Hi!
Last year around christmas I went to a skiing trip, and there was a gyu with me who carried a comparatively big "Ghetto Blaster", I think made by Aiwa with him. It had two bass drivers, was made out of the thickest plastic I have ever seen or felt on such a thing, and could produce an enormous amount of bass (and at high levels, too). Of course there must've been some equlaising at work, but it sounded very nice for such a product.
Now I am wondering, if I could build something better for myself. Not with a radio or CD included, simply a long case with the pre/amplifiers, connectors and loudspeakers, made out of MDF.
While I'm pretty sure about what amplifier technology to use (either GC for mid/high and GC with current afterburner for bass, or GC for mid/high and P3A for bass), and an old Thomessen Bass Expander processor, I am not so sure about the speaker chassis.
I was thinking about using a ready-made 3-way speaker cit for cars, because they seem to offer best value-for-money, for example Canton CS 3.22.
Of course I could also use home chassis, but then I don't have any equipment for measuring & building good passive XOs at home, and therefore would like to avoid running into troubles because of badly constructed XOs...
Any ideas, advices?
Bye,
Arndt
Last year around christmas I went to a skiing trip, and there was a gyu with me who carried a comparatively big "Ghetto Blaster", I think made by Aiwa with him. It had two bass drivers, was made out of the thickest plastic I have ever seen or felt on such a thing, and could produce an enormous amount of bass (and at high levels, too). Of course there must've been some equlaising at work, but it sounded very nice for such a product.
Now I am wondering, if I could build something better for myself. Not with a radio or CD included, simply a long case with the pre/amplifiers, connectors and loudspeakers, made out of MDF.
While I'm pretty sure about what amplifier technology to use (either GC for mid/high and GC with current afterburner for bass, or GC for mid/high and P3A for bass), and an old Thomessen Bass Expander processor, I am not so sure about the speaker chassis.
I was thinking about using a ready-made 3-way speaker cit for cars, because they seem to offer best value-for-money, for example Canton CS 3.22.
Of course I could also use home chassis, but then I don't have any equipment for measuring & building good passive XOs at home, and therefore would like to avoid running into troubles because of badly constructed XOs...
Any ideas, advices?
Bye,
Arndt
I would be careful with car hifi speakers.
They are usually made for, let's say, "uncertain" mounting conditions (car doors etc.). With an MDF case, you can use a true sealed, vented, or bandpass design. So I think it would be a good idea to go for serious hifi or even PA drivers with reliable parameters available.
The central question is: how much bass do you want? What is the desired -3db point?
They are usually made for, let's say, "uncertain" mounting conditions (car doors etc.). With an MDF case, you can use a true sealed, vented, or bandpass design. So I think it would be a good idea to go for serious hifi or even PA drivers with reliable parameters available.
The central question is: how much bass do you want? What is the desired -3db point?
Hi!
The XO should be half-active (active for sub to mid, passive for mid/high), and the XO frequency I want to find out with listening tests, and in accordance to the size of the midrange driver, shouldn't be above 80 Hz.
I even would substitute an absolute maximum of volume level for deeper bass, as deep as it can possibly go with a "standard" ghetto blaster volume of say about 30 - 40 l, and with active equlisation.
One possiblility would also be:
Use home hifi equipment (or PA) for the sub part, and a coax car hifi chassis for mid/high range, saves space...
I think that a closed volume would allow me a smaller enclosure size (remember the EQ), which is ultimately the way to go for me...
Bye,
Arndt
The XO should be half-active (active for sub to mid, passive for mid/high), and the XO frequency I want to find out with listening tests, and in accordance to the size of the midrange driver, shouldn't be above 80 Hz.
I even would substitute an absolute maximum of volume level for deeper bass, as deep as it can possibly go with a "standard" ghetto blaster volume of say about 30 - 40 l, and with active equlisation.
One possiblility would also be:
Use home hifi equipment (or PA) for the sub part, and a coax car hifi chassis for mid/high range, saves space...
I think that a closed volume would allow me a smaller enclosure size (remember the EQ), which is ultimately the way to go for me...
Bye,
Arndt
On a small two-way speaker using Dynaudio drivers (not at all known to be very efficient !!) I didn't glue in the port tubes. They just fit snug and can be easily removed.
As a demo I sometimes used to remove the tubes to get a boomy misalignment (I guess ahump of about 6 dB). The resulting mid-to upper bass was quite loud (you should have seen the faces !!). I think you could do something like that (boom-box alignment) together with a "sub"-sonic filter.
The quality of bass wouldn't be very high but there would be quite some quantity of boomy bass. I think that is what most people expect from a ghetto blaster.
You could of course as well build a high-quality Ghetto Blaster but the efforts would be much larger (and be more stunning of course).
Regards
Charles
As a demo I sometimes used to remove the tubes to get a boomy misalignment (I guess ahump of about 6 dB). The resulting mid-to upper bass was quite loud (you should have seen the faces !!). I think you could do something like that (boom-box alignment) together with a "sub"-sonic filter.
The quality of bass wouldn't be very high but there would be quite some quantity of boomy bass. I think that is what most people expect from a ghetto blaster.
You could of course as well build a high-quality Ghetto Blaster but the efforts would be much larger (and be more stunning of course).
Regards
Charles
Cool project
I've been threatening to do the same thing myself for quite some time. Costs, aside my vision included a CD player (maybe the Daisy kit) and a tuner. I thought it might be fun do do a folded or coiled TL and put some of the less sensitive parts inside the TL. Since I know little of TL's yet, I'm not sure how it would effect the performance, but it's food for thought. The other thing I thought could work well was NiCad or NiMh battery power supply and built in quick charger, this would cost a little more than a really good PS, but you get the advantages of the "ideal" battery PS and portability.
I think the GB is a highly overlooked part of DIY, maybe we could start a trend.
Chris
I've been threatening to do the same thing myself for quite some time. Costs, aside my vision included a CD player (maybe the Daisy kit) and a tuner. I thought it might be fun do do a folded or coiled TL and put some of the less sensitive parts inside the TL. Since I know little of TL's yet, I'm not sure how it would effect the performance, but it's food for thought. The other thing I thought could work well was NiCad or NiMh battery power supply and built in quick charger, this would cost a little more than a really good PS, but you get the advantages of the "ideal" battery PS and portability.
I think the GB is a highly overlooked part of DIY, maybe we could start a trend.
Chris
I've built once a portable. I used Panasonic minicomponents and Blaupunkt amp. The case is out of 1/2" MDF and drivers are Seas or Audax IIRC. Although a bit heavy it was better than any commercial units available at the time. This was also before GC madness😉
I was also contemplating building another unit with better components and chassis made of honey comb material used for aircraft floor panels. I have a nice Alpine deck, Pioneer CD player which would fit nicely here and the amp would use GC technology.
I was also contemplating building another unit with better components and chassis made of honey comb material used for aircraft floor panels. I have a nice Alpine deck, Pioneer CD player which would fit nicely here and the amp would use GC technology.
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Let me be just a little bit of a ***** here and give my usual advice:
DIPOLE!!! Seriously, a couple of 5"-7" high xmax drivers in a push-pull configuration, with a couple of small, cheap soft-dome tweeters... you would be able to play for an audience of 100 by just setting the thing down in the middle of the room! It would be larger than the average boombox, but you could use electronic falloff compensation instead of the usual method of a high-Q driver with a resonant frequency beneath the -3 point... This would give nice, tight bass in a small space, and when you're pushing those high xmax 6" drivers to their limits, it really is a substantial amount of bass.
Dang. Now I want to build one too. And I have no money to do so! Waah!
DIPOLE!!! Seriously, a couple of 5"-7" high xmax drivers in a push-pull configuration, with a couple of small, cheap soft-dome tweeters... you would be able to play for an audience of 100 by just setting the thing down in the middle of the room! It would be larger than the average boombox, but you could use electronic falloff compensation instead of the usual method of a high-Q driver with a resonant frequency beneath the -3 point... This would give nice, tight bass in a small space, and when you're pushing those high xmax 6" drivers to their limits, it really is a substantial amount of bass.
Dang. Now I want to build one too. And I have no money to do so! Waah!
If you want to do it the easy way, buy a Bose Wave Radio and a Radio Shack portable CD player and duct tape them together. You'll notice that people will avoid eye contact and leave you strictly alone.
It does help to actually wet your pants while you're walking around. Prevents muggings.
It does help to actually wet your pants while you're walking around. Prevents muggings.
Hi!
Yeah, actually I think it was from JVC, and it was a tube, with the bass drivers looking out of both ends of the tube...
Actually I made a bet with myself that you would show up with something you've already build 😉
Although I have a spare Onkyo amp lying around, it is the normal big size, so wouldn't suit my project well...
But...
I could rip out the amp part...
And then use my spare End Millenium module for bass...
But actually that would be a little be over the top...
But thanks for input so far...
Bye,
Arndt
ksl said:
Yeah, actually I think it was from JVC, and it was a tube, with the bass drivers looking out of both ends of the tube...
Peter Daniel said:
Actually I made a bet with myself that you would show up with something you've already build 😉
Although I have a spare Onkyo amp lying around, it is the normal big size, so wouldn't suit my project well...
But...
I could rip out the amp part...
And then use my spare End Millenium module for bass...
But actually that would be a little be over the top...
But thanks for input so far...
Bye,
Arndt
You call that a challenge?
Hey, let's make it really difficult. Let's say that the GB should be capable of using a battery supply - 16 or 24 D-cells like the biggest commercial ones. I'd say that would call for a class d solution.
Hey, let's make it really difficult. Let's say that the GB should be capable of using a battery supply - 16 or 24 D-cells like the biggest commercial ones. I'd say that would call for a class d solution.
MDF is about the worst thing to use- It is really heavy and damages easily. I would suggest well braced plywood. The PVC idea is brilliant, but large diameters of PVC are expensive and also generally only available in 10' lengths.
I vote for about an 8" diameter piece of PVC with a PVC cap on each end and a fullrange Fostex 6 or 8" speaker or a Jordan. with a GC inside. The fostex's are more efficient. Maybe it should just have one speaker and a second pipe with amp for the second speaker so you could just use it in mono if you need something more compact. Of course use a walkman type portable CD player and just plug it in!
I vote for about an 8" diameter piece of PVC with a PVC cap on each end and a fullrange Fostex 6 or 8" speaker or a Jordan. with a GC inside. The fostex's are more efficient. Maybe it should just have one speaker and a second pipe with amp for the second speaker so you could just use it in mono if you need something more compact. Of course use a walkman type portable CD player and just plug it in!
My PA system is built of various grades of plywood, from the nicest stuff that I still feel blasphemous for spraypainting black, to CDX board, that I really should've gone with a thicker material.
The PA system is all sexy though, because it's apholstered with nagahide (think artificial leather--it's very tough stuff) and it's stuffed with quilt batting.
I think this should be the outside of the boombox--artificial leather. With gold chains and purple / leopard fur. Or not.
In any case, I like the idea of this alot. I'm going to keep watching and probably build something eventually...
Hey, what about a full-range speaker and a 37th-order bandpass box for bass? 😀 Then the woofer drivers wouldn't have to be exposed to the weather or anything. Hehe, no, I guess that would be too much.
The PA system is all sexy though, because it's apholstered with nagahide (think artificial leather--it's very tough stuff) and it's stuffed with quilt batting.
I think this should be the outside of the boombox--artificial leather. With gold chains and purple / leopard fur. Or not.
In any case, I like the idea of this alot. I'm going to keep watching and probably build something eventually...
Hey, what about a full-range speaker and a 37th-order bandpass box for bass? 😀 Then the woofer drivers wouldn't have to be exposed to the weather or anything. Hehe, no, I guess that would be too much.
TuckN'Roll
When the JBL Copntrol-1 came out (long time ago) I mused with the idea of a portable radio using a car cassette deck, the JBL's and a couple of motorcycle batteries.
I like the padded cabinet idea from NappyLady. Sounds a lot like the Kustom Sound TuckN'Roll cabinets.
When the JBL Copntrol-1 came out (long time ago) I mused with the idea of a portable radio using a car cassette deck, the JBL's and a couple of motorcycle batteries.
I like the padded cabinet idea from NappyLady. Sounds a lot like the Kustom Sound TuckN'Roll cabinets.
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I used a Creative PC Works system (supremely cheap), 2 x 6V lantern batteries and made this audible Halloween costume last year. Just this weekend, it got used to provide dramatic musical accompaniment to a frisbee throwing machine and was powered by a 12V NiMH pack from a bike light system.
🙂ensen.
And yes... it's a Jensen Speaker.
🙂ensen.
And yes... it's a Jensen Speaker.
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Hi!
Well, sadly this is just theoretical stuff for me right now, since (as a student) money's always short, and enough DIY audio stuff is still waiting to be finished right now, and bying a 17" LCD panel for my computer is also top priority (Hyundai Q17...).
But I always like to combine project. Trying out the "current afterburner" version of the GC was always something I wanted to do, and also building a combined amplifier / speaker unit for travels (not what you think of as travels, I work as a cook in Ski resorts during Winter, and beach resorts during Summer, and absolutely hate the crappy 30€ blasters the firm I'm working for is providing).
The unit is not intended to be carried around very much, only upon location change during my travels...
Maybe I will just start building the GC (have some spare LM and BB power OPs, some MJ15003/15004, some heatsinks, some toroids... only caps are missing...), and attach an old 4 ohms speaker I built four years ago, in order to try the bass handling capabilities...
Btw, how can I measure the output voltage of an audio source? simply attach multimeter in AC/DC configuration, and apply sinus wave? I would like to check all my carry-around-stuff like discmen, MP3 players... for their output level, in order to check if I need a pre-amp or not...? 😕
Bye,
Arndt
Nappylady said:
Well, sadly this is just theoretical stuff for me right now, since (as a student) money's always short, and enough DIY audio stuff is still waiting to be finished right now, and bying a 17" LCD panel for my computer is also top priority (Hyundai Q17...).
But I always like to combine project. Trying out the "current afterburner" version of the GC was always something I wanted to do, and also building a combined amplifier / speaker unit for travels (not what you think of as travels, I work as a cook in Ski resorts during Winter, and beach resorts during Summer, and absolutely hate the crappy 30€ blasters the firm I'm working for is providing).
The unit is not intended to be carried around very much, only upon location change during my travels...
Maybe I will just start building the GC (have some spare LM and BB power OPs, some MJ15003/15004, some heatsinks, some toroids... only caps are missing...), and attach an old 4 ohms speaker I built four years ago, in order to try the bass handling capabilities...
Btw, how can I measure the output voltage of an audio source? simply attach multimeter in AC/DC configuration, and apply sinus wave? I would like to check all my carry-around-stuff like discmen, MP3 players... for their output level, in order to check if I need a pre-amp or not...? 😕
Bye,
Arndt
reply
I Remember the JVC boom blaster with it's camo style [rubber end caps and camoflauge pvc body.]A 6 inch sub in each end[with funny ports sticking out] and x2 4 inch fullranges at the front.
I used to own a boomblaster but even though it had two 6 inches[most 6 inches cannot handle sub bass frequencies].Which the boomblaster circuitry was producing and making the low wattage 20w rms subs 'bottom out' hit the back plate.
Who even back then I replaced the crappy JVC bass drivers with some Beyma pro pa drivers[same ohms of course],and replaceable the crappy 5 w rms fullrange speakers in the centre with 2 way coaxial speakers[same ohms of course].
Then after the modifcation it handled the bass a lot better and went much louder and clearer and it was the first portable system which has loud enough for disco use[at the time when i was rather poor and young [15]].
I Remember the JVC boom blaster with it's camo style [rubber end caps and camoflauge pvc body.]A 6 inch sub in each end[with funny ports sticking out] and x2 4 inch fullranges at the front.
I used to own a boomblaster but even though it had two 6 inches[most 6 inches cannot handle sub bass frequencies].Which the boomblaster circuitry was producing and making the low wattage 20w rms subs 'bottom out' hit the back plate.
Who even back then I replaced the crappy JVC bass drivers with some Beyma pro pa drivers[same ohms of course],and replaceable the crappy 5 w rms fullrange speakers in the centre with 2 way coaxial speakers[same ohms of course].
Then after the modifcation it handled the bass a lot better and went much louder and clearer and it was the first portable system which has loud enough for disco use[at the time when i was rather poor and young [15]].
reply
Yep i've seen those old type before.
Big main speakers on that one can't tell from the pic but i'd say between 4 inch-8 inch.
Anyway the rest of the unit is crap,no Compact Disc,and no LCD display radio.Giant buttons and dials.
Also remember a weird ghettoblaster by Panasonic with two normal crappy fullrange speakers and a weird thing called 'an acoustic seperator' right deep inside the ghetto blaster.
Took one of these weird ghetto blasters apart once and the fancy name 'acoustic seperator' is just a bandpass mini sub with a 5 1/4 inch driver rated 30w rms and low pass filter in a White ABS plastic enclousure,which fitted inside the main body of the ghetto blaster.
But the strange thing about this 'acoustic seperator cabinet' was it had a plastic horn path with many bends like a transmission line,but you couldn't see the driver inside,and it had two port opening either side like a bandpass box.So it gave the listener the impression a 10 inch woofer was being used when really it was just a 5 1/4 inch woofer.
Yep i've seen those old type before.
Big main speakers on that one can't tell from the pic but i'd say between 4 inch-8 inch.
Anyway the rest of the unit is crap,no Compact Disc,and no LCD display radio.Giant buttons and dials.
Also remember a weird ghettoblaster by Panasonic with two normal crappy fullrange speakers and a weird thing called 'an acoustic seperator' right deep inside the ghetto blaster.
Took one of these weird ghetto blasters apart once and the fancy name 'acoustic seperator' is just a bandpass mini sub with a 5 1/4 inch driver rated 30w rms and low pass filter in a White ABS plastic enclousure,which fitted inside the main body of the ghetto blaster.
But the strange thing about this 'acoustic seperator cabinet' was it had a plastic horn path with many bends like a transmission line,but you couldn't see the driver inside,and it had two port opening either side like a bandpass box.So it gave the listener the impression a 10 inch woofer was being used when really it was just a 5 1/4 inch woofer.
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