Distortion on low frequency

I'm trying to figure out what exactly causes the problem. Lets say on EQ, when I set the 50hz frquency to +6 (max), the speakers start to distort at no matter what volume. Setting the level to -3 (or something like that) will make the distortion go away. Now, this is also depends on the song played. Some distort at +6 (or whatever value), others don't.

Weak speakers or weak amp? What do you think?

Neither.  Probably distortion introduced by your EQ.

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EQ is built-in in the hu. It doesn't seem to me that it is the EQ itself that would mess up things.

Sure it is.  An EQ is usually the noisiest part of any system, even if it is built into the head.  Often it is the head unit itself (or more accurately the preamps in teh HU) that causes most of the distortion and noise heard in systems.  But anytime you turn any control to the max, no matter what it is, you operate at its limit and are much more likely to introduce noise, distortion and unacceptable sound.

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So how can this be fixed?

It can't.  If I'm right, it is simply a limitation of your equipment.  Don't turn it up to +6!

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DYohn is right on. This will usually happen one of 2 places: either the EQ runs out of headroom internally (the DSP runs out of digits to calcualte the math of the +6 boost) or the EQ's output is clipped when it hits the power amp in the head unit. Either way, short of buying new gear, the only way around it is to turn it down.

-dave

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Why would it run out of space to calculate the math? Doesn't it make the whole eq boost useless then?

And what will cause it to clip?

This EQ is actually of the Pioneer 8600 head unit. Retails for around $500. So I don't know why it would perform poorly. But that is also because I set loudness to on and bbe to +4. This adds to the distortion.

Turning it down works, but that means I sacrifice the features of the unit for normal, undistorted sound. This sucks :(

If you have the loudness on and bass boost up, then I am not at all surprised the EQ is overdriving the head unit pre-amp.  Just because a control goes to 10 (so to speak) does not mean the equipment will operate well there.  Adding all that signal processing takes you far, far away from "normal undistorted sound," especially with Pioneer equipment.  If you need or want more bass, you will need to do something other than try and squeeze it out of your head unit, such as add a subwoofer or use a larger amplifier.

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vbel]B wrote:

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t that is also because I set loudness to on and bbe to +4. This adds to the distortion.

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That's probably your problem. You're adding 2 things that crank the hell out of the low end. Loudness is usually between +6 and +10dB at 50Hz and the BBE bumps it another 4dB or so. When you crank 50Hz to +6dB, you all of a sudden have somewhere between +16 and +20dB of 50Hz boost dialed in. +20 is 10x the voltage, so if you started with 1Vrms sinewave, now you need 10Vrms, or about 14Vp-p, which is easily within the realm of clipping for signals inside (or even outside) the head unit. BBE also does some dynamic expansion, so that +4 number will vary by as much as 3dB depending on the signal, the BBE recovery, and the precise BBE algorithm that Pioneer licensed.

I bet if you kick off BBE or turn down your loudness a notch or two, you'll find you can get a little more boom before the splat.

It's not that you're being restricted from the "full potential" of your head unit, it's that you're asking it to do too much. Look at it this way: Inside the head unit, there is a fixed amount of gain that can be had before things clip. If you have the volume up a fair amount, it'll take off a fair portion of that. Add some BBE, a little more. Loudness, a big 'ol chunk. +6@50? Sorry, you're out of room.

If you need more bass, move the EQ to an outboard unit, ditch the BBE...soemthing. You're asking it to do too much. I figure Pioneer designed that head to have enough headroom to handle about 80% of what "everything on 11" would need. Frankly, that's pretty generous.

-dave

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This is not a sig. This is a duck. Quack.

Just because the feature is there does not mean that it has to be used. Dyohn is bang on with his advice (I was away on holidays guys  - Brooks & Dunn, Dwight Yoakam, The Mavericks and others - haha).

 What you are doing is simple. You need to think of the eq as a volume control. But first let's give you a better idea as to what is happening. You car has a redline and you know that as long as you stay below redline things are fine. Above redline, well bad things can happen. Now you need to think of your stereo having a redline that is controlled by two volume controls. If the eq is left alone you will notice that your main volume control can be turned up and there should be little to no distortion up to the redline (the point that distortion is highly noticeable). Now this master volume control is dependent on the secondary volume control, the eq (or bass / treble / boost settings). The more that these secondary controls are used in the + side adjustment, you will find that these two things will happen to the master volume control. One is that the redline will be much lower, two is that distortion is much more prevalent. This has nothing to do with how you want the system to sound, it has to do with the limitation of the equipment that you are using.

You asked about what causes it to clip. A signal must stay within a set limit, if it is asked to play outside of this limit it will clip the signal and introduce it as distortion to be amplified. When you look at todays music, I'm sure you have taken notice that some cd's tracks might have tons of bass and others do not. The first thing you do is adjust the bass settings to compensate. This can be infact part of how the material is recorded. If it recorded with a particularily heavy bass track and boosted considerably in the recording process, when the cd player is playing it back and you try to boost it some more, the signal is now hitting the redline and being clipped. In some cases it can be the cd you are playing, in others it can be that you are asking too much of the system. In all cases it will lead to the failure of a sub. Best to catch and understand it now before it is too late.

If you find the need for more bass (as indicated by the +6 setting on the eq), a larger amp, a larger sub, a different box or a combination of all 3 is in your future. I would also throw in an Eclipse cd player (couldnt resist guys - sorry dude).

Eq's can do a number of things, one is to solve a dedicated and identified problem that makes it necessary, the other thing is to screw things up, as it seems to be doing for you. Work the problem a step at a time and keep asking the questions.

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Thanks for the great (as usual) input Dave and Rob.  And Rob, how is good old Dwight these days?

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He sucked, I went and joined the other 30,000 people (probably more - no kidding) in the beer gardens and drank the rest of the night. Either I just was not into listening to him or the hot naked chicks in the beer garden were more interesting.

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Top Secret, I can tell you but then my wife will kill me.

Hmm, Dwight Yoakam's twangy old-school voice or hot naked chicks and beer?  Wow, a difficult choice, man.  I'm certainly hoping you made the right decision. 

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Boot Scootin' to the beer gardens...ahh the life...good to read your uncommon wit again, Rob!

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Wow, thanks everyone for their good input! It really makes sense what you all saying here. I guess I was expecting too much...

I played with the settings yesterday and the best I could do in terms of a compromise is turn off the loudness and leave the bbe at +4...I like it much more than loudness. And then I set the 50hz to somewhere between 0 and -3. But this is still pushing the limits...kind of. I bought a 75x4 amp that I should be getting next week, and I really hope that it will solve some or most of my problems. What do you guys think? Will I be able to set the 50hz a little higher with the more powerfull amp?

I'm just missing my bass here. The setup I'm talking about here is on my new car, a Honda Prelude 2000. For now I am still driving my old 89 4dr civic. All it has is a Pioneer head unit...not as fancy as my new Pioneer unit. It got stock front speakers (but taken from some other car...they're still not that great) and in the rear it has Pioneer 80w peak speakers. I'm not sure about the size of them, as I bought that car already with them in there...but probably a 5in something, or 6 inch..not sure. Anyway, what I'm trying to say is that I have way more bass in my civic than in prelude with better hu and better speakers! Isn't that weird? The sound may be not as bright and crisp in the civic, but there is much more bass in there. I have my loudness set to "hi" (this is the max setting). I set my bass to +6...it also has another bass setting which I'm not sure about what it is, but I set it to max at 160hz and it gives more bass this way. Sometimes I have to turn down the bass to +4...or +3 - this is usually as low as I would need to turn it down in order to get rid of the distortion. And if you're still not surprised, then I can set my volume to somewhere near 10-12 without hearing any distortion (of course I'd have to set the bass to +3 or +4)...and this is the max I would ever set it to...it is loud enough for me! Setting it any higher, will give me hearing problems for the next 1-2 hours...and I'm not joking. Outside, people can easily hear my music play with my windows rolled up. Some even asked me if I have a sub in there.


Can you explain me this phenomen? I don't get it...

IMO you said it right: you are expecting too much.  The system you describe is not designed to produce much bass and never will.  You are trying to squeeze blood from a stone by artificially enhancing the bass with your tone controls.  This will never sound very good.  If you want bass, you will have to buy a subwoofer. with its own amp.

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