Got a little different project going some car audio.
I've obtained a new ute (little mini truck for my American friends) its a 2008 single cab flat tray Mazda BT50.
Just started working on it today making the sub box and planning out the door speakers... man I hate using fiberglass. Being such a small cab there is no real room for the sub in a conventional shaped box so Im making the box as a center console between the seats and it'll go up the rear cab wall to the window, I can only manage approx 30ltrs(1 Cf) of volume which is ok for most 10~12" car subs but Im lacking in width(230mm between the seats) so Im going to run 2x 8".
Parts list so far
2X Dayton UM8-22's
Door's will contain a Dayton RS225-4 for midbass duties, some Philips GTM 4" for midrange I've had them for years never used, and Im thinking of using some tweeters I've had for years also Jaycar response 19mm or the ones supplied with the GTM's.
Also have a Dayton 408 DSP to allow me plenty of adjustments and I'll be reusing an Alpine MRX-V70 5ch amp from my old ute, the UM8's will be wired for 2ohm on the sub channel and the RS225's on two channels and the GTM/tweeters on the remaining two channels, if there's not enough watts for the RS225's I will bridge the four channels into two and buy a small 2ch amp for the GTM/tweeters it'll all depend on how its measures when I get it up and running.
The Midrange and tweeters will need a passive xover made or I could use the ones supplied with the Philips GTM's... I'll have to do some testing/measuring may even end up buying some small coaxials or another set of 4'' splits(Focals would be nice).
Anyways that's where I'm at, I'll post up some progress pic's in a few days.
I've obtained a new ute (little mini truck for my American friends) its a 2008 single cab flat tray Mazda BT50.
Just started working on it today making the sub box and planning out the door speakers... man I hate using fiberglass. Being such a small cab there is no real room for the sub in a conventional shaped box so Im making the box as a center console between the seats and it'll go up the rear cab wall to the window, I can only manage approx 30ltrs(1 Cf) of volume which is ok for most 10~12" car subs but Im lacking in width(230mm between the seats) so Im going to run 2x 8".
Parts list so far
2X Dayton UM8-22's
Door's will contain a Dayton RS225-4 for midbass duties, some Philips GTM 4" for midrange I've had them for years never used, and Im thinking of using some tweeters I've had for years also Jaycar response 19mm or the ones supplied with the GTM's.
Also have a Dayton 408 DSP to allow me plenty of adjustments and I'll be reusing an Alpine MRX-V70 5ch amp from my old ute, the UM8's will be wired for 2ohm on the sub channel and the RS225's on two channels and the GTM/tweeters on the remaining two channels, if there's not enough watts for the RS225's I will bridge the four channels into two and buy a small 2ch amp for the GTM/tweeters it'll all depend on how its measures when I get it up and running.
The Midrange and tweeters will need a passive xover made or I could use the ones supplied with the Philips GTM's... I'll have to do some testing/measuring may even end up buying some small coaxials or another set of 4'' splits(Focals would be nice).
Anyways that's where I'm at, I'll post up some progress pic's in a few days.
The start of the sub box, this just the outer shell after the cardboard mock up will be adding mdf and more fiberglass
The rear face where the speaker baffle will be, this faces the rear wall of the cabin
And the current speakers, the mid and tweeter may change but the UM8-22 and the RS225-4 are staying
The rear face where the speaker baffle will be, this faces the rear wall of the cabin
And the current speakers, the mid and tweeter may change but the UM8-22 and the RS225-4 are staying
Last edited:
A little progress, found a heap of form plywood in one of my sheds.
Mostly 17mm(.67")and 2 layers of 9mm(.35")kerf cut and laminated together on the curved part all bonded with fiberglass resin, once I've lined it fully with ply Im going to glassfiber filler any gaps then another layer of 600gm chopped strand matting over the whole lot encapsulating the ply fully. I will add some cross bracing between the sides also.
The pictures here show the box cleaned up enough to test fit it, I needed to do this to see how far the baffle will need insetting to allow clearance for that 16mm of xmax on the UM8's.
I drove it a couple times with the box in place there's no hinderance at all... happy about that
There's a bracket in the middle of the rear wall that will need to be removed, other than that I worked out the baffle will need insetting by 20mm(3/4")and the fiberglass shell cut back to that point, this will allow a good 32mm(1 1/4")from the speaker surround at full Xmax. At 16"or so high the box will be moulded to the rear wall with a bracket that'll bolt to the two trim plugs above the box, they'll need some rivnuts put in and the trim along the rear windscreen will be cut away and resecured to the box.
The square hole at the front near the gear stick will be made into a tray/dock for my phone to plug into the head unit so I have full control of the phone for things like Spotify and google maps etc. via the Android auto app. I wanted fully wireless integration H/U but they are near impossible to get here in Australia... in any brand.
Did have a big set back 😢 spent almost a whole day making a baffle getting it to fit in very nicely lots of angles... upon cutting the second speaker recess for flush mounting the spiral up cut bit in my router decided to walk its way out from the collet(uses an adapter 8mm to 1/2") cutting completely through the baffle also putting a massive gouge in my outfeed table for my tablesaw😡
On a good note I found some better tweeters I had laying about some Dayton ND25FW-4(4 ohm wave guide/silk 1"dome/neo/ferro fluid), these will be an easier fit in the doors due to the tiny neo magnet, the Jaycar have a large bucking magnet... not needed(thats how long I've had these sitting for, tube TV!)
Mostly 17mm(.67")and 2 layers of 9mm(.35")kerf cut and laminated together on the curved part all bonded with fiberglass resin, once I've lined it fully with ply Im going to glassfiber filler any gaps then another layer of 600gm chopped strand matting over the whole lot encapsulating the ply fully. I will add some cross bracing between the sides also.
The pictures here show the box cleaned up enough to test fit it, I needed to do this to see how far the baffle will need insetting to allow clearance for that 16mm of xmax on the UM8's.
I drove it a couple times with the box in place there's no hinderance at all... happy about that
The square hole at the front near the gear stick will be made into a tray/dock for my phone to plug into the head unit so I have full control of the phone for things like Spotify and google maps etc. via the Android auto app. I wanted fully wireless integration H/U but they are near impossible to get here in Australia... in any brand.
Did have a big set back 😢 spent almost a whole day making a baffle getting it to fit in very nicely lots of angles... upon cutting the second speaker recess for flush mounting the spiral up cut bit in my router decided to walk its way out from the collet(uses an adapter 8mm to 1/2") cutting completely through the baffle also putting a massive gouge in my outfeed table for my tablesaw😡
On a good note I found some better tweeters I had laying about some Dayton ND25FW-4(4 ohm wave guide/silk 1"dome/neo/ferro fluid), these will be an easier fit in the doors due to the tiny neo magnet, the Jaycar have a large bucking magnet... not needed(thats how long I've had these sitting for, tube TV!)
Got another baffle made... the UM8 only just fits in the top cutout will need a small scallop cut into one side(the box isn't symmetrical)the lower UM8 fits with plenty of clearance.
Now I know the subs fit I can finish the baffle by doubling its thickness and lining out the rest of the box with plywood, then I'll fill any gaps and make a radius in all corners with fiberglass impregnated filler finally finishing the whole lot with another layer of 600gsm matting overtop on the inside.
After all that is done some internal bracing in a T shape will be affixed in place with screws and probably a generous fillet FGI filler around each leg wherever the touch to glue them in super solid.
Now I know the subs fit I can finish the baffle by doubling its thickness and lining out the rest of the box with plywood, then I'll fill any gaps and make a radius in all corners with fiberglass impregnated filler finally finishing the whole lot with another layer of 600gsm matting overtop on the inside.
After all that is done some internal bracing in a T shape will be affixed in place with screws and probably a generous fillet FGI filler around each leg wherever the touch to glue them in super solid.
Made my mind up to go full active, I tried mucking about with a passive crossover between the Philips GTM1020 and Dayton tweeter made up a big baffle from mdf to simulate being mounted in a door, took separate FRD's of each put them in Xsim.
No matter what I did the GTMs have a massive suck out between 800~1200Hz like 20db down, I tried removing the grill and then the grill surround and still it measured with a huge suckout 😡 even measured in free air still the same.
I though maybe its something to do with the baffle so I mounted up a old 5"polk midbass and the suckout disappeared.
I've brought a pair of Dayton RS100P-4's to replace the GTM's and another amp a DS18 ZXi-4(4x125wrms), this will allow me to bridge my Alpine amp 4 channels into 2 so it can run the Rs225's midbasses and the two UM8 subs on the mono sub channel(@2ohm) essentially making it a 3ch amp.
The DS18 ZXi-4 was chosen because it has a more versatile crossover section as its designed to run full active(xover is up to 8khz) unlike the Alpine(xover maxed @200Hz), This will give me many options and give my midranges and tweeters extra protection just incase I mess up the tuning with the Dayton 408 DSP... their going to need it with 125wrms of power each 😵
Bog work in progress(Bondo), been trying out the milkshake method by mixing filler with about 10% polyester resin and some acetone(cant get MEKP here) and brushing it on... so much easier over rough fiberglass.
As you can see I wanted some raised radiused edges along the front edges, this will allow me to lap over some fake leather over the edges and I'll make up a insert to cover the middle out of metal with some flush mounted magnets to hold it in place thats the current plan... that may change though.
Made up a little tray to hold my phone, was going to make it into a dock with a male usb C plug but ended up being to much hassle so now will just use a cord
I have to say this is craziest sub box I've ever made!
Its ended up approx 32ltrs I measured it before mounting the baffle I filled it with water(it is completely lined with FG)to the baffle line, minus off the sub's volume it'll be approx 30ltrs. That'll give each driver decent enough vol for good shallow roll off without needing a bazillion watts.
No matter what I did the GTMs have a massive suck out between 800~1200Hz like 20db down, I tried removing the grill and then the grill surround and still it measured with a huge suckout 😡 even measured in free air still the same.
I though maybe its something to do with the baffle so I mounted up a old 5"polk midbass and the suckout disappeared.
I've brought a pair of Dayton RS100P-4's to replace the GTM's and another amp a DS18 ZXi-4(4x125wrms), this will allow me to bridge my Alpine amp 4 channels into 2 so it can run the Rs225's midbasses and the two UM8 subs on the mono sub channel(@2ohm) essentially making it a 3ch amp.
The DS18 ZXi-4 was chosen because it has a more versatile crossover section as its designed to run full active(xover is up to 8khz) unlike the Alpine(xover maxed @200Hz), This will give me many options and give my midranges and tweeters extra protection just incase I mess up the tuning with the Dayton 408 DSP... their going to need it with 125wrms of power each 😵
Bog work in progress(Bondo), been trying out the milkshake method by mixing filler with about 10% polyester resin and some acetone(cant get MEKP here) and brushing it on... so much easier over rough fiberglass.
As you can see I wanted some raised radiused edges along the front edges, this will allow me to lap over some fake leather over the edges and I'll make up a insert to cover the middle out of metal with some flush mounted magnets to hold it in place thats the current plan... that may change though.
Made up a little tray to hold my phone, was going to make it into a dock with a male usb C plug but ended up being to much hassle so now will just use a cord
I have to say this is craziest sub box I've ever made!
Its ended up approx 32ltrs I measured it before mounting the baffle I filled it with water(it is completely lined with FG)to the baffle line, minus off the sub's volume it'll be approx 30ltrs. That'll give each driver decent enough vol for good shallow roll off without needing a bazillion watts.