Portable speaker project

Thread Starter

Chaz_the_jazz_man

Joined Oct 30, 2024
5
Hiya I’m making a portable speaker out of an old radio shell, anyone know of some really good speaker drivers for the build? I’ve heard Dayton audio has a good selection but there’s a lot to choose from. Thanks !
 

LowQCab

Joined Nov 6, 2012
5,101
The Internal-Volume of the "Shell",
and whether or not it is practical to completely "seal" that "Shell" will be
the determining factors as to how much Fidelity that You can expect from this project.

Please include the dimensions of the "Shell".
Please include several pictures.

What type of "Listening-Content" do You expect to play through this Speaker ?

Do You have Carpentry-Skills and Tools ?

Bigger is always better.

If the Back of the "Shell" is destined to remain forever open,
the Bass-Response will range from funky and poor, to basically non-existent,
( mostly below ~150Hz ),
but there is a simple trick to getting around this dilemma, and delivering respectable, clean, Bass.

High-Fidelity-Speakers are generally not very efficient,
how much Power do You have to drive the Speaker ?,
and what type of area do You expect to cover ?,
and with how much Volume ?

Speaker-Placement in a room can make a massive difference to the end result.

If High-Fidelity is desirable to You,
would You consider adding a Sub-Woofer buried somewhere in the corner of the room ?
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MisterBill2

Joined Jan 23, 2018
27,507
As a (non-serious) comment, I have seen current large screen televisions advertised as having "Giant" 2 1/2 inch woofer speakers. So, depending on one's imagination, good bass response may be possible. At some sound pressure level much less than 82 Decibels.
 

MrChips

Joined Oct 2, 2009
34,807
Depends on the audio power, size and weight you seek in a portable amplifier. Are you busking with a bass guitar or just playing recorded music?

I built a portable bass amplifier using a 200 W automotive bridged amplifier with a 10" speaker, running off a 12 V SLAB.

bass amp.jpg
 

Thread Starter

Chaz_the_jazz_man

Joined Oct 30, 2024
5
Thank you all for your super insightful responses!

I’ll clarify for those who asked :

The project is going to be your typical Battery powered Bluetooth portable speaker meant for playing music on the go.

the housing will be an old radio we’ve had in the family for a while, dimensions are around 27 cm long 18 cm high and 11 cm deep. Once I get home I’ll post photo’s

in terms of power I think 30W is easily enough for normal volume settings, if not too much.

because of the limited space it would easier to have 1 full range speaker rather than high and low with a crossover.

in terms of electronics, though I could design an amplifier myself, I don’t have enough time so I’ll leave that for another project, I have found an okay kit that includes battery pack and amplifier modules all ready to be mounted. You can find the reference here . If anyone has any alternative recommendations I’d be happy to hear them !

And adding a little extra info, this project is meant to be a birthday gift for a family member :)
 

Thread Starter

Chaz_the_jazz_man

Joined Oct 30, 2024
5
Thank you all for your super insightful responses!

I’ll clarify for those who asked :

The project is going to be your typical Battery powered Bluetooth portable speaker meant for playing music on the go.

the housing will be an old radio we’ve had in the family for a while, dimensions are around 27 cm long 18 cm high and 11 cm deep. Once I get home I’ll post photo’s

in terms of power I think 30W is easily enough for normal volume settings, if not too much.

because of the limited space it would easier to have 1 full range speaker rather than high and low with a crossover.

in terms of electronics, though I could design an amplifier myself, I don’t have enough time so I’ll leave that for another project, I have found an okay kit that includes battery pack and amplifier modules all ready to be mounted. You can find the reference here . If anyone has any alternative recommendations I’d be happy to hear them !

And adding a little extra info, this project is meant to be a birthday gift for a family member :)
A little extra extra info, my budget is limited but flexible, around 200€ would be good though if quality requires more I’m willing to up the allowance
 

Thread Starter

Chaz_the_jazz_man

Joined Oct 30, 2024
5
Depends on the audio power, size and weight you seek in a portable amplifier. Are you busking with a bass guitar or just playing recorded music?

I built a portable bass amplifier using a 200 W automotive bridged amplifier with a 10" speaker, running off a 12 V SLAB.

View attachment 334790
Sick build ! how’s the SNR on that thing ? Also how would you reduce noise when playing at a louder volume? I have an old fender supersonic 22 combo that needs fixing if you have any tips :3
 

LowQCab

Joined Nov 6, 2012
5,101
Regardless of what You choose for an Amplifier, make sure that it's "Class-D",
they are way more efficient.

10" X 7" X 4" Hmmm, awfully small to also contain a Battery ..........

What are the dimensions of the original Speaker-cut-out ?,
what type of material is the Cabinet made of, maybe Bakelite ?,
what year of manufacture ?,

First guess at Speaker that "might" fit the Cabinet.
If it's practical to seal the back of the Cabinet, and leave a specifically sized hole in it,
this Speaker will give excellent results down to ~45Hz.
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MisterBill2

Joined Jan 23, 2018
27,507
Except for the shipping cost, I can make somebody a great deal on a pair of Electro Voice speakers in the original EV enclosures. Never abused.
And 25 years ago I got a fantastic deal on used 100 watt and 50 watt PA amplifiers, all I could get in my car for free. So far rge worst problem I came across was a broken gain pot. The other problem on another was a broken power switch. I have given a few to folks who could not buy them. They are good enough for casual music at moderate sound levels, and they can produce the sixties distortion when driven way too hard.
 
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BobTPH

Joined Jun 5, 2013
11,515
this Speaker will give excellent results down to ~45Hz.
Not in that enclosure. 45 Hz was given for a tuned, ported enclosure or .38 cu ft. That enclosure is .16 cu ft based in the outside dimensions, the walks themselves and the volume of the speaker must be subtracted. So you maybe have a little more than .1 cu ft.

I have built speakers that do go down to 45 Hz using a 6 in woofer. They are much larger (.86 cu ft.)
 

skstrobel

Joined Nov 29, 2023
28
Something like the AK-370 or AK-380 has the Bluetooth interface, amplifier and tone controls all built in for around $25 to $35 at Amazon (less at AliExpress if you can wait for delivery). The 12V power input is normally driven by a wall wart, but you could use a battery. I have the AK-170 (similar, but no Bluetooth) driving a pair of in-wall speakers. That combo certainly isn't hi-fi, but it is better than most Bluetooth speakers and plenty loud.

If you have extra room in your budget, you'll probably get a better return on higher quality speakers than on better electronics. It would also help the audio quality if you can mount the speakers in a rigid box (perhaps inside the radio shell). If you have to use the thin plastic shell as the speaker cabinet, it might help to epoxy some cross braces to keep the sides from resonating as much and to stuff some fiberglass insulation or polyester fiberfill inside to minimize reflections.
 

Thread Starter

Chaz_the_jazz_man

Joined Oct 30, 2024
5
hiya, a bit late with the photos but here they are. I was a bit off with the size guesstimates it’s more around 30cm by 17cm by 8cm.

it’s an old Robert’s R606-MB the housing is mainly wood, with bits of metal.

IMG_1158.jpegIMG_1155.jpeg
 

LowQCab

Joined Nov 6, 2012
5,101
Were did they put the Tubes ????

This changes things substantially.
The Speaker that I previously suggested is no longer workable at all.

Zero Bass, not appropriate for music. Talk-Radio maybe.

I'm sorry, but I'm afraid this project will be a disappointment.

Adding "Plug-in Power", combined with tons of EQ,
might make it sorta passable in that Box.

See what You can find in a Pawn-Shop that's at least twice as big in every dimension,
and preferably made of wood,
You might be surprised at what You can find.
An Electric-Guitar "Practice-Amp" Cabinet might be a good start.
Or even a small Automotive "Sub-Bass" Cabinet, ( there will be plenty of these in a Pawn-Shop ).
This will also make it easier to install 2-Speakers for Stereo instead of Mono.

Without a decent Cabinet, You might as well just use Ear-Buds.

A pair of small "Bookshelf" Speakers laid on their sides and with their bottoms screwed together would work great, ~$50.oo.
These are also available with a built-in Amp, with a USB-Input, but they are much more expensive.
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