rattle_snake's random shop projects v0.1

[rattle_snake]

Added some internal bracing to 15" sub box. Can go crazy with bracing for high pressure systems but went simple for this box.

After doing a 'knock' test the back was the worst/largest area/lowest freq so added a brace there too.


Basic box complete. Can't decide on style/color/grill/material yet so have to wait for something profound to pass through my feeble mind.

Double 10" box built up. No need for bracing with center divider.

Old chop saw cart under the knife. Cordless bandsaw for the win. Sometimes having the right tool makes you want to buy more tools.

Shrunk to a 6U size. added some provisions for mounting rack rails at 19".

Touched up paint, installed rails and made some end caps from MDF covered in boring black vinyl.

Installed the gear. Crossover has a bad channel but only need one here so perfect use of an old broken turd. The 1997 vintage amp still going and better than the Line6's internal 75w+75w. Rails are supposed to be 10-32 thread, shipped with 12-24 hardware, but are actually 5mm-something.

Power strip out back to wrap up the rig. This will be the base (on wheels) and the speakers and head will stack above.

 

[lilscorpion]

Them is the weirdest ******** boxes I ever seen.

Maybe I need to swing by and listen to what a real shop sound system sounds like. Bet your shop is no joke

 

[rattle_snake]

Them is the weirdest ******** boxes I ever seen.

Maybe I need to swing by and listen to what a real shop sound system sounds like. Bet your shop is no joke

Well if you are down in this part of the country stop on in!

At this point I think it is pretty impressive. It can deliver an authoritative pressure wave through your body.

I believe my wife finally ordered the Rockford Fosgate P3 10's to replace the $50 specials. The P3s have a better motor structure with more excursion. At this time the cheap 10's reach their mechanical limit before the amp clips. Not sure it will be any louder but will be more controlled and robust/safe at high power.

I should be receiving my shipment of speakers today. 15" for the guitar rig and an 18" for the shop, well because. Adding to the spectacle and more power is always good.

 

[plain2car]

Justin!... you're crazy!!! .. I would love to hear that in my little 3car garage & an HOA!!

 

[lilscorpion]

Justin- how would I go about selecting an amp for driving some subs in the shop? I could easily go there.

And I like the fosgate P3’s. Have them in the jeeps.

 

[Bigblue&Goldie]

Justin!... you're crazy!!! .. I would love to hear that in my little 3car garage & an HOA!!

Haha! Me too....

Me and my neighbor have competing portable Bluetooth speakers going and Justin has a stadium setup in his garage!

 

[rattle_snake]

Justin!... you're crazy!!! .. I would love to hear that in my little 3car garage & an HOA!!

Yes my shrink would agree. It would fill a 3 car nicely but your neighbors may object.

Justin- how would I go about selecting an amp for driving some subs in the shop? I could easily go there.

And I like the fosgate P3’s. Have them in the jeeps.

Matt,
It depends on your goals. If you are looking to just augment your 101s at reasonable levels a home audio type powered 10/12+" sub would likely be enough and super simple to add. If you already have some sub woofers a 'plate' style amp is a good packaging option

Subwoofer Plate Amplifiers

Ensure that your custom built or upgraded powered subwoofer system performs at its best, and includes every convenient and expected feature, with Subwoofer Plate Amplifiers from Parts Express.

www.parts-express.com

Or you can use typical home audio ($$$$$) or pro audio dedicated amplifiers. I like QSC.

Put the sub(s) in one of the corners of your space to get a large acoustic gain. As you probably know sound pressure level to humans is logarithmic, and once past the 'knee' of the curve the gains are diminishing. Although your shop doesn't have low frequency road/tire noise to overcome like your jeep, It is connected to your house and that may incur some 'restrictions'. If you are floor space constrained consider mounting up high at ceiling.

Haha! Me too....

Me and my neighbor have competing portable Bluetooth speakers going and Justin has a stadium setup in his garage!

Keeps me off the streets I guess. Some of the high end portables are pretty impressive for what they are. I use one on the batwing of my motorcycle and it is enough for highway speeds with a helmet on.

 

[rattle_snake]

Received the 15" Dayton subwoofer for the guitar rig and went ahead and installed it although the cabinet is far from complete. In an attempt to not be cheap I bought the correct size hole saw for the wiring terminals. Avoiding use of jig saw, to have perfect circles everywhere.


I have made some decisions on the grill, but still waffling on the colors. Going to put it to use and finish the dual 10 cabinet. Then I can swap out the 10s and finish the 15 which should be quick.

 

[rattle_snake]

18" of badass.
Actually this is a cheap high efficiency woofer. Light weight paper cone, softer spider (for cone dampening/control) but not much excursion. 93 db 1w/m, in comparison the RF P3 10 are 82. 11 db is 12x as loud. A typical professional level 18 is 10x the cost.
The old, clapped-out QSC USA1310 should still be able to deliver ~1000W to it, but I imagine it will reach driver mechanical limit first, no clipping.

 

[SilverJimmy]

So you seem to know all about this stereo stuff, do you know who or where to get woofers re-foamed? I have 4 JBL Control Monitors and the woofer foam has disintegrated in all 4 of them. These are really nice speakers and I’d like to try to save them.

Any recommendations for repair?
Thanks!

 

[SilverJimmy]

Probably need this too!

 

[rattle_snake]

Parts express sells refoam kits.

Speaker Surround Refoam Repair Kits

Discover a second life for your old speakers that have damaged or decomposing cone surround foam. Get back into perfect condition with our speaker surround refoam repair kits.

www.parts-express.com

 

[lilscorpion]

Yes my shrink would agree. It would fill a 3 car nicely but your neighbors may object.

Matt,
It depends on your goals. If you are looking to just augment your 101s at reasonable levels a home audio type powered 10/12+" sub would likely be enough and super simple to add. If you already have some sub woofers a 'plate' style amp is a good packaging option

Subwoofer Plate Amplifiers

Ensure that your custom built or upgraded powered subwoofer system performs at its best, and includes every convenient and expected feature, with Subwoofer Plate Amplifiers from Parts Express.

www.parts-express.com

Or you can use typical home audio ($$$$$) or pro audio dedicated amplifiers. I like QSC.

Put the sub(s) in one of the corners of your space to get a large acoustic gain. As you probably know sound pressure level to humans is logarithmic, and once past the 'knee' of the curve the gains are diminishing. Although your shop doesn't have low frequency road/tire noise to overcome like your jeep, It is connected to your house and that may incur some 'restrictions'. If you are floor space constrained consider mounting up high at ceiling.

Wonder why you think I might have floor space constraints…I do, I’m out. Will have to be on the wall/ceiling but that may be a good choice anyway. If I were to place it at the top of the wall, which can be 14’, how should the sub fire? Do I need more than one firing specific directions? 10”? 12”…what’s optimal?

The shop is a rectangle, near perfectly. 21 wide, 45 long, 14’ high. I can mount on the wall with the dust collection duct b/c it’s exterior. That would be ideal. Only one corner of that wall is exterior…

 

[SilverJimmy]

Thanks for the link on the foam kits. Are they pretty much universal, all the same quality? How much skill/experience is needed to get good results. One of my character flaws is a hesitation to attempt something new, I really hate to not do something well. It’s kinda stupid cuz once I just jump in and do it, it usually turns out good! I know, TMI!

 

[Bob Heine]

Justin, not knowing jack about speakers, I successfully replaced the foam on a pair of Advent speakers six years ago (https://www.garagejournal.com/forum/threads/bob-heines-auto-emporium.319566/post-7617524). It was my first attempt and I found the foam and a decent set of instructions at Simply Speakers. I liked that their website offered the kits by brand. Here's a link to the JBL kits:

JBL Speaker Repair Foam Edge Kits

www.simplyspeakers.com

 

[rattle_snake]

Wonder why you think I might have floor space constraints…I do, I’m out. Will have to be on the wall/ceiling but that may be a good choice anyway. If I were to place it at the top of the wall, which can be 14’, how should the sub fire? Do I need more than one firing specific directions? 10”? 12”…what’s optimal?

The shop is a rectangle, near perfectly. 21 wide, 45 long, 14’ high. I can mount on the wall with the dust collection duct b/c it’s exterior. That would be ideal. Only one corner of that wall is exterior…

The direction of the subwoofer doesn't matter, low frequencies are more or less non-directional. One should be enough. There isn't really an optimal size either. Think of a speaker like an piston engine. It has a bore and a stroke that yield a volume of air it can move, which makes sound. Bigger cone makes more sound for a given stroke but is heavier so needs more power to move it.

Thanks for the link on the foam kits. Are they pretty much universal, all the same quality? How much skill/experience is needed to get good results. One of my character flaws is a hesitation to attempt something new, I really hate to not do something well. It’s kinda stupid cuz once I just jump in and do it, it usually turns out good! I know, TMI!

Not really sure on quality. Not hard to do either.

Justin, not knowing jack about speakers, I successfully replaced the foam on a pair of Advent speakers six years ago (https://www.garagejournal.com/forum/threads/bob-heines-auto-emporium.319566/post-7617524). It was my first attempt and I found the foam and a decent set of instructions at Simply Speakers. I liked that their website offered the kits by brand. Here's a link to the JBL kits:

JBL Speaker Repair Foam Edge Kits

www.simplyspeakers.com

Jimmy, I would steer towards a kit that is specific to the model if possible. Other wise can measure.

 

[rattle_snake]

Stacked up the equipment and made some speaker cables. Unfortunately the amp is back to a failing channel after physically moving it, as I had expected. Not enough gain, some work to do.

 

[lilscorpion]

The direction of the subwoofer doesn't matter, low frequencies are more or less non-directional. One should be enough. There isn't really an optimal size either. Think of a speaker like a piston engine. It has a bore and a stroke that yield a volume of air it can move, which makes sound. Bigger cone makes more sound for a given stroke but is heavier so needs more power to move it.

Ok, I get it, I think. Does sound change with the size of the speaker? Like…dunno, bass is deeper with the larger diameter bigger speaker? I don’t know much about subs, guessing a bigger speaker could handle different frequencies?

 

[PhantomEB]

so Can’t wait for my surgery…..gonna be way nicer to have way more hearing than I do. Maybe then I will appreciate loud music even more, not just loud so I can hear it!

 

[rattle_snake]

Ok, I get it, I think. Does sound change with the size of the speaker? Like…dunno, bass is deeper with the larger diameter bigger speaker? I don’t know much about subs, guessing a bigger speaker could handle different frequencies?

All other things the same no, not for a subwoofer. but yes in general and for smaller drivers. The frequency response for a speaker is dependent on it's free air resonance, Q, and Vas (which is the equivalent amount if air to have the same springyness/damping as the speaker itself). Typically larger, heaver speakers have lower free air resonances.

There is an inverse relationship of low frequency output vs efficiency. Low efficiency can be overcome with more power, and/or multiple drivers.

For your space I would suggest a single 12" driver with 250-500w. Simple sealed box with some attention to vibration isolation in the mounting scheme.

so Can’t wait for my surgery…..gonna be way nicer to have way more hearing than I do. Maybe then I will appreciate loud music even more, not just loud so I can hear it!

Dang man sorry to hear that you suffer from that. Good luck with that surgery.

 

[rattle_snake]

Made a trip to the steel yard and got some materials for speaker grills. For mitered corners the Evo chop saw does a nice job. Hardly any clean up cut cut and weld.


I should probably buy a set of four smaller jigs, but doing one joint at a time seems to work well enough.


Finished out with 1/2"hole perforated 16g


Need to figure out how to best mount them and some paint.

 

[rattle_snake]

I built yet another speaker box for my daughter car. She gets to pick the color/style from here.

 

[OutlawDrifter]

Justin, do you use finish or brad nails? Or are they just glued together?

Still love the rounded off corners, super clean looking

 

[rattle_snake]

One of my newer-to-me GX5 amplifiers went into fault mode. Poo. I had already re-installed the USA1310 in the rack for the 18, so I just hooked it up and pulled the wounded amp out. With 3 broken amplifiers it seems like the right time to invest in an oscilloscope, plus it would arrive on fathers day. For audio use even a 50 Mhz unit is overkill, but have to have 4 channels.

 

[rattle_snake]

Justin, do you use finish or brad nails? Or are they just glued together?

Still love the rounded off corners, super clean looking

They have no fasteners, just glue, which means the router won't ever find one. Glue only takes more time and clamps, but with several project going it's not a block.

 

[rattle_snake]

Received the shipment of goods


New mid/tweet amp for the Cobra. This is class D-ish, but is still physically as large as the class A/B behind it from 25 years ago. Plan is to swap it out for the one with damaged channel that has smoked two tweeters now. No passive filter to save them (aka cap to block DC). Maybe the old can be fixed.

 

[rattle_snake]

A P3 compared to the GRS long throw sub.
Rockford is great at making things look impressive. The frame is not cast, it is stamped and coated to look like cast. And the magnet looks bigger with a rubber cover. Hell, the boxes are gorgeous. Big heavy Mofo made to move a heavy cone in a controlled fashion and not overheat doing it.


I realized at this point that the 10" P3 isn't like a typical 10" driver, it is larger. I wanted to mount them business end out, but the standard 10" cutout of 9-1/8" is too small to clear the surround. Most 10s are 10-1/4" OD, but P3 are 11", and surround is 9-5/8. It still mounts in a 9-1/8 hole, but is not designed to face mount. The flange wasn't intended too and no gasket. It is possible to make an adapter ring of some sort, but seems like a band-aid. Could hog out the holes in the box, but not while it's hanging from the ceiling, and would be a hack. So I just decided to install them in regular fashion and move on with life. I wired the dual 2 ohm coils in series to yield 4 ohms.


Luckily the guy who made the speaker box included terminals for the internal wiring. Not easy to wrestle the beasts in upside down on a ladder. Found out the hole pattern is of a larger diameter. Luckily the holes are blind and won't leak air. Got the drivers installed without damage to me or them.


And how does it perform? About the same as expected. The GRS subs are quite impressive for what the are. They were at their physical and thermal limits for sure. My cost for the P3 was about the same, and the P3s take the power under control and will survive in the long run. After testing the suspected GX5 amp, it was working fine so I buttoned it up and reinstalled it. I did notice that the new 10s need more gain to blend well with the 12s. They are less efficient with smaller radiating surface and in a seal box that has lower output. The difference is significant, ~ 6db aka double. The old tens couldn't handle the extra gain.
I played with a box calculator and designed a vented box that would provide a decent advantage. Perhaps at some point I'll make new boxes. One box is too heavy for how they are mounted. The ports have to be really long to tune box down below 30 Hz. One 4" port isn't really enough for the volume/pressure of the system and will make noise. 2 ports make the port length double. The smaller the box, the longer port needed for same freq. If ports go inside the box, it has to be larger by that amount, which is significant. Hence the giant heavy vented boxes the 12s are in.
Anyhow at full power it's crisp and tight. The suspect amp did fine for hours. I think it went into thermal shutdown before, and its behavior is just odd. I learned more about the GX amps, the are a different flavor than the older class H USA series. The main power transistors are only rated at 150W, 2 in parallel so sustained capacity of 300w, 15A. This is not 700w as rated, however it has +/-125 V rails (250 VDC!) to work with which is huge and delivers the peak/instantaneous voltage and current needed for music without clipping.

 

[rattle_snake]

Taking another swing at fixing CH1 of old amp. It appears to clip early and channel collapses, but recovers when muted. Typical culprit is electrolytic caps on the low voltage rails, but I had already replaced then long ago. I probed the output of the 1st output gain stage and got it into failure mode. The voltage rails should be a constant DC voltage of 14-ish, but they swung wildly, I touched the heatsink and it started working properly again, voltage rails stabilized. From there I scope'd the output of the 1st amp. Back to failing, it was driving the hell out of stage two and hence clipping. When OK, it has a nice clean audio wave. Poking the op amp with scope probes would also fix the problem, but I can't find anything broken. I re-seated the op amp in it's socket and it seems to be working. Threw it back in rack and let loose with the bass guitar. It was OK for a short time but not fixed. but the other (sub) channel works. Engaging the octave effect causes saturation, but cleans up with boost/comp. Together, holy hell does it shake the entire building.

 

[rattle_snake]

I think I have narrowed down the cause of the amplifier issue. Ordered some $0.05 diodes. Put it back together to use the one channel for the 15. Switched the 10s back to the Line6 amp, however the speaker output stops when you plug in headphone/line out plug. Seemed like a good time to take it apart and modify.

Did some experiments to understand how the jack is wired. It uses a detect circuit and the DSP then applies mute to the amps. So I left that alone and tapped into the signal path not effected by inserting a plug.


Ran a mic cable into the box and soldered it to the PCB. Now I have a dedicated line out signal. Ordered a panel mount jack, when I get bored I'll upgrade to that.

 

[rattle_snake]

Mostly finished the guitar cabinets. Decided how to paint and wrap. Went with boring black vinyl, got enough to make it one piece. Painted baffle blue and back black.


Wrapped around the inset back and trimmed, came out nice enough.


Painted the grills satin black and installed


Then I broke down the 15, and went through the process again.




Stacked em up and tried it out. Decent for used/broken/cheap stuff.


Tidied up the wiring and calling it done. Almost, grills need a logo.

 

[rattle_snake]

Went to do boat impeller job and realized I was short an o ring. Noticed the thrust plate is worn out. Then I broke the housing a bit more so have to replace a few more things.

So I pulled my car in the shop to fix the broken stereo system. 1st step was to verify the real underlying issue that killed the tweeters, direct current (DC). Meter read 23 VDC which will smoke any speaker connected to it. Shorted output transistor to power rail. So out the amp came to be replaced. 10 years later, same basic design, exact connector layout. Installed and wired up.


I popped open the damaged amp to see if something was visually repairable. Nope. I **** canned the amp even though 3/4 channels work, not willing to chance more drivers if another channel fails in same way due to same old age/heat. No time spent.


Some of the carpet had come loose over the years so I gave the box some TLC.


Tested one more time for DC in case it was wiring issue, and installed another set of tweeters. RF T2s so just popped them into the existing mounts and wired them up. Fiddled around with levels to get it tuned in and called it a victory.

 

[rattle_snake]

I cleaned the neglected car up, inside and out. I guess I'm getting close to needing rear tires again? I do see treads left still.

 

[OutlawDrifter]

Probably wouldn't be much good in the monsoons!

 

[rattle_snake]

Made some progress on daughters system. Mounted the equipment and ready to test fit. But her car wouldn't start, dry/dead cell in battery. So have to fix that first. Always something.

 

[rattle_snake]

Probably wouldn't be much good in the monsoons!

No, not a monsoon mobile for sure. I run 15 psi in these tires and they seem to wear pretty evenly. Boy do they hook hard with a little heat, same as new.

 

[rattle_snake]

Went ahead and broke the Line6 amp down again to add panel mount jack. Much nicer to have removable cable.


Used the vinyl cutter to make a paint stencil for grill logo. SMG = Speed Metal Garage


Needs to be larger, plan to redo upper grill.

 

[rattle_snake]

Parts for the boat came in, got the sea water pump reassembled and back in. 4 nuts and 2 hoses but none easy to access. I carry a spare impeller and use the tools in the boat, in case I need to service on the water. Swapped in a new fuel seperator/filter and primed the system. Next is outdrive oil change which is a pain in the ***. The hand pump takes 300 pumps, no fun in the bottom of the ditch with bad knees. I bought a cheap 12v oil pump, going to see if it will do the job, have to pump in from bottom so air goes out top.

Also need to fix the vinyl on the engine hatch. I used white duct tape, now I have a ton of goo to remove to try a different product. What's the go-to solvent for this?

 

[PugetDude]

WD-40

 

[OutlawDrifter]

Goo-Gone does a descent job, also I've found Turtle Wax Bug & Tar remover works quite well.

 

[PugetDude]

Also need to fix the vinyl on the engine hatch. I used white duct tape, now I have a ton of goo to remove to try a different product. What's the go-to solvent for this?

Justin, I highly recommend Escobedo's Upholstery on Apache Trail. They have done half a dozen projects for us, good quality and reasonable prices. I intend to have them do the '32 if I ever get that far...