Through my job I have come across a bunch of little computer speakers that I can have if I want. Oh boy! Making sound in the office! Or the bedroom! Maybe the basement! You see how I work here.
So I'll include pics of the drivers. The group of appearantly similar Harman / Kardon speakers actually had 2 different kinds of drivers.
The ones on the left have printed on the back:
Samsung
08G11ARH
4 (ohm) 3 w
H309 24
On the right:
004-02
4 (ohm) 5 w
China
2J14D
Can anyone tell me anything about these drivers? After some listening the Chinese one sounds like it has more bottom end and more top end, and greater clarity as well. But it is more forward and harsh sounding than the Samsung unit, which sounds mellow, if indistinct. The Chinese unit might be a bit louder. The dustcap on the Chinese unit is hard, shiny plastic, while on the Samsung it's softer, and a matte finish. This is the main visible difference.
While I had the speakers open I had a look at the amp. The central bit of it was a Philips chip, TDA1517P. I didn't have much difficulty finding an online data sheet on the chip, with a reference design. I plan to yank the chip and rebuild it as an exercise. Can any of the smarties around here possibly suggest improvements on the reference design? It's so simple, it makes me think it leaves something undone...
As far as speaker enclosures go - I'm interested in back-horns at the moment. Ones small enough for cheap experimentation and easy placement. If you look up "Makizou" here at diyaudio you'll find the design I'm thinking of. (evidently it's not strictly a horn, but I'll call it that for lack of a better term) I have no idea if these drivers would be appropriate for that (or any) horn enclosure. I see people talking about horn designs as if it's worth a shot sticking any driver in one, but I don't really know what I'm talking about here, so I'd appreciate some input.
Failing that, maybe a multiple FR driver array...?
So I'll include pics of the drivers. The group of appearantly similar Harman / Kardon speakers actually had 2 different kinds of drivers.
The ones on the left have printed on the back:
Samsung
08G11ARH
4 (ohm) 3 w
H309 24
On the right:
004-02
4 (ohm) 5 w
China
2J14D
Can anyone tell me anything about these drivers? After some listening the Chinese one sounds like it has more bottom end and more top end, and greater clarity as well. But it is more forward and harsh sounding than the Samsung unit, which sounds mellow, if indistinct. The Chinese unit might be a bit louder. The dustcap on the Chinese unit is hard, shiny plastic, while on the Samsung it's softer, and a matte finish. This is the main visible difference.
While I had the speakers open I had a look at the amp. The central bit of it was a Philips chip, TDA1517P. I didn't have much difficulty finding an online data sheet on the chip, with a reference design. I plan to yank the chip and rebuild it as an exercise. Can any of the smarties around here possibly suggest improvements on the reference design? It's so simple, it makes me think it leaves something undone...
As far as speaker enclosures go - I'm interested in back-horns at the moment. Ones small enough for cheap experimentation and easy placement. If you look up "Makizou" here at diyaudio you'll find the design I'm thinking of. (evidently it's not strictly a horn, but I'll call it that for lack of a better term) I have no idea if these drivers would be appropriate for that (or any) horn enclosure. I see people talking about horn designs as if it's worth a shot sticking any driver in one, but I don't really know what I'm talking about here, so I'd appreciate some input.
Failing that, maybe a multiple FR driver array...?
Wow have I ever been there! Currently I have computer speakers in 1 place: under my bench, to test something with a plug-out (cd player, sound card etc.) and as a general kickaround test sound setup. Everything else has 2.1 component setups. Unless volume and quality are low you will quickly find yourself wanting better speakers. My advice for myself, in your shoes, would be this:
do a low-to-moderate amount of work on these (likely to be poor) drivers, for learning and fun. Do not go overboard on finishing the completed parts. Do not make any permanent modifications to anything you or your SO care about to install this stuff.
If it blows up, laugh.
do a low-to-moderate amount of work on these (likely to be poor) drivers, for learning and fun. Do not go overboard on finishing the completed parts. Do not make any permanent modifications to anything you or your SO care about to install this stuff.
If it blows up, laugh.
Yeah, the ones on the right look familiar. Like the ones found in Diamond Multi Media desktop speakers. 3" go ok in little QWTLs. Don't expect high spls but can give surprising results for the size.
The little amp will probably have BSC built in. If you put them in new boxes, and keep the width of the plastic boxes, the BSC is done.
Good fun for a wet weekend.
Geoff.
The little amp will probably have BSC built in. If you put them in new boxes, and keep the width of the plastic boxes, the BSC is done.
Good fun for a wet weekend.
Geoff.
The Samsung drivers you mentioned look and sound quite similar to those I ripped out of my old pair of Creative PC speakers. Mine have a smaller magnet and no mounting flange at all. I'm experimenting with them in 3 foot PVC pipes. They sound surprising for their size. Bass does not rock out, but easy listening is good.
How many have you got?
You mentioned line arrays.
I got that deal at Parts Express last year or so on the
50 centers from Pioneer. I built one sample of 8 drivers in the
line.
But you are talking desktop here.
Try a listen with open backs on these small ones. I'm saying a small box with an open back, not some flat board arrangement. If the
enclosure has to be small, a recommended project from Speakerbuilder
used a small driver (and one design in pairs) with a small angled
box and only a scrim (fabric to prevent dust) on the back.
This works if you don't like the 'boom box' sound so common in
shelf systems. I think there's some loading from the wall in such
an arrangement as well.
Years ago GM told me in these forums to knock the backs off of
some mini desktop speakers to clean up the sound. that's pretty much where I started the hobby.
You mentioned line arrays.
I got that deal at Parts Express last year or so on the
50 centers from Pioneer. I built one sample of 8 drivers in the
line.
But you are talking desktop here.
Try a listen with open backs on these small ones. I'm saying a small box with an open back, not some flat board arrangement. If the
enclosure has to be small, a recommended project from Speakerbuilder
used a small driver (and one design in pairs) with a small angled
box and only a scrim (fabric to prevent dust) on the back.
This works if you don't like the 'boom box' sound so common in
shelf systems. I think there's some loading from the wall in such
an arrangement as well.
Years ago GM told me in these forums to knock the backs off of
some mini desktop speakers to clean up the sound. that's pretty much where I started the hobby.
Anythig that can produce enough heating power, over a wide area. I use a gas stove in my garage and open both doors that open to the outside....
Heat it till it is really soft and hot and squeeze till cold (you can cool with water...).
I used two mdf pieces the size of the outline of the driver and drilled a hole through it (and the enclosure) when reasonably hot and soft I apply it with a wing bolt and voila! A nice flat piece in the middle of all roundness
you can saw out the hole for the driver later (when cool)
Good luck, and don't burn yourself...
And beware not to heat too close with the flames of a stove, it leaves ugly markings on the PVC (which you CAN sand and paint afterwards... ) Just keep the material moving and feel when and how it gets soft...
Heat it till it is really soft and hot and squeeze till cold (you can cool with water...).
I used two mdf pieces the size of the outline of the driver and drilled a hole through it (and the enclosure) when reasonably hot and soft I apply it with a wing bolt and voila! A nice flat piece in the middle of all roundness
you can saw out the hole for the driver later (when cool)Good luck, and don't burn yourself...
And beware not to heat too close with the flames of a stove, it leaves ugly markings on the PVC (which you CAN sand and paint afterwards...
) Just keep the material moving and feel when and how it gets soft...
Progress Report:
So initially the computer speakers sounded terrible. No suprises there. I opened the enclosures and they were hollow plastic echochambers that bonged when you hit 'em. So I stuffed some dampening in. That didn't help, but it was just a thought.
I mounted the drivers on an open baffle to take a listen. This started to show a little promise, but man! At the attack of every note it was like someone was driving a spike into my head! Painful to listen to.
I had noticed the baskets had a distinct *ting* to them when struck, so I decided to damp that. Epoxy putty around the basket / magnet junction, and rope caulk all over helped significantly. Now in the open baffle I wouldn't call the sound awesome, but it is distinctly listable. They're still a bit fatiguing, if you get the volume up, but I was able to enjoy music from them. The gameboy remix of Beck's e-pro really made me smile - musical video game bleeps and bloops sound great on cheap speakers with no bass! And really, I've heard much worse.
So remaining things to try include some PVA glue on the cone, also I've heard about making a little hole in the dustcap (this from the NSB speakers a while back). I had considered a bit of felt or something on the dustcap when the speaker was still driving me crazy, but now that it sounds better I think such drastic measures can be avoided.
After that it'll be time to make an enclosure! Whee!
So initially the computer speakers sounded terrible. No suprises there. I opened the enclosures and they were hollow plastic echochambers that bonged when you hit 'em. So I stuffed some dampening in. That didn't help, but it was just a thought.
I mounted the drivers on an open baffle to take a listen. This started to show a little promise, but man! At the attack of every note it was like someone was driving a spike into my head! Painful to listen to.
I had noticed the baskets had a distinct *ting* to them when struck, so I decided to damp that. Epoxy putty around the basket / magnet junction, and rope caulk all over helped significantly. Now in the open baffle I wouldn't call the sound awesome, but it is distinctly listable. They're still a bit fatiguing, if you get the volume up, but I was able to enjoy music from them. The gameboy remix of Beck's e-pro really made me smile - musical video game bleeps and bloops sound great on cheap speakers with no bass! And really, I've heard much worse.
So remaining things to try include some PVA glue on the cone, also I've heard about making a little hole in the dustcap (this from the NSB speakers a while back). I had considered a bit of felt or something on the dustcap when the speaker was still driving me crazy, but now that it sounds better I think such drastic measures can be avoided.
After that it'll be time to make an enclosure! Whee!
Re: Progress Report:
I find myself in exactly the same situation. I think I have an identical pair of the samsung -based speakers with internal Philips chipamp. Did you take this any further ? I had planned to build some needles, I might try these drivers in them before orderering some Visaton FRS8 s
AdamThorne said:
I find myself in exactly the same situation. I think I have an identical pair of the samsung -based speakers with internal Philips chipamp. Did you take this any further ? I had planned to build some needles, I might try these drivers in them before orderering some Visaton FRS8 s
I've got needles with the recommended drivers (TB W3-871s) in them, and I like 'em a bunch. Lots of people have made the needles with other drivers and nobody has bemoaned the effort that I know of. I guess the enclosure is pretty flexable as far as driver choice goes, but YMMV.
Personally, I tried a random enclosure with the computer speakers and it didn't work. Not very suprising, considering I had no idea of the driver parameters.
Recently I picked up the Parts Express WT3 USB woofer tester. I did quick and dirty tests on the drivers just holding them in my hand, and found the two varied significantly. One set had a resonant frequency of up around 200 hz. The other set was better, at 115 or so. If I recall correctly. I don't remember which was which.
There's a thread I'm watching somewhere around here on correct woofer testing. I imagine myself putting some effort into learning to test drivers with a bit of accuracy, then making a little box for some of these. I even imagine trying out BudP's enable process on them, since he specifically said that testing the procedure with cheapo speakers was a good idea. But the way things are going that might not happen for a while.
If time and my memory permit I'll post the (poorly measured) parameters from the samsungs after work this evening, but you have to promise to let me know if you get anywhere with 'em!
Personally, I tried a random enclosure with the computer speakers and it didn't work. Not very suprising, considering I had no idea of the driver parameters.
Recently I picked up the Parts Express WT3 USB woofer tester. I did quick and dirty tests on the drivers just holding them in my hand, and found the two varied significantly. One set had a resonant frequency of up around 200 hz. The other set was better, at 115 or so. If I recall correctly. I don't remember which was which.
There's a thread I'm watching somewhere around here on correct woofer testing. I imagine myself putting some effort into learning to test drivers with a bit of accuracy, then making a little box for some of these. I even imagine trying out BudP's enable process on them, since he specifically said that testing the procedure with cheapo speakers was a good idea. But the way things are going that might not happen for a while.
If time and my memory permit I'll post the (poorly measured) parameters from the samsungs after work this evening, but you have to promise to let me know if you get anywhere with 'em!
AdamThorne said:
Thanks Adam, much appreciated. My drivers are both the same i.e the speaker with the chip amp and the passive speaker both use the same Samsung driver as one of yours. Hope it's the better measuring one.
I fancy building entirely from scrap as the MDF is off cuts from a bedroom furniture project currenlty underwway, and I have glue and wadding. If I use the Samsung driver then all I need to buy are a couple of pairs of binding posts, and I can always upgrade to better drivers (hopefully use the same screw holes
Here's what I got:
driver 1 2
Re 3.131 3.403 ohms
Fs 135 122 hz
Qts 1.101 1.066
Qes 1.328 1.288
Qms 6.448 6.194
Le .0789 .0942 mH
Mms 1.845 1.963 grams
Vas .0546 .0626 cu ft
sensitivity both ~89 db
Like I said, these were measured with me just holding the drivers in my hand. Testing was less than rigorous. Perhaps I'll manage to do a better job after Thanksgiving...
A
driver 1 2
Re 3.131 3.403 ohms
Fs 135 122 hz
Qts 1.101 1.066
Qes 1.328 1.288
Qms 6.448 6.194
Le .0789 .0942 mH
Mms 1.845 1.963 grams
Vas .0546 .0626 cu ft
sensitivity both ~89 db
Like I said, these were measured with me just holding the drivers in my hand. Testing was less than rigorous. Perhaps I'll manage to do a better job after Thanksgiving...
A
Hi , I don't want to discourage you , but..
Having read the rest of the thread (btw , I feel for v-bro's works), that would put you in the right direction. Better having two -at least- 4" drivers than 100
2" ones , don't matter of which quality. Those are sacrificed drivers: no good for low frequency reproduction ,low power, low efficiency , low impedance...
low! At least you can make closed dipoles with couples , but nothing more.
By putting them in a series-parallel configuration it will add several distortions,not to mention...ok,ok,I'll stop.
Good luck!
Having read the rest of the thread (btw , I feel for v-bro's works), that would put you in the right direction. Better having two -at least- 4" drivers than 100
2" ones , don't matter of which quality. Those are sacrificed drivers: no good for low frequency reproduction ,low power, low efficiency , low impedance...
low! At least you can make closed dipoles with couples , but nothing more.
By putting them in a series-parallel configuration it will add several distortions,not to mention...ok,ok,I'll stop.
Good luck!
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