So I've replaced the OEM 6x9 subwoofer with a huge 12" subwoofer in an enclosure (+ added a 1ch amp) and the bass is super-deep tone, which is great and typically considered highly sought after sound, but it also leaves a hole in the acoustic spectrum above the subwoofer's frequency and below the factory Alpine/Jaguar midrange speakers.

Is there a way to adjust the crossover on the factory premium-amp or digitally from the head-unit?

If not, would adding a small 8" second subwoofer balance out the boominess of the 12" and make it blend in with the midrange/tweeter drivers?

 

I think your box may be your answer, ...are you running a ported or sealed box? To ask...so considered highly sought after by whom? Me, I want crisp tones because I like acoustic instruments (Blues & Swing), but I also like to Rock. So in my case a sealed unit gives me that sound.
If you want boomy bass, then a ported unit is probably your cup of chili and allows you to use a smaller amp.
Here's a reply on different sub setups with different music from Crutchfield:
Pop: “The ported had more punch but sounded muddy. The sealed sounded better to me on this one.” – Travis, Designer
• Rock/Alt: “The sealed sub delivered more emphatic bass. The ported was louder, but it got away from the music.” – Duke, Advisor
• Classical: Two Advisors heard no difference for the cello-heavy piece we chose to play.
• R&B/Rap: “The bass definitely sounded more natural with the ported box for the Rap.” – Dolly, Advisor
• Electro/Dance: “The ported sub sounded and felt better to me for this song. It accentuated the quality of the bass.” – Larry, Advisor


Here's an article that may help your design, whether it be the one you have or if you need to reshape it...http://speakerdesignworks.com/Sealed_v_Vented_2.html

 

Also adjust the factory deck for a different stage setting (Front, All, Rear, etc). Because they alter the sound quite a bit, and might me a big change in what you're hearing. I can't remember how many button presses it is, but it's fairly easy to find in the options.

 

Charlz, tried that already, the "front" setting definitely sounds better than the default "all" - not sure what it does, but it really alters the sound significantly.

Highhorse, it is a sealed box filled with loosely-packed polyfill and it is a small box with relatively little cu/ft of space (I need the trunk space). I definitely like the ultra-deep low-hz bass, don't want that to go away, just need to fill up the top until it gets to the midrange frequencies.

 

Are you using the old stock speakers still? I don't believe you'll get a proper balance sound as long as you use them, especially at higher levels. They were very good speakers when they came out, but, they are probably a little worn. Charles and I both replaced ours with Rockford Fosgates, I don't recall which ones they were. But they have 3 types now vs only 1 when I got mine with the tweets. The R165S, P165SI and R1675S (I think I got these), Find what fits your car - Crutchfield Fosgate. Not trying to make you buy new speakers, just giving you a reference.

 

This is like replacing a doorknob on an old house, it makes the door look old, so you change the door, which makes the house look old, and you end up remodeling the whole house, lol...

I'm not swapping the speakers, they work well and sound good (not amazing, but good enough)

 

That's the downfall with eliminating the factory 6x9 sub. While it doesn't reach as far down as your 12" does, it reaches lower than the door speakers. I'm not sure how the factory amp crossover is set up, or what kind of cross over / Low Pass filter is in your amp, but it really does limit what you can do with it. A few options:

Try sourcing your input from the door speaker wiring from the rear doors, and see if you can use the "full range" signal they're getting to give you more range (assuming it's a signal issue and not just because your 12" doesn't reach high enough).

You could replace your speakers with ones that have a bit more depth of range, though you've said you would rather not do that.

You could re-wire everything completely, pulling everything into a multi-line crossover, feeding out to a 4-channel amp and then back out to the speakers, which would give you full(er) control over the ranges sent to the factory speakers.

You could also see if you know anyone with different boxes, sizes, styles, and see if any would be willing to meet up to swap as a test to see if there's an alternative that you might be able to compromise with, if it came to that. If it's a slightly larger box that fixes your sound stage but isn't so big that you feel you're losing so much space, there might be an answer.

All that said, your amp has a cut-off at 90hz going up, even though your sub can reach up to 220. But, I don't know what the factory amp cutoff is, so of all those options, the easiest to test would be pulling a feed from the rear door speakers and seeing if changing to that signal would give you more. It seems rather ineffective, since in theory the factory amp would've had a high enough cut off to not allow for such a gap between the factory 6x9 sub and the full range, but the factory sub also probably didn't go down nearly as far as your 12" either and without as much power to push it, so the gap is likely more pronounced.

That's really the only easy way I can think of, that you'll be able to gauge and test the full system when you can hear everything, instead of trying to test just the sub sound by itself.

In the grand scheme though, there will be a point where you're going to be faced with settling for what you've got, versus changing more components. And, not to mean this in a bad way, but you're also not exactly using high end pieces to your puzzle at the moment, so you're bound to have some holes in the picture.

 

Your asking for control over certain ranges with an outdated system...that doesn't happen with a stock head unit, especially from '02 era, Alpine system or not, your limited. You may find a happy median to live with, but not the control you speak of. C'mon, fuget 'boutit...you know you want to remodel...:icon_speaker1 :

 

That seems like a bit of a contradiction, given your problem.

Unfortunately you're always going to be hindered by the factory crossover points built into the factory amp. But there are a couple of things that might help.
Firstly, make sure you're running your sub amp low pass filter either off, or as high as practicable. You might find that 'hole' is because you've cut out some frequencies yourself.
Second, if you don't want to upgrade the door speakers (more on this later...) then you might as well help get the most out of them. Add some sound deadening to your door skins, and make sure all the trim clips are there and that they are tight. If you wanted to go further, consider making adaptors so that the speakers mount to the door itself, not the door card. It's a lot more rigid, and will sound measurably better.

But really, I'd be looking to upgrade the speakers as well. Again, you'll always be limited by the factory amp, and it's crossover points. You might be able to keep the factory tweeters, which makes installation easier. You'll also want to look for speakers with quite a high efficiency, to give them the best chance of playing loud and low on the small amount of power they're being fed by the factory amp. Adding another amp for the door speakers would help as well, and you should be able to find something in the 50-75wrms per channel range that will take speaker level inputs.

 

Replace all the speakers is the best remedy.

 

Any chance that adding an additional 8" sub balance that out at all? That is the easiest option in terms of labor.

Very good suggestion, I'm sourcing now from the OEM sub wires, with the 1ch. amp crossover/filters turned off.

I'm very averse to doing more labor, if it is an option, I'd rather just buy stuff that goes in easily and fixes the problem. (choosing $ vs. time)

 

The door trim is relatively loose in both front doors, I've never been bothered by its aesthetics enough to determine why or how to fix, the driver's door has been reassembled for a prior lock-cable swap and everything looked fine inside, it just does not fit totally flush at the bottom. I assumed it was attributed to so few mounting points (only held on by a few small clips, one big clip and 2 screws.)

 

if it's the factory amp cut-off that is causing you to be missing range, it won't make a difference if you're still using the same source.

Unfortunately, aside from either changing the signal in to see if it's the factory crossover that's cutting you off, or changing out your box to see if the tuning is what's doing it, then the only thing you'd be left with would be bigger changes, and without the labor yourself, you'll be left spending $ for someone else to do that labor for you.

For what it's worth though, the door cards come off in about 5 minutes each, and the factory speakers are cake to get to and replace. Obviously there is SOME labor in doing that, but it's minuscule. However, you would be spending money on other speakers at the same time.

With how these systems are designed, there is no easy plug-n-play that will just fix all the issues. The only one that would, would've been to repair the factory sub. That leaves your real low end lacking. It's a one hand or the other after that. If you are going to impose limits on what you are willing to do or not do, then you're also going to have to resign yourself to living with the limits of what you end up with.

My suggestion is to find a full range signal first, use that and try tweaking your amp low pass and see if you can find a happy medium. if that doesn't help, then it's possible your box tuning has a dead spot above a certain point but you'd have to try another to see if it would change enough to make it worth it.

Oh, another idea if you can: try playing a tuning curve sound file and see if you can isolate where the range is that you're missing. They go through the range so you'd hear where there's a big drop in sound from the factory full range, and then see where you really start hearing the sub picking back up. Assuming you have a way to play something through your radio, be it a blue tooth adapter, or whatever. Even a tape adapter with really eh sound quality would at least give you a rough idea. Something like this clip:


It might at least give an idea, and let you see what your adjustments and changes are effecting.

 

Good point, doh!

My idea was that maybe the large 12" sub was reproducing signals at a lower/deeper frequency than the signal source?? But I guess the vibration frequency would be fixed regardless of the driver size/type so an 8" may have more response at the cost of reduced sonic-force (less air moving), but would not produce a higher frequency range.

Tempting, lol, is there really that much of a sound difference changing the door-mounted drivers?

Also, are the door drivers really getting a full-range signal?? Wouldn't the crossover of a sub-enabled system send the low-end to the sub-only, not to the midranges?

That is a brilliant suggestion! Thank you, I'm off to fiddle with the car now...

 

Rockford Fosgate P165 are great bang for the buck replacements for the cabin speakers.

 

Holy smokes, the sub starts vibrating at 28hz, is clearly audible at soul jarring 33hz (maybe due to my hearing limits, not the hardware), becomes downright deafening waves of bass at 50-80hz, and the crossover starts cutting off the sub at 105hz, and at 115hz it stops vibrating altogether.

The Alpine drivers barely reproduce any bass until 135hz, and don't reach full volume until 190hz, so 105-190hz is the hole!

Fyi, the upper limit I can hear (or maybe the limit the Alpine drivers can reproduce) is 16khz

 

If you're losing mid 100's then definitely look at door speakers. Sounds like the sub is working as it should, having extension down to 33hz is a good response for your setup. It would be possible to drive the sub up to 200hz but you'd need a much smaller driver, would lose low end extension and volume, and muck up your soundstage, assuming the factory amp is even feeding those frequencies through its sub outputs.

Due to the way the door speakers are mounted in the door cards instead of to the door itself (really jaguar?) even a little bit of gap/looseness in the door card mounting will affect sound a lot, as the energy at those low-midrange freqs will be wasted into vibrating the panels instead of pushing sound waves (another reason why sound deadening helps). I saw in another thread where someone had a shop build door panel speaker mounts to replace the oem speaker setup, and that apparently made a huge difference.

Both the door panel mount setup and replacing the silly fir tree clips/mounts are in my future for the front doors. New speakers may be worth considering too.

 

That would be me
It's a bit hard to explain, so I'll let the pictures do the talking. There were, by all accounts, very simple to make. The advantage of pods behind the door cards is that they don't have to look perfect, like they would if they were visible.

Glens XJR by Nath Wilson | Photobucket



All access holes were sealed, and sound deadening was applied over top as well, which can be seen in other pics

 

That is some nice work grandell, that looks like it took some time. I like the cricket...

 

Thanks. Wasn't done by me, was a friend who runs a custom audio business. The 'cricket' is a Weta, one of NZ's natives

The pods didn't take him very long either.
From what I remember, and can see in the photos, he pulled the factory grill off, temporarily hot glued mdf rings to the door card, put them back on the doors, fixed the rings to the door itself, detached them from the door card, and glassed them to a small panel he'd made to mount them to. Then just a quick trim, sand and paint.

Any good shop should be able to do the same in a few hours