Hi all,
I hope that someone could help me in setting up this project.
First of all, some history...
in the '90 i got a boombox with detachable speakers (guess it was a Grundig) which served me as a music source in the car and going around.
Despite the poor materials, the sound was nice (not HF, of course!
).
After some years, the whole electronics were stroke by a thunder while wired to the electrical circuit of my house, surprisingly, the plastic closed-cabinet, 2-way speakers seemed be alive and to work well, still.
I trashed all
and saved the drivers and the crossovers (not the boxes, I hated the plastics) for some possible future use.
More recently I bought a cheap commercial t-amp to drive a couple of loudspeakers for the computer. The system sounds fine, but the loudspeakers now in use are definitely too big for my desktop. It is time to make a new "dress" for the old boombox drivers!
So, this is the end of the history and the beginning of the thread:
How to build a decently sounding mini-cabinet for a couple of 2-way drivers, of which I do not know any data at all except dimensions, nominal power and impedance? The whole thing using some MDF or plywood panels at my disposal, elementary tools (jigsaw, soldering stuff and little more) and very very little money?
Closed cabinet is for sure the easiest box to build (I more or less remember dimensions of original plastic boxes), but I'd rather prefer a bass-reflex or transmission line scheme (to earn some Hz in the low-end side of the spectrum).
How to tune the chamber volume and vent dimensions without knowing the acoustic properties of the drivers?
I know that all of this sounds like a joke, but what I have found in all forums, DIY projects and googling around, it was about "Use some money, buy drivers of known acoustic properties, build the best box according to them". My point of view is different: "give new life to derelict stuff, without spending more than tens of bucks (or even less), possibly making the resulting thing sound well".
Let this serious joke be called "Derelict", after Zoolander's fashion show (the system will be tested using Relax, of course!
)
This is the game, who wants to play?
I'm going to give you available data from the drivers asap.
Ty,
Giorgio
I hope that someone could help me in setting up this project.
First of all, some history...
in the '90 i got a boombox with detachable speakers (guess it was a Grundig) which served me as a music source in the car and going around.
Despite the poor materials, the sound was nice (not HF, of course!
After some years, the whole electronics were stroke by a thunder while wired to the electrical circuit of my house, surprisingly, the plastic closed-cabinet, 2-way speakers seemed be alive and to work well, still.
I trashed all
More recently I bought a cheap commercial t-amp to drive a couple of loudspeakers for the computer. The system sounds fine, but the loudspeakers now in use are definitely too big for my desktop. It is time to make a new "dress" for the old boombox drivers!
So, this is the end of the history and the beginning of the thread:
How to build a decently sounding mini-cabinet for a couple of 2-way drivers, of which I do not know any data at all except dimensions, nominal power and impedance? The whole thing using some MDF or plywood panels at my disposal, elementary tools (jigsaw, soldering stuff and little more) and very very little money?
Closed cabinet is for sure the easiest box to build (I more or less remember dimensions of original plastic boxes), but I'd rather prefer a bass-reflex or transmission line scheme (to earn some Hz in the low-end side of the spectrum).
How to tune the chamber volume and vent dimensions without knowing the acoustic properties of the drivers?
I know that all of this sounds like a joke, but what I have found in all forums, DIY projects and googling around, it was about "Use some money, buy drivers of known acoustic properties, build the best box according to them". My point of view is different: "give new life to derelict stuff, without spending more than tens of bucks (or even less), possibly making the resulting thing sound well".
Let this serious joke be called "Derelict", after Zoolander's fashion show (the system will be tested using Relax, of course!
This is the game, who wants to play?
I'm going to give you available data from the drivers asap.
Ty,
Giorgio
Hi Giorgio... first i can't see any of the pics you have posted but with almost zero money and assuming the drivers use only a cap on the treble for filtering i would build a simplified transmission line using a wood box of approx the same size but with greater depth and a slot rear port. To be honest replacing plastic with wood alone would bring improvements. To see the type of design i 'm talking about google Scythe kro craft rev b speakers for some ideas.
Thank you Konzentr8,
actually, missing images were smilies... I don't know why they were not included in the post, but it's not a problem.
The speakers you suggested seems really elegant, at home I'll try to see if I can obtain something like them from the stuff I already got.
Do you know something about the suggested dimensions of the box and TL?
TY again!
G.
actually, missing images were smilies... I don't know why they were not included in the post, but it's not a problem.
The speakers you suggested seems really elegant, at home I'll try to see if I can obtain something like them from the stuff I already got.
Do you know something about the suggested dimensions of the box and TL?
TY again!
G.
Sorry i can't help with box dimensions but there's a wealth of knowledge on this site and plenty of people happy to advise so i'm sure someone will help . Try a site search and look for something like " Calculating speaker cabinet dimensions " etc . Good luck.
Another option might be to build boxes the size (internal dimensions) of the old ones, if available. Like Konzentr8 mentioned, putting them in a wooden box will be an improvement. If you added a few handfuls of polyfil for stuffing, you might bring it up another notch or two as well.
If the woofers approximately 3 inch drivers, you could look at the TABAQ or the Cyburgs Needle.
http://coolcat.dk/bjoern/TABAQ_TL_for_TB.pdf
https://www.loudspeakerbuilding.com...013/February-2013/_Needle_8563,en,900993,4977
Mike
If the woofers approximately 3 inch drivers, you could look at the TABAQ or the Cyburgs Needle.
http://coolcat.dk/bjoern/TABAQ_TL_for_TB.pdf
https://www.loudspeakerbuilding.com...013/February-2013/_Needle_8563,en,900993,4977
Mike
Why ? generally automobiles are conditioned by internal size, and using low Q speakers that benefit from *not stricly necessary defined cabinet size* is the norm. The size of a plastic box is conditioned by design and usability.
Again, why ? Are you talking about the ability of a material to stop the sound wave ? I avoid plastic because of the petrol smell...
Wood is nicer 🙂 my suggestion for a simplified TL was based on the assumption that cheap boombox drivers aren't " tuned " to the cabinet as you say so making a box ( from wood 🙂 ) with a similar internal design as the Scythes i mentioned wood ( sic ) probably sound ok and could be fine tuned with filling from an old pillow / duvet . Remember the OP has limited funds and trying to make use of what he has available .
Sorry guys for the delay in answering.... Busy days...
I could not take pictures of the drivers, I promise I'll take them during the weekend.
Mikejennens, picowallspeaker: a wood cabinet would be better for sure, since I clearly remember that plastic cabinet was very thin and could deform under load. Moreover, I clearly remember that there was some kind of resonance in plastic cabinet making it awfully vibrate at relatively high volumes.
Finally, wood is more sexy than plastic and better meets my wife aesthetics 😉
About box dimensions, I could try to build different size cabinets and see which one sounds better.
I would like to know, if you can help, something about the "tolerances" of cabinet sizes (or self-oscillating frequencies). How much does the sound change, and how rapidly, when I get close to/far from optimal size? A 20% volume error would give me a good tuning as well, or would it sound terrible?
Finally, is it advisable to have fixed ratios between H/L/W or is it just the total volume to be important? Mind that they would be pc-desktop speakers, thus the nice and elegant speakers suggested by Mikejennens would not apply (but I could try to build them for the tv room 😉 )
Anyway: Konzentr8, I have funds for new drivers, the topic is more a philosophical issue: the re-use of old stuff with minimum extra stuff.
And, of course, some good experimental activity and audio-bricolage fever....
TY all
G.
I could not take pictures of the drivers, I promise I'll take them during the weekend.
Mikejennens, picowallspeaker: a wood cabinet would be better for sure, since I clearly remember that plastic cabinet was very thin and could deform under load. Moreover, I clearly remember that there was some kind of resonance in plastic cabinet making it awfully vibrate at relatively high volumes.
Finally, wood is more sexy than plastic and better meets my wife aesthetics 😉
About box dimensions, I could try to build different size cabinets and see which one sounds better.
I would like to know, if you can help, something about the "tolerances" of cabinet sizes (or self-oscillating frequencies). How much does the sound change, and how rapidly, when I get close to/far from optimal size? A 20% volume error would give me a good tuning as well, or would it sound terrible?
Finally, is it advisable to have fixed ratios between H/L/W or is it just the total volume to be important? Mind that they would be pc-desktop speakers, thus the nice and elegant speakers suggested by Mikejennens would not apply (but I could try to build them for the tv room 😉 )
Anyway: Konzentr8, I have funds for new drivers, the topic is more a philosophical issue: the re-use of old stuff with minimum extra stuff.
And, of course, some good experimental activity and audio-bricolage fever....
TY all
G.
Ideally, the golden ratio can apply to a speaker enclosure- .6:1:1.6
However, having to make some guesses for the enclosures, exact ratio shouldn't be much of an issue.
There is a design for a folded TABAQ. It basically cuts the height in half.
Have fun!
Mike
However, having to make some guesses for the enclosures, exact ratio shouldn't be much of an issue.
There is a design for a folded TABAQ. It basically cuts the height in half.
Have fun!
Mike
here we go with pics and description.
The "woofer" is a 10 cm (4") driver, 10W, 4ohm. some codes on the back could help in identifying it. It was scewed on the cabinet.
The tweeter is a 2cm circular, thin metal plate with a wired smaller black plate glued (?) on the back side. the whole ensamble ould be 1/2mm thick. It was glued (heat glue?) to the cabinet.
I was wrong when I said there was a crossover. No (visible) crossover in between.
Here the pictures:
Back view of the woofer, seems to be a gs-foster
Front view of the driver
Wired-side of the woofer
Front side of the tweeter
wired back-side of the tweeter
Any suggestion/comment?
G.
The "woofer" is a 10 cm (4") driver, 10W, 4ohm. some codes on the back could help in identifying it. It was scewed on the cabinet.
The tweeter is a 2cm circular, thin metal plate with a wired smaller black plate glued (?) on the back side. the whole ensamble ould be 1/2mm thick. It was glued (heat glue?) to the cabinet.
I was wrong when I said there was a crossover. No (visible) crossover in between.
Here the pictures:
An externally hosted image should be here but it was not working when we last tested it.
Back view of the woofer, seems to be a gs-foster
An externally hosted image should be here but it was not working when we last tested it.
Front view of the driver
An externally hosted image should be here but it was not working when we last tested it.
Wired-side of the woofer
An externally hosted image should be here but it was not working when we last tested it.
Front side of the tweeter
An externally hosted image should be here but it was not working when we last tested it.
wired back-side of the tweeter
Any suggestion/comment?
G.
Now i 've managed to stop laughing at that " tweeter " 🙂 i have one suggestion ... bin it .
I would imagine those drivers are " full range " and would sound fine on their own.
No x-over makes life easy especially for Tripath amps . As i mentioned initially find a pic of those Scythes that shows the internal design and build some boxes like them , wire the drivers to a pair of terminals and experiment with internal wadding . I wouldn't worry to much about cabinet parameters around H 20 cm W 16 cm D 25 cm as a starting guide if you use the simplified TL
I would imagine those drivers are " full range " and would sound fine on their own.
No x-over makes life easy especially for Tripath amps . As i mentioned initially find a pic of those Scythes that shows the internal design and build some boxes like them , wire the drivers to a pair of terminals and experiment with internal wadding . I wouldn't worry to much about cabinet parameters around H 20 cm W 16 cm D 25 cm as a starting guide if you use the simplified TL
Incidentally , the reason i suggested taking the tweeters out is because that type of design can potentially damage your amp , fine for things like cheap phones,watches etc but hi-fi no.
What amp do you have btw ?
What amp do you have btw ?
Well, the speakers would be coupled with a cheap lepai tripath. At The moment the amp is feeding a couple of 55w Sony boxes, which are too big for the desk.
Main (living room) setup is based on a couple of '80 active monitors from Grundig which sound decently.
I Will follow your suggestions, drop the "tweeters" and try the shyte design, since the design is really elegant.
Will keep u informed as the project developes.
Main (living room) setup is based on a couple of '80 active monitors from Grundig which sound decently.
I Will follow your suggestions, drop the "tweeters" and try the shyte design, since the design is really elegant.
Will keep u informed as the project developes.
For the money Lapai 's are great little amps . My 2 year old 2024 version has been used to drive all manner of speakers and never let me down. Although now relegated to testing other components i buy it was the amp that introduced me to Tripath / Class D and i 've never looked back.
Easy upgrade use a decent 12 v 5 amp psu not the rubbish it comes with and bypass the tone controls, relevant to both the 2020 and 2024 models.
Not sure if your spelling of scythe was intended but it made me 🙂 I actually own a pair of the upgraded rev B's and for the money they rock . Good luck with the build.
Easy upgrade use a decent 12 v 5 amp psu not the rubbish it comes with and bypass the tone controls, relevant to both the 2020 and 2024 models.
Not sure if your spelling of scythe was intended but it made me 🙂 I actually own a pair of the upgraded rev B's and for the money they rock . Good luck with the build.
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I suggest looking at the Arpeggio speaker article for some inspiration.
http://www.diyaudio.com/forums/diyaudio-com-articles/158899-arpeggio-loudspeaker.html
Maybe not all applicable as you are probably not concerned about a rising inductance but simple tricks like where you position the driver on the baffle can make a real difference.
http://www.diyaudio.com/forums/diyaudio-com-articles/158899-arpeggio-loudspeaker.html
Maybe not all applicable as you are probably not concerned about a rising inductance but simple tricks like where you position the driver on the baffle can make a real difference.
Just had a read of that article , excellent , thanks neighbour 🙂
OP how's the build coming along ?
OP how's the build coming along ?
Hi all,
Sorry for the delay in answering. The building had a stop, since my newborn baby arrived among us in early Jan and all my energy is devoted to her.
Anyway, since my wife is taking a little holiday with my baby-daughter, I guess that I'll try to finalize the project. Stay tuned...
G.
Sorry for the delay in answering. The building had a stop, since my newborn baby arrived among us in early Jan and all my energy is devoted to her.
Anyway, since my wife is taking a little holiday with my baby-daughter, I guess that I'll try to finalize the project. Stay tuned...
G.
My RCA "3-way" 6-ohm boombox speakers had a ~6" woofer cone w/ ported enclosure, a 1.5" mid/tweet cone, and .75" black plastic dome tweeter. Well one day I pried off the grill and unscrewed the speakers and peeked inside. The enclosure contained the woofer direct connected with no crossover whatsoever, and a 4.7uF radial cap inline with the mid/tweet. Surprisingly, the .75" dome tweet wasn't even functional, just decoration. Boy did I feel duped... It consisted of a piece of round plastic glued onto a metal slug glued into an indent in the enclosure. Also the smallish mid/tweet driver was exposed to the enclosure through the back, allowing back sound pressure from the woofer to distort the treble output.
That said, it was the best sounding stereo equipment I owned when I bought it new in 2002, but by no means HiFi. I still use the center component for the tape deck, CD changer, auxillary port, and FM radio, hooked up to a pair of Jensen JP500s ($20 pawn shop find) with flat EQ, and it sounds phenomenal. The Jensens have a horned tweeter and rugged carpet construction with reinforced corners, and have just the right bass rolloff for my room size. I think they were meant for practice gigs like in a garage or stuff, but they're a perfect match to my turntable.
Upgrading the speakers was the best thing that ever happened to that RCA stereo. Why do I bring this up? Your cheapo boombox used a dummy cap instead of a proper crossover, to hopefully match the natural rolloff of the woofer due to it's damping and voice coil inductance. So, like with my RCA stereo, they cheaped out on construction of the speaker, cutting corners everywhere.
What makes you think the old guetto-cap crossed drivers are going to yield outstanding performance in a lovingly crafted enclosure? If they cheaped out on speaker design 101, they probably cheaped out on the drivers as well. Shop around at your local Pawn shops and thrift stores and you might find a decent pair of Pro or HiFi speakers for cheaper than what you'll spend building a new home for your old drivers.
I get these may be sentimental, but time to move on. If you're hell bent on keeping them, then upcycle an old lunch box or something. You may be surprised. I recently built my first boombox briefcase out of a $5 thrift shop find (brown American Traveler Tiara) and a pair of 5.5" full range drivers (with whizzer cones) I scavanged a couple years back from a discarded rear projection HDTV. I paired it with a Kinter amp (FM tuner and MP3 media slot included) mounted on the back, andwith the undamped masonite hardcase, it's got this "retro" sound just like a 60s console radio. Goes plenty loud and nice warm tones with the bass knob at 4 o'clock and treble at 2 o'clock.
4" drivers might be a bit small for a briefcase and too big for a lunchbox, but consider upcycling an old piece of junk by converting it into an enclosure.
That said, it was the best sounding stereo equipment I owned when I bought it new in 2002, but by no means HiFi. I still use the center component for the tape deck, CD changer, auxillary port, and FM radio, hooked up to a pair of Jensen JP500s ($20 pawn shop find) with flat EQ, and it sounds phenomenal. The Jensens have a horned tweeter and rugged carpet construction with reinforced corners, and have just the right bass rolloff for my room size. I think they were meant for practice gigs like in a garage or stuff, but they're a perfect match to my turntable.
Upgrading the speakers was the best thing that ever happened to that RCA stereo. Why do I bring this up? Your cheapo boombox used a dummy cap instead of a proper crossover, to hopefully match the natural rolloff of the woofer due to it's damping and voice coil inductance. So, like with my RCA stereo, they cheaped out on construction of the speaker, cutting corners everywhere.
What makes you think the old guetto-cap crossed drivers are going to yield outstanding performance in a lovingly crafted enclosure? If they cheaped out on speaker design 101, they probably cheaped out on the drivers as well. Shop around at your local Pawn shops and thrift stores and you might find a decent pair of Pro or HiFi speakers for cheaper than what you'll spend building a new home for your old drivers.
I get these may be sentimental, but time to move on. If you're hell bent on keeping them, then upcycle an old lunch box or something. You may be surprised. I recently built my first boombox briefcase out of a $5 thrift shop find (brown American Traveler Tiara) and a pair of 5.5" full range drivers (with whizzer cones) I scavanged a couple years back from a discarded rear projection HDTV. I paired it with a Kinter amp (FM tuner and MP3 media slot included) mounted on the back, andwith the undamped masonite hardcase, it's got this "retro" sound just like a 60s console radio. Goes plenty loud and nice warm tones with the bass knob at 4 o'clock and treble at 2 o'clock.
4" drivers might be a bit small for a briefcase and too big for a lunchbox, but consider upcycling an old piece of junk by converting it into an enclosure.
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Stardust,
thank you for sharing your experience and comments.
As you suggested, it has become now a matter of sentimentalism and holding the point, BUT it is also in some respects a sort of experiment on how the sound can get better with better, although cheap, enclosure (and despite the complete dumbness of the author...)
Cheers
G.
thank you for sharing your experience and comments.
As you suggested, it has become now a matter of sentimentalism and holding the point, BUT it is also in some respects a sort of experiment on how the sound can get better with better, although cheap, enclosure (and despite the complete dumbness of the author...)
Cheers
G.
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