Maybe I'm crazy, I was about to buy a vintage Ghetto Blaster off of Ebay, yes the big heavy ones (some up to 20 lbs) because I want a good sounding portable radio for the pool in my apmartment complex, going to the park etc ...
Instead I decided to try to build my own, and I didn't want to go the car audio headunit approach which would necessitate a car or motorcycle battery b/c it would be way too heavy. I decided to try this using the SI T Amp which runs off of i think 8 AA batteries.
What i am planning on doing, and please offer advice, is building a mold of the unit out of light balsa wood, then putting fiberglass cloth and epoxy on both sides for strengh, I would think that would be much stronger than the plastic that ghetto blasters were made out of anyway. From all of my reading on t amps, they prefer driving a single high efficiency speaker rather than using a cross over etc ...
I was thinking about using full range speakers anywhere in the 5-10" range ... I would like this thing to have a very full sound, and If I have to bi-amp the thing, running 2 t amps .. that's ok too ... So if you could point me in the right direction in terms of speaker selection, and the type of enclosures (sealed, vented, etc) that would be great!
Thanks in advance!
Instead I decided to try to build my own, and I didn't want to go the car audio headunit approach which would necessitate a car or motorcycle battery b/c it would be way too heavy. I decided to try this using the SI T Amp which runs off of i think 8 AA batteries.
What i am planning on doing, and please offer advice, is building a mold of the unit out of light balsa wood, then putting fiberglass cloth and epoxy on both sides for strengh, I would think that would be much stronger than the plastic that ghetto blasters were made out of anyway. From all of my reading on t amps, they prefer driving a single high efficiency speaker rather than using a cross over etc ...
I was thinking about using full range speakers anywhere in the 5-10" range ... I would like this thing to have a very full sound, and If I have to bi-amp the thing, running 2 t amps .. that's ok too ... So if you could point me in the right direction in terms of speaker selection, and the type of enclosures (sealed, vented, etc) that would be great!
Thanks in advance!
Interesting project. I'm listening to my Tamp through a set of Advent L. at the moment. So no worry about the Tamp driving a couple of fullrange drivers.I would definitely go with a sealed box as the application kind of warrants it, IMO. If Ebay isn't your way then a pick from Madisound like this might work:http://www.madisound.com/cgi-bin/index.cgi?cart_id=3177900.26597&pid=100 or a larger woofer with a coaxial tweeter. Possibilities are really endless. Good luck with this and keep us posted.
This is an interesting project. I know that I typically carry around a t-amp, some small speakers (old Panasonics), an ipod and a cigarette lighter power cable in my car. Sometimes I use the rig in a high school classroom (I'm a teacher) hooked up to a computer. I'd love to have something with a handle on it that easily carries the speakers for both sides.
I'm surprised you haven't had better response on this forum yet, but you haven't specified your price limits and weight & size limits for the enclosures. Once you do, you'll be sure to tweak the curiosity of those who are more knowledgable about drivers than I.
Most say that the t-amps are a natural match to Fostex drivers. But my impression is that many of the Fostex drivers are fairly fragile, and might not stand up under the abuse that portable speakers get. Also, for ultimate sound quality, the drivers normally need quite large enclosures.
Randy
I'm surprised you haven't had better response on this forum yet, but you haven't specified your price limits and weight & size limits for the enclosures. Once you do, you'll be sure to tweak the curiosity of those who are more knowledgable about drivers than I.
Most say that the t-amps are a natural match to Fostex drivers. But my impression is that many of the Fostex drivers are fairly fragile, and might not stand up under the abuse that portable speakers get. Also, for ultimate sound quality, the drivers normally need quite large enclosures.
Randy
Coolest portible system I ever saw was housed in an aluminium flight case. Something like this perhaps: http://www.maplin.co.uk/Module.aspx?ModuleNo=36796&criteria=flight case&doy=10m5
Fascinating project. One idea is to study the technology behind the Bose wave radio. It would be difficult to build, but you might just get away with making something that sounds pretty good with small drivers that are fully protected inside the box.
I see this as a project that definitely needs mockups in cardboard and plastic first. Keep us posted. I would like to know what you figure out.
Doug
I see this as a project that definitely needs mockups in cardboard and plastic first. Keep us posted. I would like to know what you figure out.
Doug
To answer some of you guys questions ...
I don't mind using a ported enclosure. I plan on making this think look like a guitar amp, shaped in the typical horizontal layout of a boombox, with a fabric "slide in" that will cover the entire front of the box which protects the speakers.
I would like Qtc to be as close to 1 as appropriate. I do want bass response, but i want it to be natural. Boom when it should, and only then. I would like it to be a little Hifi wonder, fit for classical, and/or capable of playing the latest from Kayne West
Nothing like listening to a little "Gold Digger" here in dallas ...
I was prepared to use up 10" driver, but now that i think about it, it is obviously not wise, given the enclosure size needed to get a decent Qtc. Plus the weight factor.
The Fostex FE126E 4.5" full range driver recommended by DocLorren, and available from Madisound at around $37, is pretty compelling. The factory spec sheet says the recommended bass refex enclosure would be 265mm or 10.43 high (inside measurements), 150mm or 5.9" wide, and 265mm or 265mm or 10.4" deep. Internal Volume is 10.5 litres, and the port tube is tuned to 61hz. All of which would be very "do-able."
The budget, can't say, for sure less than $300, would rather it be less than $200 but we'll see. Weight budget? trying to keep it less than 20 pounds -- The fostex FE126E's are 2.22 lbs each. Given that the T Amp is around 1 pound, and batteries likely to be another, I should be well under the weight requirement If i used those.
Source? I was planning on using my ipod. They sell interesting little IPOD docking stations with line outs that have a simple IR controller that you can use to change tracks, and increase or decrease volume ... perhaps I could use that as my volume device. You can find these on ebay for around $20. Otherwise a simple steel volume nob on the top front of the unit could work.
I did a quick check on the bose acoustic wave, and the type of lLabyrinth enclosures look pretty complicated, and from what people tell me they don't have a flat freq response. The base is boomey, but missing large chunks of the spectrum.
I don't know guys, but it seems for less than $200 we should be able to design a pretty awsome sounding hifi boombox. Even if you modded the T Amp with better capacitors and perhaps a heat sink, or even bi-amped it if we found the output to be too low, we would still be underbudget and underweight. The sensativity of those 4.5" fostex drives are impressive at 93 db/W.
What do you guys think? Open to any ideas .. and for others to build along
I don't mind using a ported enclosure. I plan on making this think look like a guitar amp, shaped in the typical horizontal layout of a boombox, with a fabric "slide in" that will cover the entire front of the box which protects the speakers.
I would like Qtc to be as close to 1 as appropriate. I do want bass response, but i want it to be natural. Boom when it should, and only then. I would like it to be a little Hifi wonder, fit for classical, and/or capable of playing the latest from Kayne West
Nothing like listening to a little "Gold Digger" here in dallas ...I was prepared to use up 10" driver, but now that i think about it, it is obviously not wise, given the enclosure size needed to get a decent Qtc. Plus the weight factor.
The Fostex FE126E 4.5" full range driver recommended by DocLorren, and available from Madisound at around $37, is pretty compelling. The factory spec sheet says the recommended bass refex enclosure would be 265mm or 10.43 high (inside measurements), 150mm or 5.9" wide, and 265mm or 265mm or 10.4" deep. Internal Volume is 10.5 litres, and the port tube is tuned to 61hz. All of which would be very "do-able."
The budget, can't say, for sure less than $300, would rather it be less than $200 but we'll see. Weight budget? trying to keep it less than 20 pounds -- The fostex FE126E's are 2.22 lbs each. Given that the T Amp is around 1 pound, and batteries likely to be another, I should be well under the weight requirement If i used those.
Source? I was planning on using my ipod. They sell interesting little IPOD docking stations with line outs that have a simple IR controller that you can use to change tracks, and increase or decrease volume ... perhaps I could use that as my volume device. You can find these on ebay for around $20. Otherwise a simple steel volume nob on the top front of the unit could work.
I did a quick check on the bose acoustic wave, and the type of lLabyrinth enclosures look pretty complicated, and from what people tell me they don't have a flat freq response. The base is boomey, but missing large chunks of the spectrum.
I don't know guys, but it seems for less than $200 we should be able to design a pretty awsome sounding hifi boombox. Even if you modded the T Amp with better capacitors and perhaps a heat sink, or even bi-amped it if we found the output to be too low, we would still be underbudget and underweight. The sensativity of those 4.5" fostex drives are impressive at 93 db/W.
What do you guys think? Open to any ideas .. and for others to build along
dellaseppes said:
A nice feature to consider: making the speakers detachable. Maybe you could put a more solid grill over them to protect the paper cone drivers.
Although I have not heard this driver, it is universally liked by those who have paired it with t-amps.
The weight of this enclosure could become significant, determining whether you bother to lug it around sometimes. You might consider optimizing the dimensions of the boxes for least amount of material (for same internal volume), making them wider, less deep, and shorter. The shape of the front baffle is less relevant anyway, since the center of the box will be on the same plane as the baffle.
Choice of enclosure material is critical here also. MDF weighs more than plywood, which weighs more than hardwood. Are you considering higher tech alternatives? Plastics? Fiberglass?
I assume that BR type enclosures are more subject to resonances than larger boxes. The heavier materials are less subject to resonance. Anyone know what would be the best compromise here?
No doubt the electronically controlled pots are a pretty serious compromise of sound quality. Personally, I wouldn't see enough convenience from the IR control to go that route.
Randy
I have been working out how to solve this exact "problem"...i would like a boombox to take with me to ultimate frisbee tournaments (all day long outdoor affairs played with teams). Lots of people bring music to the field, but they bring it in the form of a walmart cdp boombox...you can't even hear the thing when you're sitting next to it...as if you would want to anyway.
My question on these lines...how big a deal is it to run the speakers on the same front baffle? Would your enclosure have two separate chambers? Maybe the discussion hasn't gotten here yet, or maybe I'm a moron for not knowing the answers. What about a box in which you made two separate front baffles by angling them slightly outwards? That would have the benefit of giving you non-paralell sides, too....
Excited to be reading everyone's ideas on this. My project is not the hifi adventure delaseppes is taking on...I'm doing it the free way using 5-1/4" car speakers that used to be in my girlfriend's car and some leftover MDF...heavy, I know, but free. Not trying to hijack this thread, though...just trying to learn from other's projects.
My question on these lines...how big a deal is it to run the speakers on the same front baffle? Would your enclosure have two separate chambers? Maybe the discussion hasn't gotten here yet, or maybe I'm a moron for not knowing the answers. What about a box in which you made two separate front baffles by angling them slightly outwards? That would have the benefit of giving you non-paralell sides, too....
Excited to be reading everyone's ideas on this. My project is not the hifi adventure delaseppes is taking on...I'm doing it the free way using 5-1/4" car speakers that used to be in my girlfriend's car and some leftover MDF...heavy, I know, but free. Not trying to hijack this thread, though...just trying to learn from other's projects.
I don't think the FE126e are the best application. The driver's Qtc is too low and you won't get enough bass from them. They are best used in a BLH. The application of "Boombox" is the defining factor in the build, IMO. You need drivers that will deliver full-range FR and will be loud enough to play outdoors or in large rooms. The elimination of a crossover and tweeter would simplify the build. Also, I would aim for a cone other than the lightweight paper because of durability. Audio Nirvana selld a 6.5 that is fairly efficient: http://www.nirvanaspeakers.com/nirvana.html . Their micro monitor plan would seem to fit the size requirements. Expensive though, relative to more traditional boombox drivers. It might be advantageous to use cheaper drivers for experimentation and size the enclosure to accrpt an upgrade for the future. My .03.
The Tangband w3-871s provide a stunning preformance in a 1.5 litre BR cabinet (in my opinion).
For a very small speaker cabinet it may be advantageous to design the format to reduce reflection back through the cone.
See post no. 38 and 42 in this thread for a "prototype" with the 871s: http://www.diyaudio.com/forums/showthread.php?s=&threadid=74401&perpage=10&pagenumber=4
For a very small speaker cabinet it may be advantageous to design the format to reduce reflection back through the cone.
See post no. 38 and 42 in this thread for a "prototype" with the 871s: http://www.diyaudio.com/forums/showthread.php?s=&threadid=74401&perpage=10&pagenumber=4
how about only one driver ?
very interesting thread. As this is about lateral thinking, anyone consider the possibility of using a single driver i.e one speaker . I say this cos I have a Tivoli 1 in my kitchen I listen to from FM stereo or via the linein from a walkman. It's a single speaker device and sounds amazing. I could never figure out the benefit of stereo speakers that were 6 " apart on a boombox. Just a thought , but designing for one speaker rather than two might free up some useful enclosure space, rather like in a guitar practice amp as mentioned earlier. Just a thought
very interesting thread. As this is about lateral thinking, anyone consider the possibility of using a single driver i.e one speaker . I say this cos I have a Tivoli 1 in my kitchen I listen to from FM stereo or via the linein from a walkman. It's a single speaker device and sounds amazing. I could never figure out the benefit of stereo speakers that were 6 " apart on a boombox. Just a thought , but designing for one speaker rather than two might free up some useful enclosure space, rather like in a guitar practice amp as mentioned earlier. Just a thought
Earlier I had suggested the idea of having detachable speakers. My idea was that both speakers could be moved away from the central unit.
But, after reading other suggestions, including the idea of both sides sharing internal volume, it occured to me that you could simplify this by making only one speaker detachable. Then you could realize stereo separation when the environment allows, and cut in half the number of complications that come from devising a clipping system.
Randy
But, after reading other suggestions, including the idea of both sides sharing internal volume, it occured to me that you could simplify this by making only one speaker detachable. Then you could realize stereo separation when the environment allows, and cut in half the number of complications that come from devising a clipping system.
Randy
T amp boom box?
Why not seek out a Virgin boom tube.?Although not DIY , it seems like it would fit your needs for not much more than the cost of the components. I did try buying one off the internet (epay), but the seller "oversold" his stock. If ya can find one, I'd try that. I suspect Tangband drivers. And the Tamp, in a nice compact case, slightly larger than a large Thermos.
Why not seek out a Virgin boom tube.?Although not DIY , it seems like it would fit your needs for not much more than the cost of the components. I did try buying one off the internet (epay), but the seller "oversold" his stock. If ya can find one, I'd try that. I suspect Tangband drivers. And the Tamp, in a nice compact case, slightly larger than a large Thermos.
Re: T amp boom box?
Not everyone would be satisfied with paying over $200 for a system with 2" drivers, although the tube idea is interesting. Why not a 4.5" diameter tube with handle and detachable ends giving R,L and sub?
Although more exensive to build than a boom tube, it would be a kickass portable system.
Randy
Nanook said:
Not everyone would be satisfied with paying over $200 for a system with 2" drivers, although the tube idea is interesting. Why not a 4.5" diameter tube with handle and detachable ends giving R,L and sub?
Although more exensive to build than a boom tube, it would be a kickass portable system.
Randy
I've actually thought about this sort of project as well. We have a semi-remote property that we'll be camping at/working on over the summer with no power. Some type of system that's better than a typical boombox would be great.
there are lots of tradeoffs to make between features and weight, but I think a car-stereo approach has some things to recommennd it. There are higher end auto head-units that do active xover functionality on-board and will power (usually) the mid and tweet directly. IMHO makes doing a quick-and-dirty 2.5 way system feasible.
The battery will be heavy, but IMHO you'd really need a decent battery even for the SI if you want something better than the typical boombox.
My plan (since I already have all this stuff) is to use my Alpine 9815 head unit, HiVi B3N's and Dayton neo tweets, and maybe a TB W8-740c 'sub'. Assuming I can find the time to slap it all together, that is.
there are lots of tradeoffs to make between features and weight, but I think a car-stereo approach has some things to recommennd it. There are higher end auto head-units that do active xover functionality on-board and will power (usually) the mid and tweet directly. IMHO makes doing a quick-and-dirty 2.5 way system feasible.
The battery will be heavy, but IMHO you'd really need a decent battery even for the SI if you want something better than the typical boombox.
My plan (since I already have all this stuff) is to use my Alpine 9815 head unit, HiVi B3N's and Dayton neo tweets, and maybe a TB W8-740c 'sub'. Assuming I can find the time to slap it all together, that is.
There are definite parallels to car audio here, because the volume of the enclosures is an important consideration. Car speakers are designed to work without much internal volume, so they are compact. But car speakers and amplifiers also operate in an environment where power consumption isn't an issue.dwk123 said:
The use of SI/Tripath + fullrange, in contrast, also has some important strengths: low power consumption and high fidelity. Obviously you can't beat the price of something you already have on hand, but I suspect that it's hard to beat the price of a $30 amp if you are starting from scratch.
Weight appears to be an issue that balances out either way. With car audio you would likely need more battery power; with the fullrange you would need bulkier, stiffer enclosures.
Is there some middle ground worth exploring here? I know that there are class D car amps. Are any of them dirt cheap? What I know about car speakers could fit inside a tweeter's voice coil, but I'm open to learn and experiment with something that's perfect for this application.
Randy
I'm currently building such a system although much larger in scale as it's based on 4 10" pro mid drivers and 4 piezos in a 12x12x36" (30x30x100cm) box. It's running on 2 7 Ah 12volt SLAs with a built-in rechanger. The source is a Zen Micro, and have a single T amp as amplifier.
I'm still waiting on the final parts to arrive but if they turn up on time I should have it finished by next weekend.
It's really only an improvement over my project last year where I used the same drivers in a slightly bigger box but with an unsealed car battery as power source and a MP3 capable car stereo head unit as source and amplifier.
The unsealed battery eventually spelled the doom it as it was tilted on it's side thereby ruining the head unit.
Btw, I build a new beast every year for the Roskilde Festival. www.roskilde-festival.dk
I'll see where I can host some pics in order to show you the results when I'm done.
I'm still waiting on the final parts to arrive but if they turn up on time I should have it finished by next weekend.
It's really only an improvement over my project last year where I used the same drivers in a slightly bigger box but with an unsealed car battery as power source and a MP3 capable car stereo head unit as source and amplifier.
The unsealed battery eventually spelled the doom it as it was tilted on it's side thereby ruining the head unit.
Btw, I build a new beast every year for the Roskilde Festival. www.roskilde-festival.dk
I'll see where I can host some pics in order to show you the results when I'm done.
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