I am tired of listening to computer speakers, even the three piece systems with a woofer. I am therefore recycling an old set of Realistic speakers from Radio Shack (some 20 years ago). Will post the project and pictures here.
Bought and tested the mini-amplfier - AK-699D. Then bought a small tweeter.
Bought and tested the mini-amplfier - AK-699D. Then bought a small tweeter.
Prototype speaker - and amplifier problems
Speaker Prototype
I fixed the 6 inch woofers and the tweeter to a corrugated card computer box for testing. I know the speaker will not output much bass but I wanted to see how it sounds at the minimum. A proper cabinet would only increase the quality of its sound. Also, following the rule that a good speaker will sound good on its own (single speaker) and bad speakers sound better in pairs, I decided to test only one speaker:
Results?
Volume was low, even at full power with the AK-699D mini amplifier. There did not seem to be any distortion but bass was almost non-existent, even with the bass control full up, and mid ranges seemed a little empty. The tweeter was louder than the woofer so I will have to compensate for that.
Heating up
After a short run of about 20 minutes both the amplifier and the speaker voice coil had heated up considerably. Possibly due to using the two 8 ohm speakers, woofer and tweeter in parallel, this will give 4 ohms impedance?
Connected to boombox
I had rewired a Sony CFD-6 CD tape player so that the speaker wires extended out of the chassis for external connection. Hooking these up resulted in a welcome surprise, sound was full, loud, and bass was impressive for an open box. I only tested this set up using FM radio, which is not of high quality, but results were pleasing to say the least. No heating up at all.
The output for the CFD-6 is listed as 3.2 ohm full range speakers in the chassis (since disconnected) .
The speakers are well on their way to being set in wood and finished as wall hanging units, but I may need a new amplifier.
Comments?
As you can tell I am new to this, so any comments will be appreciated. This is a really fascinating if addictive hobby. It has a real utility as well - we all listen to music.
Speaker Prototype
I fixed the 6 inch woofers and the tweeter to a corrugated card computer box for testing. I know the speaker will not output much bass but I wanted to see how it sounds at the minimum. A proper cabinet would only increase the quality of its sound. Also, following the rule that a good speaker will sound good on its own (single speaker) and bad speakers sound better in pairs, I decided to test only one speaker:
Results?
Volume was low, even at full power with the AK-699D mini amplifier. There did not seem to be any distortion but bass was almost non-existent, even with the bass control full up, and mid ranges seemed a little empty. The tweeter was louder than the woofer so I will have to compensate for that.
Heating up
After a short run of about 20 minutes both the amplifier and the speaker voice coil had heated up considerably. Possibly due to using the two 8 ohm speakers, woofer and tweeter in parallel, this will give 4 ohms impedance?
Connected to boombox
I had rewired a Sony CFD-6 CD tape player so that the speaker wires extended out of the chassis for external connection. Hooking these up resulted in a welcome surprise, sound was full, loud, and bass was impressive for an open box. I only tested this set up using FM radio, which is not of high quality, but results were pleasing to say the least. No heating up at all.
The output for the CFD-6 is listed as 3.2 ohm full range speakers in the chassis (since disconnected) .
The speakers are well on their way to being set in wood and finished as wall hanging units, but I may need a new amplifier.
Comments?
As you can tell I am new to this, so any comments will be appreciated. This is a really fascinating if addictive hobby. It has a real utility as well - we all listen to music.
Attachments
Speaker front baffles
I got the speaker front baffles cut out of MDF - cost me about ten dollars materials and labor. I intended to make the sides and top later, using a slim design like some of the wall mounted speakers made by various manufacturers, On- wall speakers they are called.
It turns out that there are speakers called open baffle speakers. At present these will function as open baffle speakers. They do not sound too bad at the moment at least the single speaker I tested was a boxy in its sound, but portrayed music with much more clarity that I expected with my 1 watt PC speaker improvisation amp.
I got the speaker front baffles cut out of MDF - cost me about ten dollars materials and labor. I intended to make the sides and top later, using a slim design like some of the wall mounted speakers made by various manufacturers, On- wall speakers they are called.
It turns out that there are speakers called open baffle speakers. At present these will function as open baffle speakers. They do not sound too bad at the moment at least the single speaker I tested was a boxy in its sound, but portrayed music with much more clarity that I expected with my 1 watt PC speaker improvisation amp.
Attachments
If you like "OB" Put a half box around the back maybe 5 in deep walls. Line walls with felt. It will do wonders for the bass as all your bass cancels from OB. You have no bass below 600Hz or so.
Otherwise cover back completely and add stuffing and bass will go up 100x.
Fun project. Keeping up. We all start with cardboard or repurposed boxes.
Otherwise cover back completely and add stuffing and bass will go up 100x.
Fun project. Keeping up. We all start with cardboard or repurposed boxes.
Thanks for the encouragement. Existing bass is OK, but I had toyed with the idea of fixing a infinite baffle sealed box to cover the drivers and keep dust out.
The real limitation is keeping cost low by using minimum materials or by using scrap wood, being environmentally friendly, must.
The MDF I used apparently contains harmful glues, I would have used wood instead if I had known early enough, and saved the cost of the MDF.
The real limitation is keeping cost low by using minimum materials or by using scrap wood, being environmentally friendly, must.
The MDF I used apparently contains harmful glues, I would have used wood instead if I had known early enough, and saved the cost of the MDF.
Do you have access to foam core paper faced art poster boards in Sri Lanka. Tough being on an island in Indian Ocean. Humid environments are not easy on foam core boards. If you have it though makes building speaker boxes clean and easy. Triple ply heavy duty cardboard is also excellent and I use it augment toughness and strength to foam core. This has a flat middle layer with two corrugated layers on either side and flat thick cardboard on outsides. Used in TV and appliance shipping boxes. Free and can be found in back of stores where they throw out or recycle. You can make a whole SLOB speaker with it.
http://www.diyaudio.com/forums/full-range/249984-cheap-fast-ob-literally.html
More on Foam Core speakers:
http://www.diyaudio.com/forums/full-range/223313-foam-core-board-speaker-enclosures.html
Look at all the things one can make with foam core on page 1 index.
http://www.diyaudio.com/forums/full-range/249984-cheap-fast-ob-literally.html
More on Foam Core speakers:
http://www.diyaudio.com/forums/full-range/223313-foam-core-board-speaker-enclosures.html
Look at all the things one can make with foam core on page 1 index.
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Foam boards are available here, however I prefer to use the corrugated cardboard instead, since it means I am then recycling materials. My first enclosure were using corrugated cardboard if you see the pictures. Not sure that I have seen the triple layer stuff.
I can see that there are many experiments being carried out with all sorts of speaker enclosures. I tend to favor the flat on wall speakers such as this, though I prefer separate, smaller boxes.
Full range speakers continue to impress, but these ones are a little over budget.
While we are on the subject of materials, here is an article on how to obtain cheap lumber.
I can see that there are many experiments being carried out with all sorts of speaker enclosures. I tend to favor the flat on wall speakers such as this, though I prefer separate, smaller boxes.
Full range speakers continue to impress, but these ones are a little over budget.
While we are on the subject of materials, here is an article on how to obtain cheap lumber.
That's what a properly designed full range box can do with a 3in driver. For much listening of casual music 3in drivers excell.
If you think those sound good. Try a 3FE25 in a small 0.40x Karlsonator. Better yet try dual TC9FD in a 0.53x Karlsonator. Big rich bass and beautiful mids and voices. Great transients too.
http://www.diyaudio.com/forums/full-range/239338-mini-karlsonator-0-53x-dual-tc9fds.html
Lots of happy builders in that thread. It's an easy speaker to make and there are even cut and fold plans for it to be made out of cardboard.
If you think those sound good. Try a 3FE25 in a small 0.40x Karlsonator. Better yet try dual TC9FD in a 0.53x Karlsonator. Big rich bass and beautiful mids and voices. Great transients too.
http://www.diyaudio.com/forums/full-range/239338-mini-karlsonator-0-53x-dual-tc9fds.html
Lots of happy builders in that thread. It's an easy speaker to make and there are even cut and fold plans for it to be made out of cardboard.
In cardboard or foam very simple. Cut a long strip of material equal to width of speaker. Start at bottom back corner going forward measure score and fold at each point and glue with hot melt as you go and wrap around all the way to the end of the internal divider. The add double thickness driver baffle, add bracing and then cut piece equal to top and back score and fold and glue. Now glue second side on with slower dry glue like PVA and use weight to clamp. Takes less than 30min to do. Now cut hole for driver add stuffing you are 95% done. Add double layer K aaperture to front.
Trick is to draw plan on first side to layout glue line when gluing middle panels all connected.
Look at steps here:
http://www.diyaudio.com/forums/full...onator-0-53x-dual-tc9fds-115.html#post4139973
Trick is to draw plan on first side to layout glue line when gluing middle panels all connected.
Look at steps here:
http://www.diyaudio.com/forums/full...onator-0-53x-dual-tc9fds-115.html#post4139973
The Karlsonator is a transmission line speaker is it not? It looks fine but the edges in front of the speaker really get me worried - there are bound to be diffraction effects on the edge of the port, with the edge of the port functioning as separate sound sources. Interference between the sound from the edges and the driver is bound to interfere. How does it work?
On the subject of my own speakers, I dispensed with theory completeley, simply mounting my speakers on a simple faceplate. Little did I know that I was building a Open Baffle speaker. Placing these close to the wall, since they are wall mounted, should take care of the bass.
What keeps me motivated is that this design sounds as good as or better than all the speaker I have heard so far in terms of clarity, I recently listened to a pair of Harman-Kardon desktop speakers - good clarity and amazing bass, you can even see the driver vibrate.
The important point is that the reviewers agree with me about the clarity of sound - that is all important to me now, that, and a little bass.
On the subject of my own speakers, I dispensed with theory completeley, simply mounting my speakers on a simple faceplate. Little did I know that I was building a Open Baffle speaker. Placing these close to the wall, since they are wall mounted, should take care of the bass.
What keeps me motivated is that this design sounds as good as or better than all the speaker I have heard so far in terms of clarity, I recently listened to a pair of Harman-Kardon desktop speakers - good clarity and amazing bass, you can even see the driver vibrate.
The important point is that the reviewers agree with me about the clarity of sound - that is all important to me now, that, and a little bass.
The Karlson aperture is in fact a diffraction acoustic lens. It has some mid range anomalies that are inoffensive. The improved dispersion and wide soundstage coupled with great dynamics and a clean impulse are all worth it. You should give it a try - look how many people have built and liked it.
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