Just curious, where do you guys like to set your crossover for your sub(s)?

My current setup -

Headunit - Alpine 9813
Fronts - CDT CL61
Lucid rears
Bass shakers in seat pockets (25W version)
Toolwell sub - Alphasonik 10, built by darkknight
Soundstream A4 for fronts (just 25W per side, sounded crappy bridged) - replacing soon with PG X100.2
PG X600.1 for sub (600W RMS)

To be entirely honest, I don't have that much experience with installs, though thanks to all the helpful information on this board I was able to install all the above successfully by myself.

But, where to set the low pass for the sub?

And, I should note, the bass sounds better with the windows and/or top down, my trouble is with the top up and windows up (seems kind of counter-intuitive, but that's the reality and I know others have mentioned noticing this as well). That being said, I do drive with the top up a lot of the time (rains fairly often here, and sometimes just don't want to "advertise" the system to everyone else...)


So these settings are with top and windows up, and the engine on / car rolling.

I started off with 125Hz, with the fronts high passed at 100Hz. This seemed okay but not that great. It seemed that the bass from the sub wasn't coming into the cabin well enough to make things sound balanced. Then I fooled with the time correction some more, set the fronts (virtually) farther out in front thinking the phase was off. This helped some, but it still seemed like not enough bass was getting through from the sub into the cabin. Shakes the trunk like mad at high volume but doesn't sound clear.

Or let me try to put this another way. With the sub turned off, I get pretty decent bass by most standards from the components plus bass shakers (full range signal to both, with engine on, car moving). The door panels are pretty thouroughly dynamatted.

When I cross the components over at 80Hz, with even just a -6dB slope and then turn the sub on, it seems like I am missing a lot of bass. Turning the sub input up eventually results in so much shaking that stuff (in the trunk, front dash, interior panels, everything really) begins to rattle, crapifying the sound before I can make the bass in the cabin sound as loud as the components with full range signal. If I keep the fronts full range and then add the sub, I don't really notice the sub at all until it just starts really vibrating everything. It does add some bass overall, but it's not that great of an improvement compared to just the fronts and the bass shakers at full signal with no sub. Not the massive bass injection I was thinking I would get...

Not knocking darkknight's sub box at all, seems well-built, but I was kinda expecting more sound in the cabin with 600W going to sub ...

I then turned the low pass for the sub up to 250Hz. Again, helped some (sounded louder in the cabin) but bass seems muddier than I would like at high volume, and I worry that this is going to possibly hurt the sub over time playing such a large range (40Hz high pass, 250Hz low pass)(is this a legitimate concern?). Currently set back to 125Hz ...

One other thing, the input level to the sub is set at 13/15 from the headunit and about 80% max on the sub amp. Does anyone think these settings are likely high enough to cause distortion at high volume? I've played with several settings and I don't think there is any clipping at this one. Plus the sub is rated for 800W RMS and the amp only 600W RMS ...

Seems like it might be helpful to do some things in the trunk - plug the air vent behind the bumper, dynamat the trunk, possibly remove the center part of the soft top tray. All fine and dandy, but the last two steps require a bit of work ...

Not trying to be lazy, but wondering if anyone has a similar setup (especially the sub - toolwell box and around 600W RMS for it) and what their optimization experience has been before I invest a lot of time (and some more $) in this ... Also, am I just expecting too much from a moving convertible?

Thanks for reading
JT

 

turn all EQ and other sound processing off
turn sub off... im not big on that bass shaker deal, esp if you have a real subwoofer
high pass for components should be from around 70-100hz... if you hear some distortion at desired maximum loudness then keep upping the component HPx a bit

sub shouldnt be fed signals above 150hz. the slope on the amp is pretty high, so not much overlap with components are needed. start near the high pass. play music at moderate volume level, then adjust sub gain to where it blends well with system.

that sets a base for the settings. now you can begin to FINE tune EQ. reserve sub level control to adjust sub output for every song

 

For my subs I only use a lowpass of 80hz. It has worked well for me in the past. It all depends on what type of music you listen to and what sounds right for you.

 

Thanks for the replies guys.

I put the sub at 80Hz today and set the eq to flat. It still seems like I'm losing too much bass from the components when I turn on the headunit crossover. Even if it's just set at 63Hz -6dB slope. Maybe my ears are just not trained to enjoy "accurate" music? I will try it your way a couple more times Smurf2k, just to be sure. Tomorrow I will Also try disconnecting the shakers to see if it helps me hear the sub more clearly.

I have decided I will also do the other mods I mentioned earlier (plug the trunk vent, dynamat, remove center of soft top tray - in that order) when I get time, probably over the next two weeks. Hopefully this will make things sound better when I try to tune the system using the methods suggested here and in the FAQ.

Guess I didn't say so specifically, but this is my first soft top car and my first subwoofer install, so I may have been expecting more than what was realistic for bass production in this car.

It seems the road noise is the killer. Everything sounds so much better when the car is stopped with the engine off. I'm starting to curb my expectations somewhat, but I'm still optimistic that I can get some very nice sound out of this system if I keep tinkering.

Right now though, at least to my ears, I am getting better sound with full range to the front components + shakers. May just be my particular musical taste or whatever. I don't necessarily want to wake the neighborhood, but I like to feel strong bass when I turn it up (without having the tweeters make my ears bleed). Maybe "my sound" would make an audiophile cringe, but hey, it's what I like...

If the above mods don't get me where I want to go, I can always add another sub I guess. Then pull up the front carpet and dynamat under there. Then get a hard top. Oh well, at least it's a fun project...

 

I think your problem might be the imbalance in your system using a 25W/Channel amp for your mains and a 600watt one for your sub.

Basically you're compensating for the lack of bass output your getting up front, by extending the frequency range of your sub up into the midbass area which it's really not designed for. I'd start by getting that pg x100.2 amp installed, set the crossover at 80hz...high and low pass, using a 12-18db slope as a good starting point. The only time I've used a 6db slope, is when the high pass has to be set really high (200hz or higher), for a small 3 or 4" speaker so I can get some degree of midbass out of them without distortion. And like Smurfs2k said, turn the EQ, and all other sound enhancements off to start. Then tweek from there.

 

Just an update, in case it's helpful to anyone else.

I took out the rear tray on sunday. It seemed to help the bass get into the cabin a lot more. There was some increased road noise, but not enough to bother me personally.

However I was still having significant rattling issues.

It sounded like the rattling was coming from the carpeted trunk panels, or from something behind them.

Yesterday, I went ahead and dynamatted the trunk. I also plugged the bumper vent.

With the dynamat, the road noise was reduced back to the level that I heard before taking the rear tray out. It also helped reduce the rattles tremendously.

I was still getting one annoyingly loud rattle from the center console - the doors were rattling against the body of the console. I put a few strips of two way foam tape on the lid edges (until I can find a better material for this - of course I only peeled the backing off one side...) and it quieted them nicely.

Now, at high volume, the sub output is nice. At the highest volumes there is some slight rattling, but it sounds distant and muffled. Not enough to bother me personally.

Also, this result was achieved without dynamatting the trunk lid. I wanted to try not putting dynamat there since it would be highly visible and I don't trust my cutting skills enough to think that it would look very good. Turns out I am satisfied with the sound without having to do that. I'm sure some would say that it's necessary, but doesn't seem to be in my case. YMMV.

One other thing. I am still getting less midbass from the front components than I would like when crossing them over. My solution was to turn the signal to the fronts down using the headunit. Setting this to -2 seems to allow me to find the happy medium of getting max midbass out of the components at near-max volume without clipping and without making the highs too loud. I think a better solution would be to install some in-line attenuators to the tweeters (between the tweeters and the crossovers) and I will probably have to do that after installing a more powerful amp for the front speakers (upgrading from 25Wx2 to 100Wx2).

Anyhow, the tweaks continue, but I will say I definitely did find it worthwhile to dynamat the trunk (more for rattling and road noise than making the sub noticeably louder) and to remove the center part of the rear tray. I think I will copy off of some of you guys who have modded the tray by cutting a big hole in the middle and covering it with some thin cloth.

My next question has to do with whether it's okay to turn the subsonic filter off if you have a sealed box. but I made a separate post for that one...

Hope this helps someone and thanks again to those who have chimed in with advice.

 

Just a quick update ...

My PG x100.2 amp came in, installed it to drive the front components today.

It definitely made an improvement, but not exactly what I expected ... turned out better than expected actually.

Going from a 25Wx2 amp to a 100Wx2 amp .... the sound doesn't seem really all that much louder with the extra power, but the midbass comes through noticeably stronger and the sub seems to blend much better with the fronts high passed at around 80Hz.

I was halfway expecting the components to overpower the sub with the new amp, since it seemed like the highs were too harsh already at high volume, but the exra power seems to have balanced things out better .... cool!

I also seem to be hearing some musical details that weren't coming through as well before. But what's especially pleasing is that the highs don't sound as harsh anymore at high volume. This difference is most noticeable with certain bands like Tool and The Hives who seem to emphasize the highs more in their studio mix. I figure it's probably just a trick of the mind caused by more balanced sound ... I am probably still damaging my hearing, but it's not as painful now

Other factors that might be making a difference besides the extra power might be that I am:

1. Using the amplifier's crossover instead of the headunit's (old amp did not have a highpass) - not sure how this would make a difference though, 80Hz crossover at the subunit should still be the same as 80Hz crossover at the amplifier in theory...

2. Using amplifiers from different companies - Soundstream (old) vs Phoenix Gold (new) - before this purchase, I had never heard that PG was noticeably better than Soundstream in terms of sound quality though, so it's probably just the power difference in this case...



Anyhow, I'm sure that people with more experience in car audio would have expected this (it's just like you said, DCon67), but I wasn't sure considering how the setup was doing with the previous amp.


Hope these ramblings can help someone else who is a noob like myself and is wondering about these things and still figuring out how everthing works together...

 

thanks for the post, interesting read and well typed.

 

probably not much in circuitry but power. its not louder unless you turn it louder. at same volume level, the highs sound better because the amp isnt being pushed and is not clipping/distorting the signals.

glad youre satisfied. i probably should get myself a sub for christmas