[ctuna]

If you are expecting specific numbers you would have to find
somebody that has the exact same setup as you and has done
the experiments. In general the underseats are mid bass drivers
and you want them to carry some of the mid bass the tiny 4 inch
door speakers don't carry. That range is around 150 to 200.
You will have to listen to it to find your ideal range.
Or if you want to get scientific get a microphone and one of the real
time frequency analysis apps for your phone or pc.

[kaigoss69]

Originally Posted by lendlease

Okay well what do you think my settings for the amp should be if I have the
Logic 7 set currently? I have the 4" mids, tweeters, and the 8" underseats.
The mids and tweeters are ran together on the first two channels. And the
underseats are ran by themselves on the other two channels.

Comes down to how low the L7 mids can play. I think 200hz is as low as I would set it, based on some experimentation I did way back when.

[lendlease]

Originally Posted by kaigoss69

Comes down to how low the L7 mids can play. I think 200hz is as low as I would set it, based on some experimentation I did way back when.

Okay great.

So if I am correct you can't really set an exact 200hz on the amp since it's a
dial, but I can like ballpark it right? And if I set the 200hz highpass for the
mids (front channel) I should set 200hz lowpass for the underseats (rear
channel)?

And then what would you say to put the gain at? I believe the range is about
8v to .2v or something like that. I currently have the gain for the front
channels at about a quarter turn(?) and the rear channels at about a half
turn(?).

I read a thread a while back that on this amp this gain should be set at the
minimum (8v) because of the high output of the HU. But when the rear
channel is set to that the underseats are barely audible so I've changed it.
I will have to revisist that thread and re-read it since it was like 23 pages
long and I only remember some things.

[kaigoss69]

Originally Posted by lendlease

Okay great.

So if I am correct you can't really set an exact 200hz on the amp since it's a
dial, but I can like ballpark it right? And if I set the 200hz highpass for the
mids (front channel) I should set 200hz lowpass for the underseats (rear
channel)?

And then what would you say to put the gain at? I believe the range is about
8v to .2v or something like that. I currently have the gain for the front
channels at about a quarter turn(?) and the rear channels at about a half
turn(?).

I read a thread a while back that on this amp this gain should be set at the
minimum (8v) because of the high output of the HU. But when the rear
channel is set to that the underseats are barely audible so I've changed it.
I will have to revisist that thread and re-read it since it was like 23 pages
long and I only remember some things.

Forget the manual. Do this. Turn the amp gains all the way down. Turn volume knob on head unit all the way up to the point where you're sure it is at maximum volume. Now count the clicks down to zero volume. Multiply by 0.8 and set volume there. Now turn gain from midrange/tweeters up until the volume is the highest you would ever want (keep in mind you could be overloading the speakers, so be a bit conservative). Now reduce the HU volume, play some good bass-heavy content, and increase the gain for the understates until you think there is a good balance.

Caution: The underseats are getting the signal all the way down to around 20Hz. If you play music with low bass content, you may be overdriving them, and they may blow. You may want to consider F-Mods on the inputs for the rears, to cut out frequencies below 40 Hz or so. The OEM drivers cannot take much power on the low end, but they are excellent above 40Hz (and most music will sound great high-passed at 40Hz). If you want authority in the bass department, you need a trunk sub.

[kaigoss69]

...and set the crossovers both at 250Hz (easy to set), that gives your midrange speakers a little more protection and I think it is close to the crossover point used by the L7 system.

[lendlease]

Originally Posted by kaigoss69

...and set the crossovers both at 250Hz (easy to set), that gives your midrange speakers a little more protection and I think it is close to the crossover point used by the L7 system.

Alrighty so some questions:

1. So how dangerous is it really to just run the underseats how they are right
now?

2. Say I have it like lowpassed ~200, would the low notes it actually tries
to play blow it?

3. 250hz highpassed for the mids/tweeters and 250hz lowpass for the
underseats?

4. I'm not doubting you, but do you have any sources for this being close to
the Logic 7 crossover? Most threads I see say crossover it around 120-150.

5. I know I've basically already asked this, but I'm pretty satisfied with the
sound/feel/bump of the underseats right now, so do you have any examples
of Logic 7 underseats being blown because of low frequencies?

Anyways, I've finally gotten installed and put back together. Things sound
really good how they are currently and I'm mostly just wondering if there
is a posibility that tinkering with the gain and crossovers would give me
any better performance. I think the best part right now is how aggressive
the underseats can get and shake the seats. I'm just a little worried right
now because I hope I'm not causing any damage because of the whole low
frequency issue.