You might want to check out these IRS2093 based amps - they have very low distortion. Their dual rail power supplies will set you back more than the amps but... 350 watts/ch for $40 for the amp proper, is not too shabby. Based on what I have read in class D forum, this type of class D amp is < 0.1% THD at full power. You will need something like a ~+/- 50 volt power supply to get the full 350 watts.
Mono-block:
Yuan Jing Audio - IRS2092 Class-D Mono Amplifier Board [350W+350W] - $40.80
Pair that with one of these toroidals:
http://www.yuan-jing.com/toroidal/600-va
Stereo:
http://www.yuan-jing.com/irs2092-class-d-stereo-amplifier-board-350w-350w-speaker-protection?keyword=irs209
Mono-block:
Yuan Jing Audio - IRS2092 Class-D Mono Amplifier Board [350W+350W] - $40.80
Pair that with one of these toroidals:
http://www.yuan-jing.com/toroidal/600-va
Stereo:
http://www.yuan-jing.com/irs2092-class-d-stereo-amplifier-board-350w-350w-speaker-protection?keyword=irs209
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A few minor points.
The distance between the column and the side wall *will* have an audible effect on the FR.
The gap on the bottom *will* have a measureable, and perhaps audible effect on the FR.
On the second thing, I'd opt to flip the column over, get the drivers to have minimum distance to the floor.
On the first, the gap to the wall will act the same way as will a combination of "baffle step" and "floor bounce". The solutions to this come to mind as:
- move the array flush with the wall
- create a smooth transition out from the wall over some length, to meet the edge of the column
- place absorptive material on the wall sufficient to adequately absorb and attenuate reflections at and above the frequency of interest.
No sense in putting in dips and peaks into an otherwise very smooth driver/speaker that can be avoided...
_-_-
The distance between the column and the side wall *will* have an audible effect on the FR.
The gap on the bottom *will* have a measureable, and perhaps audible effect on the FR.
On the second thing, I'd opt to flip the column over, get the drivers to have minimum distance to the floor.
On the first, the gap to the wall will act the same way as will a combination of "baffle step" and "floor bounce". The solutions to this come to mind as:
- move the array flush with the wall
- create a smooth transition out from the wall over some length, to meet the edge of the column
- place absorptive material on the wall sufficient to adequately absorb and attenuate reflections at and above the frequency of interest.
No sense in putting in dips and peaks into an otherwise very smooth driver/speaker that can be avoided...
_-_-
Agreed, a router have been on my wish list for like forever... Now I just need to totally empty my workshop at home and set it all up so i dont have to spend too much time in the garage
It is still kinda cold over here...Hi Bear and thank you for weighing in
My home theater room have 6" high soffits housing downlights and ventilation, due to that the only way I could run my arrays all the way to the ceiling they need to be 1-1/2-2' out from the front wall. I intend to place them closer than that thus limited to ceiling-soffit height. Coincidently the gap distance on the floor-bottom of the array to the top-ceiling is similar. Ref image attachments.
My Columns were planned to take the area where the current DM604's reside although nothing is carved in stone yet - learning by doing and in that regard all the added info you guys provide are most helpful to me
Unfortunately my room/speaker placement isnt symetrical so FL will have its side wall about 6' further to the left, vs 1-2' for FR
Attachments
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Not sure yet as I havent calulated for possible models
Maybe symmetry from floor/ceiling is best anyhow? (20 drivers with approx 8" cavity both top and bottom of array)
Probably best to get flush to the floor... regardless of the number of drivers.
More is better though...
There is a "floor bounce" that will take place with a gap... how bad and at what frequency is the only question... will the presence of the other drivers (the height to floor changing per driver) tend to flatten the effect so much that it doesn't matter?
If ur crossing over above the problem frequency then I guess it is not an issue at all.
But if ur full range, like Keele's CBT, the floor is like a mirror and there is a virtual array below. The CBT is curved, but this holds true for vertical arrays too. He has some nice graphs and figures in his paper that illustrate all this nicely.
I see ur point about the non-symmetrical room position. But given that the array has a very wide horizontal dispersion, the relationship to the wall is important. What comes off the wall when the speaker is close becomes even more important.
Fwiw, if the wall is very close on one side and not the other, it might work best to toe the speakers at 45 deg in, at the main listening point... this will minimize the radiation to the closest wall and perhaps even improve the off center postiion imaging.
Nice project!
More is better though...
There is a "floor bounce" that will take place with a gap... how bad and at what frequency is the only question... will the presence of the other drivers (the height to floor changing per driver) tend to flatten the effect so much that it doesn't matter?
If ur crossing over above the problem frequency then I guess it is not an issue at all.
But if ur full range, like Keele's CBT, the floor is like a mirror and there is a virtual array below. The CBT is curved, but this holds true for vertical arrays too. He has some nice graphs and figures in his paper that illustrate all this nicely.
I see ur point about the non-symmetrical room position. But given that the array has a very wide horizontal dispersion, the relationship to the wall is important. What comes off the wall when the speaker is close becomes even more important.
Fwiw, if the wall is very close on one side and not the other, it might work best to toe the speakers at 45 deg in, at the main listening point... this will minimize the radiation to the closest wall and perhaps even improve the off center postiion imaging.
Nice project!
Totally agree with the above...
Starting the arrays as close to the floor as you can is probably best to avoid floor bounce. My array is about one driver shy of touching the floor, that's where the stand is to be able to aim them.
Also the positioning in relation to the walls, I agree to toe in the arrays.
In fact, that's what I mentioned as a (partial) solution in my own thread. I have similar placement, one side is close to a side wall and the other is not.
I plan on using some form of absorption/diffusion on that one wall but also toe in the speakers at about 45 degrees (cross slightly in front of the central listening position, in other words; aim at the opposite far seat).
Starting the arrays as close to the floor as you can is probably best to avoid floor bounce. My array is about one driver shy of touching the floor, that's where the stand is to be able to aim them.
Also the positioning in relation to the walls, I agree to toe in the arrays.
In fact, that's what I mentioned as a (partial) solution in my own thread. I have similar placement, one side is close to a side wall and the other is not.
I plan on using some form of absorption/diffusion on that one wall but also toe in the speakers at about 45 degrees (cross slightly in front of the central listening position, in other words; aim at the opposite far seat).
No real update but I did get to run up the router yesterday, cleaned up the groves on the first side panel and started on the second side which is now half done. The router was as expected a much better tool for the job.
Before the first glue can be applied I need to chamfer the front baffle driver holes but this is something I hope to get done this weekend
Will update again with pics at that time 
At any rate, I am locked to my original plan of 20 drivers per Column, I will complete the one Column before starting the second one. I will however seriously consider moving the start of the array as low to the floor as possible as I imagine its better to have the physical and virtual array as continous as possible - with a cavity on top vs cavity both top and bottom.
Before the first glue can be applied I need to chamfer the front baffle driver holes but this is something I hope to get done this weekend
Will update again with pics at that time At any rate, I am locked to my original plan of 20 drivers per Column, I will complete the one Column before starting the second one. I will however seriously consider moving the start of the array as low to the floor as possible as I imagine its better to have the physical and virtual array as continous as possible - with a cavity on top vs cavity both top and bottom.
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Top driver will be centered at about 6'2" high while ear height will be at approx 4'. I wont get the bottom driver all the way down to the floor so there will be a hole between the physical/virtual line. How much it will matter is to be determined
Since these are going into my HT-room there wont much standing up while listening
Since these are going into my HT-room there wont much standing up while listening
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