DiyMobileAudio.com Car Stereo Forum banner
1 - 19 of 19 Posts

·
Registered
Joined
·
29 Posts
Discussion Starter · #1 ·
I recently aquired an IDmax12 v.4 and it is not performing like anyone on here describes. I need some real world personal experience with this driver. It is in a 1.7 cuft sealed box packed with blackhole stuff and being fed 600 watts at 2 ohms from a JL XD1000/5. All gains set correctly. All eq's flat. No bass boost. Sub bottoms out at 30 out of 35 on my head unit. Is the enclosure "shape" relevant to its performance? Currently the box is a somewhat shallow rectangle in order to achieve needed volume, look flush with back seats of suv, and conserve as much cargo space as possible.
 

·
Registered
Joined
·
9,244 Posts
Shape is irrelevant. Is the box properly sealed? A leaky enclosure can be noisy and reduce power handling. Is it a dual voice coil sub? Are you 100% sure it's wired properly? What kind of performance are you getting, is it just not as loud as you expected? Putting 600 watts to that sub should do a pretty good job, perhaps you are expecting too much from a single 12"?
 

·
Registered
Joined
·
4,081 Posts
The fact that it bottoms out at 30 of 35 is irrelevant.

I can set the gains to bottom out a sub at 10 of 35 on the head unit, or frankly any point. If that is your only issue, then turn the gain on the amp down a tiny bit.
 

·
Registered
Joined
·
29 Posts
Discussion Starter · #4 ·
Shape is irrelevant. Is the box properly sealed? A leaky enclosure can be noisy and reduce power handling. Is it a dual voice coil sub? Are you 100% sure it's wired properly? What kind of performance are you getting, is it just not as loud as you expected? Putting 600 watts to that sub should do a pretty good job, perhaps you are expecting too much from a single 12"?
The box is 100% sealed
Dual 4 ohm wired down to 2 ohms
The driver sounds very nice, even great at moderate levels, but at a little over 3/4 turned up ( 30 out of 35) on my head unit it begins to bottom out.
I'm not throwing crazy lows at it but I bought it because it can play lower than most.
I don't think I am expecting too much. I just don't see why this subwoofer is bottoming out or "reaching its mechanical limits" and distorting.
 

·
Registered
Joined
·
29 Posts
Discussion Starter · #5 ·
The fact that it bottoms out at 30 of 35 is irrelevant.

I can set the gains to bottom out a sub at 10 of 35 on the head unit, or frankly any point. If that is your only issue, then turn the gain on the amp down a tiny bit.
I am just using that as a perspective to reference how loud or level at which I am playing the subwoofer.
 

·
Registered
Joined
·
9,244 Posts
As Niebur3 pointed out, the number on the volume knob is irrelevant. If hte box is sealed properly, and the sub is wired properly, it's bottoming out because you're pushing it to it's max. You can apply a subsonic filter to help a bit. If that doesn't satisfy you, you can change the box, or add more displacement.
 

·
Registered
Joined
·
29 Posts
Discussion Starter · #7 ·
I really appreciate the input. Back to the drawing board. I just didn't think that 600 watts would push it to its max, but everything seems to point at that
 

·
Premium Member
Joined
·
1,165 Posts
How did you set your gains? Are you sure your amp isn't clipping?
 

·
Registered
Joined
·
29 Posts
Discussion Starter · #9 ·
How did you set your gains? Are you sure your amp isn't clipping?
Gains where set by shop that installed my amp and built my enclosure. I am not personally 100% sure the amp is not clipping because I unfortunately do not own an oscilloscope or a DD-1. The shop is an authorized retailer and installer for JL so assume they know the amps pretty well.
 

·
Registered
Joined
·
4,210 Posts
box is too big for it if trying to go for max output, scale the box down to 1.3 cuft and I'd bet the problem goes away.
 

·
Premium Member
Joined
·
1,165 Posts
Gains where set by shop that installed my amp and built my enclosure. I am not personally 100% sure the amp is not clipping because I unfortunately do not own an oscilloscope or a DD-1. The shop is an authorized retailer and installer for JL so assume they know the amps pretty well.
It really has more to do with your headunit than with the amp. Your h/u may start sending a clipped signal at 30/35, which is why you are getting distortion at that setting. You could check this fairly easily with a dmm and test tones. 1. Disconnect speakers from amp. 2. Set your h/u eq to flat and no bass boost. 3. Set h/u to 75%, so 26 or 27 in your case. Play a 50hz test tone at -10db or -5db. 4. Measure AC voltage from sub channel. (you would want ~34.5 volts----{sqrt(watts*ohms)}) 5. Adjust sub gain 6. Reconnect speakers and see if the problem still exists.

**if using this method, whatever volume setting you used to set gains with would be your Max volume. This would ensure you do not send the h/u into clipping. You would also want to go back and adjust gains on the other channels as well.**
 

·
Registered
Joined
·
29 Posts
Discussion Starter · #13 ·
It really has more to do with your headunit than with the amp. You h/u may start sending a clipped signal at 30/35, which is why you are getting distortion at that setting. You could check this fairly easily with a dmm and test tones. 1. Disconnect speakers from amp. 2. Set your h/u eq to flat and no bass boost. 3. Set h/u to 75%, so 26 or 27 in your case. Play a 50hz test tone at -10db or -5db. 4. Measure AC voltage from sub channel. (you would want ~34.5 volts----{sqrt(watts*ohms)}) 5. Adjust sub gain 6. Reconnect speakers and see if the problem still exists.

**if using this method, whatever volume setting you used to set gains with would be your Max volume. This would ensure you do not send the h/u into clipping. You would also want to go back and adjust gains on the other channels as well.**
Your right, I need to find out when the H/U is starting to clip. The hu is a kenwood excelon ddx491hd, I assumed it was better than that.
 

·
Registered
Joined
·
4,081 Posts
More than likely you need more power to be satisfied with the output or consider going ported to get increased output.
 

·
Registered
Joined
·
4,081 Posts
Oh, and check to see if any bass boost is on (either from the HU or the amp) and what the crossover point is set at. Also, is any EQ applied?
 

·
Registered
Joined
·
9,244 Posts
Here is the spec sheet for your sub.

http://www.imagedynamicsusa.net/specsheets/IDMAX12D4V4.pdf

As you can see, your enclosure is on the large side, and with the stuffing we'll just call it 1.8cf. Look at the frequency response chart in the pdf, that sub, in that enclosure is going to give a very flat response, which is ideal as long as you have the displacement to do that loud enough. The trade off for a nice, smooth frequency response is that you lose SPL. If you change the enclosure, then you'll be able to get significantly more output at certain frequencies, which you may find more satisfying.

It still sounds to me like you have your expectations too high. The sub is excellent, and the enclosure is great for a nice, flat response. But the combination is strictly designed around sound quality, and flat response, not SPL.
 

·
Registered
Joined
·
29 Posts
Discussion Starter · #18 ·
Here is the spec sheet for your sub.

http://www.imagedynamicsusa.net/specsheets/IDMAX12D4V4.pdf

As you can see, your enclosure is on the large side, and with the stuffing we'll just call it 1.8cf. Look at the frequency response chart in the pdf, that sub, in that enclosure is going to give a very flat response, which is ideal as long as you have the displacement to do that loud enough. The trade off for a nice, smooth frequency response is that you lose SPL. If you change the enclosure, then you'll be able to get significantly more output at certain frequencies, which you may find more satisfying.

It still sounds to me like you have your expectations too high. The sub is excellent, and the enclosure is great for a nice, flat response. But the combination is strictly designed around sound quality, and flat response, not SPL.
I had my head unit checked today with an o scope and it does not clip, even at full tilt. The gains where also checked and re-adjusted according to the o-scope.
I think you are right, I am expecting too much from this driver. Maybe I just need to get another one.....
 
1 - 19 of 19 Posts
Top