Reverse tool box design

[NealCain]

I do not know anything about audio electronics so to have any chance for decent sound quality I am going to need help.
My idea is for something like the ammo box kit on PE - bluetooth , battery powered and portable but also adding a woofer using the TPS3116D2 Class D 2.1 Bluetooth 4.0 Amplifier Board and stealth.
I have already built the box and these are the internal dimensions of my tool box - ID 14 3/4L X 7 1/4W X 7 3/4H.
Also I would prefer to not cut the tool box and keep controls/speaker mounted on the MDF. Top mounting dim - 14 3/4 x 7 1/4 and side mounting dim - 14 3/4 x 5 1/2. Take a look at the pics and you will see what I mean by control/speaker mounting areas.

This project means a lot to me so I am grateful for your advise

[a4eaudio]

Google search for Paul Carmody's Isetta speaker. The dimensions look close enough to yours to work. However, you will need a port which may require you to cut at least one whole in the tool box. You might be able to rearrange the speakers enough to get the port and controls all on the top.

[NealCain]

Thanks a4eaudio, that was a good read. On the list of part is the Fountek FE85 which is no longer available, what would be a good substitute?

[NealCain]

I randomly picked these on PE as a possible replacement Tang Band W3-881SJ 3" Cast Frame Neodymium Driver and Tang Band W3-881SJF 3" Full Range Speaker. They are more expensive so they must be better....right.=) Any thought on these speakers?

[a4eaudio]

The problem is that Paul C. has designed a nice little crossover that will "shape" the response of the FE25 better than the raw speaker would produce on its own. If you pick another driver it is unlikely that you can just drop it inti his crossover. BUT...you could just pick any 3" full range driver, run it with a simple 2.1 amplifier module with the same woofer and probably be okay for a boom box build. I saw a recent recommendation for this driver...Tang Band W3-593SF...supposedly it sounds very nice.

Edit: But, if it were me I would find the FE25's on Amazon, Ebay, Aliexpress, etc. and build the Isetta.

[NealCain]

OK I am starting to "get it"... The Paul crossover is the special sauce for the FE25. Um how do I get his crossover?
What about the AMP? I was thinking of using the TPS3116D2 Class D 2.1 Bluetooth 5.0 Amplifier Board 2 x 50W + 100W with Filter and Volume Controls.
Also the sub will be 1/4 inch to big to mount on the face so think of mounting the speakers on the face and sub on top.

Thanks for the Q&A

[a4eaudio]

OK I am starting to "get it"... The Paul crossover is the special sauce for the FE25. Um how do I get his crossover?
What about the AMP? I was thinking of using the TPS3116D2 Class D 2.1 Bluetooth 5.0 Amplifier Board 2 x 50W + 100W with Filter and Volume Controls.
Also the sub will be 1/4 inch to big to mount on the face so think of mounting the speakers on the face and sub on top.

Thanks for the Q&A

His crossover is a little more than half-way down the page in the Section "Filter and Electronics", right below the "Driver Selection" section. It has 4 components (a resistor, inductor and two capacitors) and he briefly describes what it does and why he thinks it is worth the trouble.

I think almost any inexpensive 2.1 board with Bluetooth will be fine, unless you went with something crazy cheap, shipped from China, off Amazon or Ebay, of questionable quality.

Also...if you will be running off of batteries you will not be getting 2x50w+100w. With a 12V power supply you will get a LOT less power than if it is plugged in to a power supply with closer to 24V, which is the max it can handle. But that is true of all the battery powered boards at 12V, nothing unique to this particular one.

[Wolf]

I saw a recent recommendation for this driver...Tang Band W3-593SF...supposedly it sounds very nice.

Just look up the notch filter for the w3-871, and be happy. If you can't find it, I know a guy....
Wolf

[NealCain]

This is where my thinking is at... Due to the restriction of the metal enclosure I am putting the sub on top and the drivers/amp/controls on the face.
This is my parts list so far: TPS3116D 2X50+100 AMP , LBB-5 5X26650 charging board , TB W5-1138MF 51/4 SUB, 24V power supply , 2.5 DC jack , 11/8x6 port (as closet to the 1.5x10.5 on PE as I could find)
As for the driver I have a pair of Alpine SPS-410 4 inch coaxial 2-way speakers and wondering if these would make for a better substitute driver? Specs: 3/4 tweeter , 86dB , 97-22k Hz , RMS 45w , peak 140w. Bigger is better...right.HEHE!
If the FE25 are better than I will stick to that.

Thanks for your considerations

[NealCain]

Good from far, far from good.
Posting my results. Having no carpenter skills or audio skills I learned a lot. It took longer than I though and was more difficult to build but was FUN! The sound quality was medium at best, drivers sound good but the sub is very muffed/muted. Sub sounds like some kid driving next to you with subs basting, not clean. Guessing the repositioning of the sub and different port tube had to do with it. It would be great to listen to someone else's build to compare sound.
I think it came out well so I give myself a B for aesthetics.

[djg]

Very nice. You might want to placard the port and subwoofer, "Not an ashtray".

[Steve Lee]

:D

"Not an ashtray".

[NealCain]

Any ideas on why the base is so poor, changes to make or things to check?

[Chris Roemer]

Your L/R channels should be internally "walled off" from the sub's internal volume.
If you can tell me (close to) "exactly" how much internal volume the sub has to work with, and the dims of the port you used (1-3/8" id x 6" long?), I'll tell you what your sub "system" is tuned to (and offer suggestions).

[a4eaudio]

If there is not a separate enclosure for the subwoofer driver, that has o be fixed first. Second... Did you chamfer behind the driver at all?

[NealCain]

Yes I build enclosure for the drivers and these are the subwoofer measurements - 14 3/4 x 4 3/4 x 7 3/4 + 5 1/4 x 2 1/2 x 7 3/4 with a Port Tube 1-1/8" ID x 6-1/2" L Flared.

[Chris Roemer]

Adding your 2 sub "sections" together, I get 0.37cf (which is WinISD's "default" vented box size for that driver), and your vent should tune that volume to the low 30s (within a Hz or 2 of the design "target" - certainly not far enough "off" to be audible). If your bass seems weak, and you can't get the 30-40Hz range "up" enough to your liking (by increasing the level of the sub, or maybe rolling off the top end a bit lower?), possibly your amp just doesn't operate very well below 40-50Hz?