A better speaker for my new toy...?

starhawk

[H]F Junkie
Joined
Oct 4, 2004
Messages
8,908
Bought this recently --> http://www.ebay.com/itm/201004070756

It has a built in speaker. That's the main reason I bought it -- I wanted to see how they did that, along with how it's controlled (etc). The sound is tinny and a bit buzzy. Probably can't do much for the buzz (internal amp chip is a SMT version of the LM4871 that I really don't feel like replacing, and there's not really any room for piggying in extra components...) but the tinny speaker I might be able to fix.

What's in there now is a little oval thing that looks like you'd find it in a cheap old cell phone. The upshot is that it's on leads. I can replace that!

...but is there a cheap, small speaker that will fit this thing, that I can stuff in there?

I'll post photos of the player and its guts in a little bit, got a phone call to make first.
 

Skripka

[H]F Junkie
Joined
Feb 5, 2012
Messages
10,792
I'm not at all certain you can improve on such a thing.

There's a reason every small portable handheld device with speakers in it known to man sounds small tinny (headphones aside as they are not intended to be listened to from more than a centimeter away from the cone). Because the speakers are small...and the device it is in is either plastic or metal.
 

starhawk

[H]F Junkie
Joined
Oct 4, 2004
Messages
8,908
This device is both plastic and metal. It has a small plastic frame and a metal body around that.

I'd like to fit a bigger speaker in there. In the pictures below you'll see a silkscreen speaker outline, it's about 25mm in diameter although the jog-switch for play/pause and track-skip seems to protrude into that. I'd say a 20mm (ish) diameter speaker, with a 2mm thick 'wide part' (cone housing -- sorry, not up on the latest audiophile terminology :eek: ), would fit just fine. I realize that it's not going to get /significantly/ less tinny, but improvement is improvement, you know?

...actually, probably the buzziness of the speaker is partially cuz it's just hanging there with nothing to hold it in place. They basically cut a hole in the PCB and said "oh hey let's stuff the speaker in here". Hm.

EDIT: clicked submit and immediately realized I'd left something out -- the size. The grid paper you see in the photos, is ten-square-per inch paper. There's a slightly thicker outline for squares that are one inch in size. This thing is TINY!

Large pictures:
http://i.imgur.com/IheR7OX.jpg
http://i.imgur.com/HvDbvGD.jpg
http://i.imgur.com/PtarFBM.jpg
http://i.imgur.com/4R8nqdX.jpg

Pictures:



 

Mohonri

Supreme [H]ardness
Joined
Jul 29, 2005
Messages
5,751
You *might* be able to find a larger driver that would fit, with the coil going through the hole and the horn resting on top of the PCB. It's kinda hard to tell how much clearance you have on top of the PCB (between the PCB and the outer case).
 

starhawk

[H]F Junkie
Joined
Oct 4, 2004
Messages
8,908
'horn' is the word I was looking for -- I was thinking exactly the same idea, put the coil in the hole and the horn on top. The horn definitely can't be more than 2mm thick, and thinner would be better...
 

Mohonri

Supreme [H]ardness
Joined
Jul 29, 2005
Messages
5,751
With that thickness, you'll probably be limited to headphone drivers. Hey, didn't you have a pair that you ripped apart a while back for some sort of magnet project?
 

starhawk

[H]F Junkie
Joined
Oct 4, 2004
Messages
8,908
Nope. That wasn't me...

What about the little mylar cone jobs at Mouser and the like? My local Radio Shark (a franchise store with a wonderful owner who has the same attitude I do about the whole place) stocks that sort of crap... I checked and the one in the player is 8ohms...

...or are those tinny like a Campbell's can as well? (I'm guessing so -- the ones at my RS look straight out of an overly noisy greeting card...)
 

dandragonrage

[H]F Junkie
Joined
Jun 5, 2004
Messages
8,298
I'm not at all certain you can improve on such a thing.

There's a reason every small portable handheld device with speakers in it known to man sounds small tinny (headphones aside as they are not intended to be listened to from more than a centimeter away from the cone). Because the speakers are small...and the device it is in is either plastic or metal.

Exactly. Like many people say about engines, "There is no replacement for displacement." The same applies to speakers.

For those who might want to learn more, research "Hoffman's Iron Law"

The enclosure is at least as important as the driver (driver = "raw speaker" as opposed to a speaker system). Always match the speaker to the enclosure.
 

starhawk

[H]F Junkie
Joined
Oct 4, 2004
Messages
8,908
I think I get it.

I'm not an audiophile. I just want something that isn't insultingly bad.

Can I at least have that, out of this thing?
 

dandragonrage

[H]F Junkie
Joined
Jun 5, 2004
Messages
8,298
I'm not an audiophile. I just want something that isn't insultingly bad.

Can I at least have that, out of this thing?

I don't have a good enough idea of your expectations. I'm going to say probably not. What're the dimensions of it? Looks to me to be around 3"x4"x0.75" (if not a bit smaller), with most of that space being taken up by electronics and the case itself?

I'd say you can probably get this thing to sound a bit better than most cell phones, but not by a lot.

I don't know if the thing has a highpass filter (can't see most of the board in your pics and would need a high-res version to tell) but if not, adding that should fix much of the buzz. For a speaker that small, it would probably have to be in the 150Hz area (which sucks, but nothing that small can really do better).

In any case, the best source for this sort of thing is probably going to be Parts Express, since they have a lot of inexpensive speaker drivers and a lot of oddly-sized ones too. www.parts-express.com
 
Last edited:

starhawk

[H]F Junkie
Joined
Oct 4, 2004
Messages
8,908
As mentioned before, a speaker with a horn ~20mm in diameter (+2mm max/-whatever) and not more than 2mm thick (probably 1.5mm would be better) would fit. More than that, will be problematic.
 

dandragonrage

[H]F Junkie
Joined
Jun 5, 2004
Messages
8,298
As mentioned before, a speaker with a horn ~20mm in diameter (+2mm max/-whatever) and not more than 2mm thick (probably 1.5mm would be better) would fit. More than that, will be problematic.

Well, you can give it a try. Nothing you could put in there would satisfy me enough to pay any amount of money for it, but I'm a snob. Like I said, we don't have a clear idea of your expectations.

Do you know if there is a highpass filter? It has more power than a cellphone but it sounds to me like the biggest issue is probably lack of one. If you put any bass into that without it being filtered to a significantly lower level, you're likely to bottom out the suspension of any tiny driver.
 
Last edited:

dandragonrage

[H]F Junkie
Joined
Jun 5, 2004
Messages
8,298
I suppose you could put a voltmeter across the speaker and a voltmeter across the input and run some test tones and measure the frequency response (or hook it back up to your line in with some resistors and run a sweep with certain software that can measure it.

Otherwise it'd take a bit of deciphering of the circuit.

I imagine it might not be worth either of those things to you.
 

starhawk

[H]F Junkie
Joined
Oct 4, 2004
Messages
8,908
Not really, and the speakers at Radio Shack are not going to be cheap.

Might see what eBay has in the way of dinky speakers, but I'm actually losing my enthusiasm for this...
 

starhawk

[H]F Junkie
Joined
Oct 4, 2004
Messages
8,908
I thought about piezo -- but IIRC they have a far far lower resistance (and therefore are a lot louder) than a real speaker. This thing already kinda rails its speaker... meaning a piezo doohickey would probably bust flat in half... and kill my ears at the same time!
 

starhawk

[H]F Junkie
Joined
Oct 4, 2004
Messages
8,908
Just to wrap this up... took the player to a friend of mine and he put in a cell phone speaker, of all things. Worked out OK... it no longer gives me visions of Campbell's Tomato Soup when I listen to it... it's still tinny, but it's not /painfully/ tinny, so I guess I'm happy.
 
Top