After more SQ and deeper bass, given the exact same enclosure....?

[therapture]

First of all, hello peeps. Been lurking here a long while.

Basics:

1) 1.45 ft³ sealed enclosure, .75" MDF.

2) 350-400 watts of clean sub power available at 2ohm, ~175-200w at 4ohm

3) current sub MTX TR5512-44 (weak link?), low pass at ~65hz-70hz 24db, 15hz-25hz subsonic.

4) HAT I61-2v2 mids on mdf baffles, 135w x 2, highpassed at 85hz 12db, doors matted and sealed (I am really loving these babies).

I basically want to try a new sub to go along with my new HAT Imagine 6.5". I want more SQ and deeper response, so should I go for a lower Fs and higher sensitivity subwoofer as compared top my current MTX? I am not into slamming the poor sub to death anymore, I want clear, clean bass, but with the ability to crank it up occasionally. I am also after better transient response, assuming I need a stronger motor as per the T/S parameters? I listen to alot of high quality electronica such as Electric Universe, Astrix, Bluetech, Delerium, shpongle, vocal psytrance, etc., with forays into southern rap and an occasional whatever else, Pink Floyd, SRV, Tool, ad infinitum.

I cannot change enclosure size due to it being recessed and made into the spare tire well of my 2009 Pontiac G8 GT, except for stuffing it a bit with wood to cut airspace. Sealed is an absolute as well since I am after SQ and ease of install. I am just really getting into tuning for SQ and loving it, getting the phase correct on all speakers, crossover points, etc., now I want a better subwoofer. IS there a noticeable difference by changing to a "better" sub, considering I have it very well matched to my mids right now? IS there a large enough gain in SQ to justify spending 200-300 bucks on a new sub?

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[momax_powers 10+ year member]

you will get the most gain, with respect to sq and deep bass, from getting the right enclosure and tuning. You can spend 2000 on a woofer but it will sound like crap in the wrong box and tuned incorrectly. Your tuning doesnt seem to be the issue so it may be the enclosure size/positioning.....1.45 may be a little big aswell

edit: you can also achieve sq with a ported enclosure if built correctly...going ported may be the way to go when chasing that deep bass

 

[Electrodynamic 10+ year member]

First of all, hello peeps. Been lurking here a long while.

Basics:

1) 1.45 ft³ sealed enclosure, .75" MDF.

2) 350-400 watts of clean sub power available at 2ohm, ~175-200w at 4ohm

3) current sub MTX TR5512-44 (weak link?), low pass at ~65hz-70hz 24db, 15hz-25hz subsonic.

4) HAT I61-2v2 mids on mdf baffles, 135w x 2, highpassed at 85hz 12db, doors matted and sealed (I am really loving these babies).

I basically want to try a new sub to go along with my new HAT Imagine 6.5". I want more SQ and deeper response, so should I go for a lower Fs and higher sensitivity subwoofer as compared top my current MTX? I am not into slamming the poor sub to death anymore, I want clear, clean bass, but with the ability to crank it up occasionally. I am also after better transient response, assuming I need a stronger motor as per the T/S parameters? I listen to alot of high quality electronica such as Electric Universe, Astrix, Bluetech, Delerium, shpongle, vocal psytrance, etc., with forays into southern rap and an occasional whatever else, Pink Floyd, SRV, Tool, ad infinitum.

I cannot change enclosure size due to it being recessed and made into the spare tire well of my 2009 Pontiac G8 GT, except for stuffing it a bit with wood to cut airspace. Sealed is an absolute as well since I am after SQ and ease of install. I am just really getting into tuning for SQ and loving it, getting the phase correct on all speakers, crossover points, etc., now I want a better subwoofer. IS there a noticeable difference by changing to a "better" sub, considering I have it very well matched to my mids right now? IS there a large enough gain in SQ to justify spending 200-300 bucks on a new sub?

If you go with a driver with a higher sensitivity and lower Fs you will get a result of less bandwith and overall lower output. You cannot escape Hoffman's Iron Law. You can have piece of the pie, not all three at 100%. It sounds like you could benefit from a less sensitive (more output in a smaller enclosure) woofer if your goal is more output overall. Also, raise your low-pass to 80 Hz.

 

[therapture]

Don't get me wrong, I am not having bad SQ, I was just trying to go for MORE of it, thinking a new sub would help. Maybe it wouldn't? I Like I said, I do not drive it super hard, and excursion seems to be a long ways from max.

OK, so since my enclosure is almost 1.5, and MTX says to use a 1.0ft³...should I stuff the box to get there? Seems counter intuitive, seems that would raise the resonant frequency and make it boomy-er. The Qtc of my enclosure right now is high...like in the .9 range. Going smaller would raise it more. According to WinISD I would need a 2.5 -ish volume to get Qtc to .707

I also considered raising the crossover and trying a tiny bit of low end boost (2-3 db at 45hz) to make the curve "fatter" down low?

 

[therapture]

After further testing and some critical listening, I have found the plastic vibrating cans GM calls door trim panels, are a major source of extra noise that blur some of the detail, especially in the 55-80 hertz range. The door pockets are like little vibrating speakers, I can press on them fairly hard and stop most of it, but it appears I am going to have to find a way to deaden them as well. The sheet metal of the door is not an issue.

Looking for ideas for something to put on the inside panels to stop vibration and dampen the plastic. Mat? Liquid? A specialty material perhaps...

 

[neo_styles 10+ year member]

After further testing and some critical listening, I have found the plastic vibrating cans GM calls door trim panels, are a major source of extra noise that blur some of the detail, especially in the 55-80 hertz range. The door pockets are like little vibrating speakers, I can press on them fairly hard and stop most of it, but it appears I am going to have to find a way to deaden them as well. The sheet metal of the door is not an issue.
Looking for ideas for something to put on the inside panels to stop vibration and dampen the plastic. Mat? Liquid? A specialty material perhaps...

Sounds like you need to mass-load. Get some CLD on the flat portions of those trim pieces.

 

[therapture]

I am going to take them apart saturday and try a combo of some GTMat, thick dense foam (packing foam) to go between the door trim and door, and some 3M single sided adhesive foam tape to go around the perimeter of the door trim. Plus some silicone to fill in cracks in the different parts of the door panel and stop vibrating edges there. And I need to replace a couple of missing clips, that will increase the clamping pressure of the trim once installed.

 

[shadow 10+ year member]

Ya running a 6.5 driver down to 50hz ,... lol I bet you do have some buzzing going on with your doors.

CLD Foam to decouple your door cards will help...

And yeah u are going to need to find the right air space for that transducer...

 

[therapture]

Ya running a 6.5 driver down to 50hz ,... lol I bet you do have some buzzing going on with your doors.CLD Foam to decouple your door cards will help...

And yeah u are going to need to find the right air space for that transducer...

It's crossed over close to spec for that power level and slope, even a bit higher. The buzzing gets noticeable at 60hz and by 70hz, it's quite objectional. My car seems to have a lot of cabin gain in that range as well. I have been using the 1997 IASCA test cd and tone sweeps to find the problematic areas. I can only reduce box size so, it seems that even though the MTX is recommended for a single ft³ of sealed space, that indeed, it's a poor choice since I can imagine that high of an alignment will be a boomy, ringing, muddy mess? Perhaps I should be looking into finding a driver that will result in a Qtc of .707, +/-.05 in my current sealed enclosure?

I tried running the crossover to 80hz on the sub but it gets a peak in the response that does not blend well with my mids and it becomes localized behind me, I can't stand that much. It sounds very nice at a 70hz crossover.