Cabinet questions: Madisound Recession Buster Kit

[alexwakelin]

The recession buster kit is on it's way. I am going to build the ported design. These are going to be used for my computer desk, mostly for gaming. Since these are going to be against a wall, the port will need to be in the front. Will this affect the sound at all? Also, I have not decided if I am going to use a slot port or a tube, does it make a difference which one I use?

 

[TLS Guy]

The recession buster kit is on it's way. I am going to build the ported design. These are going to be used for my computer desk, mostly for gaming. Since these are going to be against a wall, the port will need to be in the front. Will this affect the sound at all? Also, I have not decided if I am going to use a slot port or a tube, does it make a difference which one I use?

Front is better, unless there is port noise. I would model it, and if vent velocity is much above 20 m/sec, then I would model a slot vent for it, if it has to go on the front. If the port is to be on the front, keep the port well away from the woofer, so radiation of mid range from the port is minimized.

 

[lsiberian]

Front is better, unless there is port noise. I would model it, and if vent velocity is much above 20 m/sec, then I would model a slot vent for it, if it has to go on the front. If the port is to be on the front, keep the port well away from the woofer, so radiation of mid range from the port is minimized.

There is a design there already for the speakers. But i'm wondering if a front port would be an improvement?

 

[TLS Guy]

There is a design there already for the speakers. But i'm wondering if a front port would be an improvement?

It will be an improvement, as long as vent air velocity is reasonable, and you will need to know this before starting your plan. Then you will also have to pay attention to mid range port radiation. This is were a slot vent would have an advantage, as it will likely have a turn, and that really cuts down unwanted port radiation.

 

[lsiberian]

It will be an improvement, as long as vent air velocity is reasonable, and you will need to know this before starting your plan. Then you will also have to pay attention to mid range port radiation. This is were a slot vent would have an advantage, as it will likely have a turn, and that really cuts down unwanted port radiation.

What tools do you use to measure that?

 

[TLS Guy]

What tools do you use to measure that?

Your program should model it for, you. If not mine will. To save me digging, just remind me of the woofer model number, the internal volume of that enclosure and port dimensions and I can model it if you can't.

 

[TLS Guy]

Your program should model it for, you. If not mine will. To save me digging, just remind me of the woofer model number, the internal volume of that enclosure and port dimensions and I can model it if you can't.

The vent velocity is around 18 m/sec. You should be fine with a front mounted port.

 

[lsiberian]

The vent velocity is around 18 m/sec. You should be fine with a front mounted port.

what program do you use? Bass Box Pro? I haven't purchased a program yet, but interested in finding a good one as I see this hobby potentially growing.

 

[TLS Guy]

what program do you use? Bass Box Pro? I haven't purchased a program yet, but interested in finding a good one as I see this hobby potentially growing.

Yes I do. It has limitations, but does not cost an arm and two legs.

 

[alexwakelin]

I've been trying to model the woofer in WinISD. A 2.5 inch diameter port should keep port air velocity pretty low. This driver hits -3Db at 1600 Hz, which doesn't sound right if the crossover point is at 3000 Hz. I'm also playing with different box sizes, the recommended .35 cubic feet goes down to 50 Hz, bumping it up to .6 cubic feet gets you 40 Hz and a flatter freqency response curve. If it sounds like it will work, I think I will build the .6 cubic foot boxes so I can get by without a subwoofer for now. I don't think the logitech sub will be worthy of these speakers

Maybe someone can confirm I'm getting things right, here's the Madisound spec sheet:

http://www.madisound.com/catalog/PDF/recession-buster.pdf

Edit:

Working on fine tuning the box, here's what I have so far:
.63 cubic foot box = 1088 in^3
2.5 x 8" port = 39 in^3
Dimensions: 7"W x 16"H x 10"D = 1120 in^c

This gives me -3Db at ~41Hz

 

[lsiberian]

I've been trying to model the woofer in WinISD. A 2.5 inch diameter port should keep port air velocity pretty low. This driver hits -3Db at 1600 Hz, which doesn't sound right if the crossover point is at 3000 Hz. I'm also playing with different box sizes, the recommended .35 cubic feet goes down to 50 Hz, bumping it up to .6 cubic feet gets you 40 Hz and a flatter freqency response curve. If it sounds like it will work, I think I will build the .6 cubic foot boxes so I can get by without a subwoofer for now. I don't think the logitech sub will be worthy of these speakers

Maybe someone can confirm I'm getting things right, here's the Madisound spec sheet:

http://www.madisound.com/catalog/PDF/recession-buster.pdf

Edit:

Working on fine tuning the box, here's what I have so far:
.63 cubic foot box = 1088 in^3
2.5 x 8" port = 39 in^3
Dimensions: 7"W x 16"H x 10"D = 1120 in^c

This gives me -3Db at ~41Hz

You will have a jealous subwoofer on your hands. That is probably near the bottom of the logitech lol.

 

[TLS Guy]

I've been trying to model the woofer in WinISD. A 2.5 inch diameter port should keep port air velocity pretty low. This driver hits -3Db at 1600 Hz, which doesn't sound right if the crossover point is at 3000 Hz. I'm also playing with different box sizes, the recommended .35 cubic feet goes down to 50 Hz, bumping it up to .6 cubic feet gets you 40 Hz and a flatter freqency response curve. If it sounds like it will work, I think I will build the .6 cubic foot boxes so I can get by without a subwoofer for now. I don't think the logitech sub will be worthy of these speakers

Maybe someone can confirm I'm getting things right, here's the Madisound spec sheet:

http://www.madisound.com/catalog/PDF/recession-buster.pdf

Edit:

Working on fine tuning the box, here's what I have so far:
.63 cubic foot box = 1088 in^3
2.5 x 8" port = 39 in^3
Dimensions: 7"W x 16"H x 10"D = 1120 in^c

This gives me -3Db at ~41Hz

I have played with this for a while. I would not build a 0.6 cu.ft box, because the response starts to roll off in the mid range. I have found that 0.44 cu. ft. box will give you an F3 of 48 Hz. That box will actually appear to have more bass than a 0.6 cu. ft. box. It tunes with a 2" diameter port 9" inches long.

I consider this the optimal box.

I think you said you were going to use this for gaming. You need to be aware that this driver is small and is severely displacement limited between 50 and 100 Hz. So for gaming I suspect you will need a sub to avoid bottoming the drivers and destroying them. A crossover between 90 and 100 Hz should be optimal, if you want high spl. below 100 Hz. So having an F3 around 50 Hz will be perfect for that.

 

[alexwakelin]

Do the box dimensions matter much? How does 7"W x 14"H x 8"D sound? I guess I will keep the logitech sub for a bit longer...I have had my eyes on this TB sub though...

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-854

 

[TLS Guy]

Do the box dimensions matter much? How does 7"W x 14"H x 8"D sound? I guess I will keep the logitech sub for a bit longer...I have had my eyes on this TB sub though...

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-854

That is fine, but don't forget to add the volume of the driver, crossovers and bracing.

 

[alexwakelin]

That is fine, but don't forget to add the volume of the driver, crossovers and bracing.

Yup, I'll be making a stop at Home Depot on the way home tomorrow to buy some MDF. Too cold to build cabinets in the garage right now though. I'm stuck working in a very cramped laundry room.

 

[alexwakelin]

I made some progress on my boxes today, so far things are going a bit smoother then when I built my sub box. It was about 2 degrees today, a bit too cold to work in the garage. Here's my makeshift workroom and my "cut tables":

Here's a partially assembled box, not much to look at yet. I still need to install bracing, and cut holes for the terminal plate, port and drivers. I need more clamps too.

I have come to the conclusion that the blade that came with my saw is a piece of junk (well, the saw kind of is too). As you can see, it binds up very easily and already seems pretty dull after just a few uses. Can someone recommend a decent blade that isn't too expensive? Most blades probably cost more than I paid for the saw, so maybe something under $20.00.

 

[alexwakelin]

Here's a couple more pictures:

A comparison of the speakers being replaced, some ancient JBL bookshelf speakers a friend gave to me.

I guess you could say my new speakers will literally eat the old ones for breakfast

 

[TLS Guy]

I made some progress on my boxes today, so far things are going a bit smoother then when I built my sub box. It was about 2 degrees today, a bit too cold to work in the garage. Here's my makeshift workroom and my "cut tables":

Here's a partially assembled box, not much to look at yet. I still need to install bracing, and cut holes for the terminal plate, port and drivers. I need more clamps too.

I have come to the conclusion that the blade that came with my saw is a piece of junk (well, the saw kind of is too). As you can see, it binds up very easily and already seems pretty dull after just a few uses. Can someone recommend a decent blade that isn't too expensive? Most blades probably cost more than I paid for the saw, so maybe something under $20.00.

I can tell it is the wrong bade, and or dull. It is burning the boards, and that is very unhealthy for you. For MDF you need a 40 tooth carbide tipped blade. You should be able to get one in your price range at you local Home Depot or similar store.

 

[alexwakelin]

I can tell it is the wrong bade, and or dull. It is burning the boards, and that is very unhealthy for you. For MDF you need a 40 tooth carbide tipped blade. You should be able to get one in your price range at you local Home Depot or similar store.

The guy at home depot said it was the right blade for MDF, but of course you can't always trust everything the Home Depot clerks tell you.

Edit:
I just looked, it says 20 tooth right on the blade. The guy at HD needs to learn his stuff.

 

[alexwakelin]

Today I sealed up the boxes and got the braces cut and installed. I just need to cut the baffles and install the ports, then it's time for paint.

They're a bit ugly on the inside.