posted
Well, I've pretty much finished up my frontstage, finally. 8's in the doors, Extremis in the kicks, mounted coax with a pair of ID tweeters.
I've never really had a great midbass sytem before, and that was pretty much my goal. Well, I got that, this front stage plays down to 63Hz (or 50Hz) with authority on all kinds of music. I don't think that I will ever be able to go back to a normal front stage, having the midbass up front is awesome.
So the problem is that I have a huge peak in the 150-200Hz region, due I believe to the Extremis drivers being in way to small of an enclosure. I cut fairly large holes in the back of the kicks and stuffed them, but it didn't really help much. I have -6dB of EQ there too, which helped a lot, but still not enough. It's painfully obvious when certain types of music are playing. I've considered buying a separate EQ and just EQing it down, but honestly I am not incredibly happy with the imagine height and soundstage (yes, I spent quite a few hours aiming...).
So here's my alternate plan. For awhile now I've been thinking about trying to put my mids and tweeters up on the dash. Now, before I start working on it, my main problem is going to be getting the mids (on the dash)to blend well with the midbass (in the kicks). I figure that I need the crossover point between the mids and midbass to be as low as possible, which brings me to my second problem: lack of space. With the mids between the dash and the pillars, I need to use small drivers. I mocked the setup up with a pair of Adire AV5's, and, though they fit, it was a bit obtrusive. So I've been thinking about trying out some of the 4" Aura drivers instead, perhaps a pair on both side, sealed up with a single small tweeter per side. I would REALLY like to use the Adire/CSS fullrange drivers...hmm.
So anyway, I would appreciate some feedback on the plan:
Adire Extremis in the kicks for midbass, playing up to about 125Hz, then hit with a 4th order crossover. I believe that with the EQ and the crossover, I can avoid the peak in the 200Hz range.
Aura 4" or Adire/CSS 4.5" x2 on the dash, playing from 125-probably 4Khz. Both of these drivers are fairly small, but have excelelnt displacement for their sizes. I'm hoping that with two sealed up per side, I can get good extension down to 125Hz without stressing them too much. I'm not worried about the top end extension...
A single small format tweet per side. Probably the ID's I already have, or something comparable.
Well, what do you think? Pros? Cons? Things I've obviously forgotten about?
Thanks a lot for the input, Ash
-------------------- ****************************** ****************************** Posts: 1130 | From: Los Angeles, CA | Registered: Aug 2001
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posted
haven't you been heavy into sq for years? i would have thought you had tried a strong mid bass up front system along time ago. it's awesome, isn't it. you'll find yourself turning your subs off and just listening to your front stage half the time. i think part of your problem is just the response gains produced by the location of the kicks. i just got off night shift and it's been awhile since i ventured into these (yeah, excuses already), but you might look into building a series notch filter. i know what i'm thinking, i just don't know if i'm naming it right. it's a passive device and will dip freq where you design it to. like a passive xover. help flatten out your peak. if you can get away with something on the dash, that'll work too. even some good 3's up there and run the 8's a little higher. you should still be able to get it dialed.
Posts: 540 | From: nor cal | Registered: Aug 2004
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posted
Well, a notch filter would probably help a lot, but off the top of my head I wonder how large the components are going to have to be at such a low frequency. It's definitely worth a look though, thanks for the suggestion. I think that this weekend I am going to take my kicks out, bring them inside, and listen to them in my living room. That should help determine whether the peak I'm getting is due in part to their placement.
I tool around the SQ area on here sometimes, but this is the first install I've done for myself in over 5 years, so I've really not had the opportunity to do a good system. And what I consider good SQ is probably not quite the same as the diehard SQ guys like EastCoast and Andy Jones, haha.
thanks for the response, Ash
-------------------- ****************************** ****************************** Posts: 1130 | From: Los Angeles, CA | Registered: Aug 2001
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I didn't have time to read your whole post, I'll get back to it later, but even with the kicks vented, they tend to be peaky anywhere from 130 all the way to 250. Nothing abnormal about that. You need a couple 30 band eq's Posts: 2276 | From: East | Registered: Jan 2003
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quote:Originally posted by Ash: And what I consider good SQ is probably not quite the same as the diehard SQ guys like EastCoast and Andy Jones, haha.
Winslow makes me look like a school girl just getting into car audio, that guy knows a lot-o-crap. I just help out where I can. Andy knows a lot too, but he's really just in it for the guys.
quote:Originally posted by Ash: And what I consider good SQ is probably not quite the same as the diehard SQ guys like EastCoast and Andy Jones, haha.
Winslow makes me look like a school girl just getting into car audio, that guy knows a lot-o-crap. I just help out where I can. Andy knows a lot too, but he's really just in it for the guys.
Anyways, generally the area that is going to drag your stage down is the octave above 125, depending on the vehicle, it can start as low as 100. The localization can also seemingly drag your stage in. No matter what you put in the kick, you are going to have that peaking problem. The odds of you running a driver in the kick from 125-200 w/out x-over/eq and not dragging your stage down are slim. Don't be afraid to try a gap. My car has a gap from 110 to 250! Taking the kicks out of that range will also change your imaging completely, so don't get too upset about your kicks yet.
An easy way (perhaps) around your problem is try crossing the kicks at 250, try different slopes but generally a steep one can be of assistance if you go the route I'm suggesting. Mount the midbass as high and forward in the doors as you possibly can, you can run them as a true dedicated midbass and not worry about the stage being dragged down or in, as they will be high and far to the sides. Your stage will be high and wide with little effort, provided your kicks aren't reflectively killing that illusion.
Crossing the kicks there will help you deal with that natural peak they have, you won't need as much EQ. And generally door's can peak from 50-80, if you build them right, you can lower that to where it won't be a big problem, then you can eq the rest out.
Time alignment would be very useful on the midbass in this situation. Had I to do my car over again, that is the change I would have made, mount the midbass higher in the door (the factory holes are generally as far forward as they can go) The countless hours of tuning, tweaking, hair pulling and beer drinking were due to finessing my way around the exact problem you are experiencing. There are a number of very shallow drivers that will do the trick.
Posts: 2276 | From: East | Registered: Jan 2003
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Welcome to cabin gain. That peak is probably an octave up from you sub's loudest frequency...all resonant frequencies of the car.
Tried any clay in the kicks? Maybe taming their resonance will help some.
But that problem you are having is a common one...last year when I had the 2 way front stage, I had a 14 dB peak in that area. Went back to a 3 way and it calmed it down a lot.
Me know a lot of crap? Crap is probably the right word there...lol.
-------------------- Team Image Dynamics/Zapco/Werewolf/JK Lab Team Kinetik Sick Bastard Audio SQ Who feels it knows it Posts: 7866 | From: Charlotte,NC USA | Registered: May 1999
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Damn, I knew I shouldn't have asked for help from a bunch of amateurs!
Well, that was all good information, and here's what I'm taking away from it:
1) There's a very good chance that the problem I'm having is related to cabin gain and not necessarily the kickpanel enclosure itself.
2) A way to fix this problem would be to either run only midbass in the kicks, below say 120Hz, or, if I have my mids in the kicks, to high-pass them at some frequency above the peaky area. Unfortunately, most of the midbass in my system comes from my kicks and not the doors, so I don't see high passing them at 250Hz...
Winslow, I'm wondering: If your problem was cabin gain, why did going from 2-way to 3-way change anything? Or did you notch or gap the frequency range where the problem was?
Thanks a lot fro writing in, I need to do digest this and make a plan, haha
Ash
-------------------- ****************************** ****************************** Posts: 1130 | From: Los Angeles, CA | Registered: Aug 2001
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posted
Well, it could be a couple of things all compounding each other.
One thing could be is the kicks are too small and not vented really well. This would cause a large peak in tha range.
Second is the enclosure could be very resonant, and you can really hear those colorations in the range you are talking about.
Third is abin gain of the car. Nearly every car has gain in that area.
I could underlap XO points in that area as well as getting the kicks breating better...also that extra 20 pounds of lead shot in each kick did wonders for resonance issues too .
-------------------- Team Image Dynamics/Zapco/Werewolf/JK Lab Team Kinetik Sick Bastard Audio SQ Who feels it knows it Posts: 7866 | From: Charlotte,NC USA | Registered: May 1999
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Though a small non-SPL section, we have some really great guys stopping in and posting.
-------------------- Team Image Dynamics/Zapco/Werewolf/JK Lab Team Kinetik Sick Bastard Audio SQ Who feels it knows it Posts: 7866 | From: Charlotte,NC USA | Registered: May 1999
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quote:Originally posted by Ash: 1) There's a very good chance that the problem I'm having is related to cabin gain and not necessarily the kickpanel enclosure itself.
Ash
Not necesarily, put a 2 way in the door and the majority of the problem will go away, move it to the kick and you will have peaking. Put a 3 way in the door w/the midbass firing into the footwell area and you may have a problem, add kicks playing in that boosted frequency range and you will have a lot of peaking. Its the combination of the 2, but there is little you can do about cabin gain, you need to work around it w/installation. Your kicks should be extremely open, breathing well into some chamber that is NOT in the cabin is optimal. I have never built a pair of kicks that did not need to be opened up. And they need to be HEAVY! Each of my kicks weighs 25 pounds. My kicks are crossed at 250 36bd/oct and the MB are crossed at 110, 24db/oct. I still have a 5db peak at 160 and 10db at 200.
Getting them to breath right and deadening the crap out of them is absolutely necesary, but will not get rid of the problem entirely. Getting the midbass location/firing position out of that footwell area will help as that footwell area aids its gain. Much like a downfiring sub in your living room, put it in the center and it will play at a certain volume, move it next to a wall and you can boost output by a couple db, put it in a corner and it can can climb a few more db. The physical gain properties of the room haven't changed, but the location of the sub will use it differently. You can do the same with the midbass. The kicks for imaging purposes need to stay where they are, many different variables apply, but if you have time alignment the midbass can be moved. As a side note, I've seen some under dash treatments cut the peaking a bit.
Posts: 2276 | From: East | Registered: Jan 2003
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