miragem3i,
There's nothing odd about what people say on this forum, what they say is their perspective of what your going to do and what results you will get
My Very humble advise, Go buy planks of wood, drivers, hack / saw / nail and glue it all together and job done.
If the result works for you, post here saying so 🙂
There's nothing odd about what people say on this forum, what they say is their perspective of what your going to do and what results you will get
My Very humble advise, Go buy planks of wood, drivers, hack / saw / nail and glue it all together and job done.
If the result works for you, post here saying so 🙂
An additional observation:
My listening room is 6m x 4m with a 3.6m tall ceiling. The walls are 25-30cm thick concrete, brick, tile, hard plaster. The floor is a slab on the ground with tile over the slab.
The ceiling, however, is a drum. It's a 6m x 4m 2cm thick piece of plaster/wood with a framework of supports spaced 40cm apart, with a light fixture in the middle. Above it is 2 or 3 m of dead space that is the attic, then the peaked roof line. I just poked it with a long rod and it vibrates with a small tap.
Any bass will cause it to vibrate like a drum at FQ of 57.3. 344/6=57.3.
Construction quality is such that this would be an exceedingly bad idea.
The ceiling could, easily, collapse.
The good part is that the rooms corners are, naturally, very sold bass nodes so that placement of units in the corners will reinforce the bass at the listening position.
But, as I posted, no 8 x 18" subs for this install...
My listening room is 6m x 4m with a 3.6m tall ceiling. The walls are 25-30cm thick concrete, brick, tile, hard plaster. The floor is a slab on the ground with tile over the slab.
The ceiling, however, is a drum. It's a 6m x 4m 2cm thick piece of plaster/wood with a framework of supports spaced 40cm apart, with a light fixture in the middle. Above it is 2 or 3 m of dead space that is the attic, then the peaked roof line. I just poked it with a long rod and it vibrates with a small tap.
Any bass will cause it to vibrate like a drum at FQ of 57.3. 344/6=57.3.
Construction quality is such that this would be an exceedingly bad idea.
The ceiling could, easily, collapse.
The good part is that the rooms corners are, naturally, very sold bass nodes so that placement of units in the corners will reinforce the bass at the listening position.
But, as I posted, no 8 x 18" subs for this install...
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Open baffles are a good choice for a room like this. I lived in a similar space for a long time. The directional dipole pattern helps avoid a lot of the usual problems. However, they really should be placed away from corners, to avoid interference from the back wave.
Anyway, you'll want a driver with a Qts or .7 or higher. The narrower the baffle, the higher it should be. It should have a large Xmax and Xmech, and a sturdy surround. These are all somewhat old fashioned specs. For a modern driver, consider: the Betsy, the L. Cao or similar Diatone clone, or one of the Supravox drivers. There might be a cheap autosound FR out there that could be used for proof of concept.
The other approach that can work well in a concrete room is a small quasi corner horn. For this, you want a low Q driver (like a Fostex or Lowther). Essentially, it's a low tuned reflex box with the port loaded into the corner.
Anyway, you'll want a driver with a Qts or .7 or higher. The narrower the baffle, the higher it should be. It should have a large Xmax and Xmech, and a sturdy surround. These are all somewhat old fashioned specs. For a modern driver, consider: the Betsy, the L. Cao or similar Diatone clone, or one of the Supravox drivers. There might be a cheap autosound FR out there that could be used for proof of concept.
The other approach that can work well in a concrete room is a small quasi corner horn. For this, you want a low Q driver (like a Fostex or Lowther). Essentially, it's a low tuned reflex box with the port loaded into the corner.
OB do not have to be big baffles.
Se this frontpage with no baffle ;-)
https://www.hifitest.de/shop/images/kt3-2010_offen-1.jpg
Se this frontpage with no baffle ;-)
https://www.hifitest.de/shop/images/kt3-2010_offen-1.jpg
I found some material here for OB's, a variety of sizes.
Home kitchen cutting boards. Really. Small units for the bedroom, larger in the living room now with the discarded woofers from the $10 cheap TV boxes, and a tube amp.
Less than $10 a pair.
Home kitchen cutting boards. Really. Small units for the bedroom, larger in the living room now with the discarded woofers from the $10 cheap TV boxes, and a tube amp.
Less than $10 a pair.
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I am happy with the cheap driver's sound, proof of concept ok. Now to buy the best 3" driver I can find here - only $50 each. The holes are, accidentally, a bit off center line. This has the bonus of putting the 1/4 wave cancellations just a little out of phase on each side of each baffle. The room is lined with bamboo screens that act as diffusers.
I looked into Mark Audio and such and actually there is not much here in the 3" market. 4" and larger I can obtain names that are well known here, but 3" is all COSTE, AIRS, G Audio and other Chinese brands that mostly use the DQ30TZF-03 for a base and rebrand or tweak it slightly. MY guess is that G Audio is the OEM. This 3" driver, btw, is quite good so it is not a poor choice at all.
For the next build I may purchase the largest of these boards, 40 inches tall. Up to 6.5" driver into each. With that much room Diatone clones, the Betsy, the L. Cao, and Supravox are all usable.
I may buy a second board for each and glue them together for stiffness. Perhaps some damping material between in a sandwich.
These boards vibrate quite a bit at volume.
Maybe another layer screwed and glued as a sandwich, or even some local stone cut to fit. Or the Wharfedale solution of sand or bricks in on a panel behind the front, used as supports. Concerned about resonance from the sand/brick box, though. Boxiness, not wanted.
With the mount hole cut by me, a precise hole for the back with screws and such is not needed - just something close enough to access the driver and give the back wave room.
Making my own speaker cable - that's 14AWG solid core hookup wire you see in the green wires above.
Going to buy a larger spool and use the drill to twist a pair together and get some big terminal extensions to clip over the speaker terminals so that I can attach many lines of thick wire to the speakers.
Still using my cardboard OB for PC speakers, with the $1 drivers from the reused TV boxes that are on stands in the listening room.
I now have 4 sets of speakers.
I looked into Mark Audio and such and actually there is not much here in the 3" market. 4" and larger I can obtain names that are well known here, but 3" is all COSTE, AIRS, G Audio and other Chinese brands that mostly use the DQ30TZF-03 for a base and rebrand or tweak it slightly. MY guess is that G Audio is the OEM. This 3" driver, btw, is quite good so it is not a poor choice at all.
For the next build I may purchase the largest of these boards, 40 inches tall. Up to 6.5" driver into each. With that much room Diatone clones, the Betsy, the L. Cao, and Supravox are all usable.
I may buy a second board for each and glue them together for stiffness. Perhaps some damping material between in a sandwich.
These boards vibrate quite a bit at volume.
Maybe another layer screwed and glued as a sandwich, or even some local stone cut to fit. Or the Wharfedale solution of sand or bricks in on a panel behind the front, used as supports. Concerned about resonance from the sand/brick box, though. Boxiness, not wanted.
With the mount hole cut by me, a precise hole for the back with screws and such is not needed - just something close enough to access the driver and give the back wave room.
Making my own speaker cable - that's 14AWG solid core hookup wire you see in the green wires above.
Going to buy a larger spool and use the drill to twist a pair together and get some big terminal extensions to clip over the speaker terminals so that I can attach many lines of thick wire to the speakers.
Still using my cardboard OB for PC speakers, with the $1 drivers from the reused TV boxes that are on stands in the listening room.
I now have 4 sets of speakers.
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You might want to check out this thread for some info. http://www.diyaudio.com/forums/full-range/249984-cheap-fast-ob-literally.html. The Vifa TC9FD and the Faital Pro 4FE35 both appear to be great drivers for OB - very smooth and higher Qts and reasonably priced. You might want to offset your driver so it is not in the middle. In your case you are not using a sub so you probably want baffle at least 12 in wide vs the 5 in wide baffle that Buildmesomething was working on.
I have cardboard in my OB for my PC station, but that was a proof of concept and I want something a *bit* more sturdy now that I have gone through the concept phases.
The Vifa TC9FD18 looks intriguing, as my hearing is gone above 13.5khz, so I won't miss the sparkle this driver lacks...and the cutout of 78mm barely fits my standard 3" hole in my 15" wide cutting board OB!
The liveliness and soundstage of a single driver OB is just what I was looking for.
Many thanks.
The Vifa TC9FD18 looks intriguing, as my hearing is gone above 13.5khz, so I won't miss the sparkle this driver lacks...and the cutout of 78mm barely fits my standard 3" hole in my 15" wide cutting board OB!
The liveliness and soundstage of a single driver OB is just what I was looking for.
Many thanks.
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how about a tall line-array OB with 12" baffle width? Just use a bunch of TC9FD8 (which has a very high Qts, perfect for OB) and call it good.
The mid-bass would still be quite ok despite tiny driver size, if you use more than 10 TC9's per side; sound is smooth and pleasant; and the line-array gives you that "headphone" style near-field sound.
The mid-bass would still be quite ok despite tiny driver size, if you use more than 10 TC9's per side; sound is smooth and pleasant; and the line-array gives you that "headphone" style near-field sound.
To my ears, this driver doesn't lack sparkle. If you want a little more airiness, EQ it from 15 kHz on up and it will produce a flat response to almost 20 kHz.
You might want to try to find some vintage Grundig 7"*11" oval drivers. If you find some in good shape you are in for a treat. I think they match up well to what you expext/want from your future OB speaker.
For a really nice looking small open baffle driver take a look at the Faital Pro 4FE35, I think it fits your needs and is reasonably priced. FaitalPRO | LF Loudspeakers | 4FE35
The Wharfedale sand filled baffle method works well. It might be somewhat messy and difficult to do a DIY version. I wouldn't be overly concerned about resonance if using a sand filled baffle. It is very effective.
As you suggest, an alternate approach is to glue another sheet to the back, with a thin layer of rubber or other lossy material in between to form a sandwich. These are both variations of the constrained layer technique. I'd suggest something like MDF or hardboard for the back layer. The mass will help. Tiles or slate or something would also be good if you don't mind the difficulty and expense.
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