This is the racetrack 8" driver that I introduced in the Bass Shelter thread. It is an unbranded driver sold as a replacement for a name brand boombox. It's 130mm slim across the narrow, and I can think of some fun applications if the driver is good. Build quality is visually superior to Dayton Reference passive radiators on hand. The driver is sold on Ali and is fairly expensive at $104 AUD for a no name. It's proportions and the promise of a decent 40hz low end as touted by the name brand makes it interesting enough to take a punt on. It will also suit the intended beach environment
Comes very well-packed
On the Datsv3, driver not yet broken in
Will stick to plan and take power from the sub section of the current Logitech z623 for breaking in and initial listening. The driver doesn't come with radius info for the cutout, so I will have to do some trial and error to get it right. It does come with a template so I can hack out a cutout for breaking in purpose
Will use the laser cutter CNC router thingy to get the cutout and recess just right for a proper cab in due time. The driver also appears to require a dress trim. The screw holes are very close to the edge of the rubber roll surround glue line. I hate the idea of screw heads crushing this. What do you guys do in this situation? The best I can think of is an alloy plate dress ring in CNC and with matching screw holes to clamp down over the driver's folded up edge. Mounting from behind the baffle will solve this too and have the same clamping effect. Actually, this may not be a bad thing and the material thickness can contain the excursion and just allow a simple grill over the driver
Welcome your thoughts on this unit
Comes very well-packed
On the Datsv3, driver not yet broken in
Will stick to plan and take power from the sub section of the current Logitech z623 for breaking in and initial listening. The driver doesn't come with radius info for the cutout, so I will have to do some trial and error to get it right. It does come with a template so I can hack out a cutout for breaking in purpose
Will use the laser cutter CNC router thingy to get the cutout and recess just right for a proper cab in due time. The driver also appears to require a dress trim. The screw holes are very close to the edge of the rubber roll surround glue line. I hate the idea of screw heads crushing this. What do you guys do in this situation? The best I can think of is an alloy plate dress ring in CNC and with matching screw holes to clamp down over the driver's folded up edge. Mounting from behind the baffle will solve this too and have the same clamping effect. Actually, this may not be a bad thing and the material thickness can contain the excursion and just allow a simple grill over the driver
Welcome your thoughts on this unit
Find a roll of electrical tape or a shape that will sit on or over the dust cap and measure the suspension stiffness using it as an added mass in the section above the measured ‘RE’ .
You need a digital kitchen scale or similar cheap (precise) way to determine the ‘a
dded mass’
You need a digital kitchen scale or similar cheap (precise) way to determine the ‘a
FWIW, if you add mass till Fs is lowered 1.56x you'll in theory get the most accurate measurement (as I understand it and used).
You can use nickels to add mass for testing Vas if you don't have a scale. Each one weighs 5 grams exactly.
Make sure to place them on the center of the cone dust cap for the most accurate results and clamp the driver in a vise. The better you couple the driver to a solid mass, the more accurate Vas and other TSPs will come out.
Make sure to place them on the center of the cone dust cap for the most accurate results and clamp the driver in a vise. The better you couple the driver to a solid mass, the more accurate Vas and other TSPs will come out.
Randy lives in Australia, where since 1966 a nickel (a 5 cent coin) weighs 2.83 grams, and a 10 cent coin weighs 5.65 grams.
I bought some play dough for this purpose. Have 300g on hand to cover up to the larger sized drivers. Hope this suffices
Clamping is turning out to be a bit problematic. I don't have a vise yet, and difficult to source one here. Broke the one from Bunnings. How bad is it using a backless box to mount the driver securely? Would the walls of the box affect Datsv3 results? If that is a no-go, how about just baffle only to hold the driver?
Dunno.
Originally did just that mounted to a seat less chair and used various size tin cans as required perched on the driver to add weight.
@Randy Bassinga Installing a driver to be measured in any baffle, with or without sidewalls will put a greater air load (more Mms, lower Fs, higher Qts). If the published driver specs are measured in an IEC baffle, then you should see similar results as per manufacturer specs.
Not clamping a driver when measured will definitely show different TSPs.
Modeling clay or blue tac works well for added mass Vas measurements.
Not clamping a driver when measured will definitely show different TSPs.
Modeling clay or blue tac works well for added mass Vas measurements.
What would be a good clamping method for such a driver? It doesnt have a vent, how about hot glue to the table top?
As long as any vents aren't blocked and there are no large reflective surfaces close to the back, you'll be ok ie. corner of table top.
The driver in your pics should be laid on its side. The reflective table top right behind it will screw with the midrange impedance curve.
You could use a large padded carpenters clamp to hold it by the magnet on its side to the table top corner with the front facing out.
The driver in your pics should be laid on its side. The reflective table top right behind it will screw with the midrange impedance curve.
You could use a large padded carpenters clamp to hold it by the magnet on its side to the table top corner with the front facing out.
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That driver would do well in a MLTL, sealed or TQWT. It haa a high-ish Qts and a very long VC for its size. Probably in the low 80dB / 2.83V sensitivity range.
I do have the service manual for the BB3, but the pics and text in that is protected
From the website
The service manual bears this out, but let me make it clear now, this is not a cloning attempt. I do intend to use it in a portable instrument amp as it seems to be a commercially proven driver and from what I have heard around the beach, JBL are serious about touting Pro abilities. It will form a sub for the e-trike, portable workbench, portable PA, two-way with FR desktop monitors and maybe even the car front doors. Lots of potential if this one tests ok
The BB3 uses a pair of 6.5" or so passive radiators, as seen in this YT teardown
@weltersys
Art, I think this might be a good fit in the Club Sandwich cab with its dual opposed SBA racer PRs on the sides. I can adjust the cab volume. The bass on the BB3 is certainly loud enough for that job
@Booger weldz
Boogs, I am thinking a pair of tapered TLs without bends. Tall narrow boxes with the narrow end down firing, conga like. Drivers mounted a 3rd down from the fat end and in a two-way with an FR driver like the 2.75" TB units with Madonna bra cups. The xover point in the BB3 is 300hz
Thanks for all the tips. Would love to hear your thoughts from the teardown vid. The first use will be as a sub for the e-trike and the mains will a pair of satellites mounted on the handlebars using waterproof FR replacement drivers from a Harman boombox, also sourced from Ali. I bought a pair of these Visaton from Mouser, but one arrived with a broken off magnet. They replaced it, but I lack confidence in it
https://au.mouser.com/ProductDetail/243-FR8WP-4OHM-BLK
From the website
The service manual bears this out, but let me make it clear now, this is not a cloning attempt. I do intend to use it in a portable instrument amp as it seems to be a commercially proven driver and from what I have heard around the beach, JBL are serious about touting Pro abilities. It will form a sub for the e-trike, portable workbench, portable PA, two-way with FR desktop monitors and maybe even the car front doors. Lots of potential if this one tests ok
The BB3 uses a pair of 6.5" or so passive radiators, as seen in this YT teardown
@weltersys
Art, I think this might be a good fit in the Club Sandwich cab with its dual opposed SBA racer PRs on the sides. I can adjust the cab volume. The bass on the BB3 is certainly loud enough for that job
@Booger weldz
Boogs, I am thinking a pair of tapered TLs without bends. Tall narrow boxes with the narrow end down firing, conga like. Drivers mounted a 3rd down from the fat end and in a two-way with an FR driver like the 2.75" TB units with Madonna bra cups. The xover point in the BB3 is 300hz
Thanks for all the tips. Would love to hear your thoughts from the teardown vid. The first use will be as a sub for the e-trike and the mains will a pair of satellites mounted on the handlebars using waterproof FR replacement drivers from a Harman boombox, also sourced from Ali. I bought a pair of these Visaton from Mouser, but one arrived with a broken off magnet. They replaced it, but I lack confidence in it
https://au.mouser.com/ProductDetail/243-FR8WP-4OHM-BLK
I drove a taxi for 7yrs. You know those days when someone tries to pay with pocket fulls of coins! Hold the shrapnel 😛
I sometimes hold the driver firmly against a (heavy) desk:
For a rough first estimation that should be enough. Just make sure the driver and your hand keep very still while measuring.
Looks like they are around 140mm outer diameter, the inner disc 104mm.
If only things like this were as audible as they are visual …. I wish we understood the connection between our vision and overloaded serotonin/dopamine circuits ….
Attachments
What drives us? Our culture recognises 4 things that drive us. The foremost is Kama
It's constantly foremost on our minds, first need when waking up and can't sleep without it again, and every moment in between somehow touches back to thoughts of it. This drive is stronger and needs to be well taken care of before one can truly entertain the idea of the other three drives. Revel in Kama to control it instead of trying to tamper it down. Simmering it down to control it doesn't take care of it and is prolly promoted by those that don't get their face sat on much
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