Simple guide to a miata trunk subwoofer
#12
What about the three layers of insulation that covers the parcel shelf? The carpet, padding/batting layer and rubberized layer of the uphostery along with the panel absolutely mute the amount of sound coming from the trunk. The apparent volume was much louder after I cut out the parcel shelf AND upholstery, then covered the hole with a speaker grill.
In addition, I removed the fuel line cover in the trunk, opening the pathway down the left side of the trunk just as it is on the right side. No cut-out of the parcel shelf on the left side yet, though I was thinking I might add one just to make it symmetrical. The woofer is a lot closer to the passenger side opening so I doubt I'd get much benefit from opening up the other side.
The parcel shelf was already partially cut to accept the roll bar - just cutting out a bit more material along with the upholstery was not difficult and it made a big difference.
#13
Jumbo, how many watts does that tube sub consume? I have an Image Dynamics IDQ12V3 in a .8 cu ft sealed box (Soon to be a ported box, 12 more db at 42hz OH YEAH) stuffed with polyfill hooked up to a RF 700watt rms amp. Also have 120watt rms powering 6.5" Polk door speakers. I am weary of cutting or removing the parcel shelf because my Walbro 190HP fuel pump whines like my girlfriend. For me, removing the shelf would outweigh the advantages of barely increased low frequency SPL.
#14
Jumbo, how many watts does that tube sub consume? I have an Image Dynamics IDQ12V3 in a .8 cu ft sealed box (Soon to be a ported box, 12 more db at 42hz OH YEAH) stuffed with polyfill hooked up to a RF 700watt rms amp. Also have 120watt rms powering 6.5" Polk door speakers. I am weary of cutting or removing the parcel shelf because my Walbro 190HP fuel pump whines like my girlfriend. For me, removing the shelf would outweigh the advantages of barely increased low frequency SPL.
The rear channel speakers are hooked into the 100W/Ch amp and the front speakers are hooked into the aftermarket head unit/amp. The gain is down on the amplifed rear channel as well - in order to match the front channel volumes. Playing with the crossovers and gains took a couple weeks but once dialed in, I rarely have to change settings.
The small space in the Miata works well with this gear, but I can tell it is on the edge of capability. Trying for more volume usually results in clipping or low frequency distortion. I'd have to upgrade the front & rear speakers to take it to the next level but probably won't since it ain't broke as it stands.
#15
the "bose" method is ok to a point. cheap components usually have much higher levels of nonlinear distortion when used near the boundaries of their comfort zone. without the proper equipment, it's hard to know where that is. you can compensate by playing things at lower volume, but you can't eliminate it.
#17
I have a 2000 Miata, is it worth replacing the door speakers with a component setup? Will I need an amp to power it?
I am sooooo ignorant about car audio, just want something louder and clearer so I can hear it with the top down.
Thanks!
I am sooooo ignorant about car audio, just want something louder and clearer so I can hear it with the top down.
Thanks!
#18
But no, a decent head unit will be more than powerful enough to drive the door speakers.
#19
It really depends on the speakers. If they're efficient (> 93 db/2.83V@1m sensitivity), it's like getting a free volume boost. if they're inefficient (<88ish) then they will do best with some amp power behind them.
Each 3 db you go up in sensitivity is equivalent to twice as loud / double the power. so if you compare a 90 to a 93 db speaker, the 90 will require twice the power to get to the same volume level. (assuming both are the same impedance)
Now... You dont need component if you replace them, but you should get a multi-driver setup. Coaxial is fine.
Each 3 db you go up in sensitivity is equivalent to twice as loud / double the power. so if you compare a 90 to a 93 db speaker, the 90 will require twice the power to get to the same volume level. (assuming both are the same impedance)
Now... You dont need component if you replace them, but you should get a multi-driver setup. Coaxial is fine.
#20
I made this up a while ago. It basically calls out a recipe for a good-sounding small trunk sub for a Miata. Ignore the naysayers. This is a proven and awesome setup.
http://fixjunk.com/index.php?title=Miata_Trunk_Sub
The theory behind this design is that it complements the small size of the miata and the peaky low end cabin gain from the trunk and interior. If you design your sub to have a flat response down to 20Hz, you end up with a giant gain in the low end and you'll just waste amplifier power and rattle your trunk apart.
More techy details of the testing done by Jason Cuadra can be found here:
http://www.diysubwoofers.org/projects/other/cartf/
http://fixjunk.com/index.php?title=Miata_Trunk_Sub
The theory behind this design is that it complements the small size of the miata and the peaky low end cabin gain from the trunk and interior. If you design your sub to have a flat response down to 20Hz, you end up with a giant gain in the low end and you'll just waste amplifier power and rattle your trunk apart.
More techy details of the testing done by Jason Cuadra can be found here:
http://www.diysubwoofers.org/projects/other/cartf/