properly port tuned. Look at a sealed box plot and you will see that you are loosing a lot of low end notes. Also with a bigger box you do not need as much amp power to drive the speaker to maximum output.

For car use I do add 3dB though, but lower than the manufacturer suggests. Usually their guidelines do not match what I like to hear.

But sub boxes and sound really depend on what you like... I like SQ with exaggerated bass. Bass that you can feel in your chest.

But at the same time I would not call myself anything close to a boomer.

Post by **smgreen20** » Wed Feb 24, 2010 5:25 pm

If you EQ for a flat response in the sub range, you'll EQ the cabin gain out which to most of us will sound like poop. Remember, the RTA will show the response w/cabin gain, so if you EQ it flat, you'll have no more cabin gain.

For a true MECA/IASCA event you will want as flat as a response as you can get. That part is for certain.

But for a well rounded SQ sound, you'll want a hump in the bass region in the neighborhood of +6 dB.

Post by **ttocs** » Wed Feb 24, 2010 6:18 pm

interesting, I think this is the first time I have heard a ported box recomended for sq.

Post by **Eric D** » Wed Feb 24, 2010 7:55 pm

Well rounded SQ sound is not a +6db hump in the bass region. That is silly.

A gradually increasing slope into the bass region with +6db at 20Hz may be fine.

The only way a +6db hump in the bass region would be for SQ sound is if all you listen to is rap music.

ShockTherapy · Post by **ShockTherapy** » Thu Feb 25, 2010 6:43 am

Eric D wrote:Well rounded SQ sound is not a +6db hump in the bass region. That is silly.

A gradually increasing slope into the bass region with +6db at 20Hz may be fine.

The only way a +6db hump in the bass region would be for SQ sound is if all you listen to is rap music.

Thanks for all the advice everyone! I'm going to hold off on tuning right now. The enclosure and subs are going up for sale. I know! I just got them. I got a killer deal on 2 idq v3 tens and I'm building an enclosure at .9 cubes per side sealed. Once this is installed I will start tweeking. I will check back in a week or so and go from there.

I've been trying to EQ my Frontstage and have come up with so many different sounds. Is there a place to start there? The AVN7000 gives me full control over the frequencies. Here is a brochure on my unit. haha, "unit". anyways... They offer a dsp for this that would put this thing on tweeking steroids... read about halfway down the brochure. I wish i could find one used! that would be sweet. I'll be installing the new Alpine SPX17Pro components this weekend... I'll start tweeking then.

http://www.eclipse-web.com/us/webcata/a ... ochure.pdf

Pillow · Post by **Pillow** » Thu Feb 25, 2010 8:37 am

interesting, I think this is the first time I have heard a ported box recomended for sq.

Odd I know because it defies regular group think. But start running the charts in WinISD and it becomes quite clear that ported has a real advantage in tuning... Now to get below 20Hz you need a really large sealed box, but most people will not do that - and you still have long gradual roll off before hitting -3 dB. With ported you can go right up to 20 Hz flat and then nose dive the roll off.

And again with less power needed to reach full excursion.

... Most people do not want huge boxes in cars though, so the only easy way for SQ is sealed with polyfill. Small ported you really cannot tune the "gain" out of.

For home theater I love flat, but for music I have grown so accustomed to the "gain" it sounds hollow and unnatural without it. I listen to a lot of House music (most consider it Techno - but it isn't) at 130 BPM (beats per minute) and I like the punch. Granted it is a completely different kind of bass than rap.

ShockT, you are just about as bad as me at changing shit around!

Post by **stipud** » Thu Feb 25, 2010 10:36 am

Ported vs Sealed for SQ purposes depends completely on the driver. Some do well ported, others do well sealed. Typically subs with a higher frequency bias will do better in a ported box, which reinforces their low end and causes them to roll off much later. However, if you tune a low frequency biased woofer down low, then you just end up with a massively bloated bottom end.