DIY Sub Enclosure/amp ideas

[Jeff R.]

I assume it will fit into a standard rack. So it will not look out of place? The wife will have concerns obviously....

 

[WmAx]

I assume it will fit into a standard rack. So it will not look out of place? The wife will have concerns obviously....

The wings for the pro rack mounting tabs make it a bit wider than normal home gear. It may not fit a regular audio rack. With the tabs, it's 19" wide. Check your rack width.

If the budget allows, Yamaha makes some pro amps that have no fan noise, and the rack mount tabs are removable for installation in normal consumer audio racks. The Yamaha P3500S outputs 450 x 2 into 4 Ohms, or 350 x 2 into 8 Ohms, 20Hz-20,000Hz, both channels driven. It retails for $500, but you may find it discounted if you look around. The P5000S is $600 and it outputs 500x2 into 8 Ohms, and 700 x 2 into 4 Ohms.

-Chris

 

[Jeff R.]

One other amp question. I saw the Bash makes a 300 W amp, could I buy 2 of those and power each voice coil on the woofer with a 300 W bash amp at 4 ohms or would that potentially cause problems?

I will look into the Yamaha option also.

 

[WmAx]

One other amp question. I saw the Bash makes a 300 W amp, could I buy 2 of those and power each voice coil on the woofer with a 300 W bash amp at 4 ohms or would that potentially cause problems?

I will look into the Yamaha option also.

Which one are you talking about? The BASH300 is like $140-$150 at Parts Express. 4 of those would buy you the P5000S Yamaha amplifier.

I recommend against using multiple plate amps - while it will work - setting them both to exactly the same setting for each speaker will be a substantial annoyance. You will have to use a volt meter to set levels, btw, as you can not count on the same relative position of the control on each amp to be the same due to parts tolerance variances.

-Chris

 

[Jeff R.]

Yes I was referring to the Bash 300. I did not however realize that when you were recommeding the Beringer and the Yamaha you were saying to power two subs with the one amp. I was thinking you were saying that i would need an individual amp for each sub.

I really do not know at this point if I am going to build two boxes. I was hoping to build one and see how it turns out. Then after some time build the second if I am happy with the performance. I there an amp that is about 1/2 the size of the behringer or yamaha that I can bridge into one channel for just one sub? Then purchase a second one later if I am happy with my results.

I was crunching some basic calcs last night am a little concerned that when I get this thing complete it is going to be huge. right now I am looking at close to about a 2' cube give or take a few inches. I we were to sacrifice some of the low end response could the over box box be slightly smaller. Realistically I would be very happy to bottom out at about 21-22 hz. RIght now my home sub only goes to 40 hz and is a measly 100W and 14 years old.

Thanks

Jeff

 

[annunaki]

The Behringer can be had for as little as $260.00 shipped with a price match option from www.zzounds.com

That is about 11 cents per watt when it is in mono! I do not think there is a better deal to be had.

 

[WmAx]

Yes I was referring to the Bash 300. I did not however realize that when you were recommeding the Beringer and the Yamaha you were saying to power two subs with the one amp. I was thinking you were saying that i would need an individual amp for each sub.

Yes, just one of those Yamaha or Behringer amps is required to power both subwoofers.

I really do not know at this point if I am going to build two boxes. I was hoping to build one and see how it turns out. Then after some time build the second if I am happy with the performance. I there an amp that is about 1/2 the size of the behringer or yamaha that I can bridge into one channel for just one sub? Then purchase a second one later if I am happy with my results.

You can bridge and use the Yamaha or Behringer, or just use one of their channels for one sub. Then use both channels of the amplifier when you get two of the subs. But I would recommend just building two cabinets right from the beginning. You can place them in different parts of the room for ideal response, or stack them to act as one single sub with the same floor footprint.

I was crunching some basic calcs last night am a little concerned that when I get this thing complete it is going to be huge. right now I am looking at close to about a 2' cube give or take a few inches. I we were to sacrifice some of the low end response could the over box box be slightly smaller. Realistically I would be very happy to bottom out at about 21-22 hz. RIght now my home sub only goes to 40 hz and is a measly 100W and 14 years old.

If you are willing to limit yourself to 24 hz -3dB point, you can save a lot of space. Let me know and I'll run the numbers again based on this. But if you go with my original suggestion, you will have that ultimate sub performance that everyone usually ends up desiring eventually.

-Chris

 

[Jeff R.]

Chris

I have a few more questions. I think I am going to start moving forward with purchases. I think I am going to try the Behringer amp like you suggested.

A few questions about the box. I have run my calcs on the box sizing. I saw a detailed box design for the Kappa DIY enclosure floating around on the forum. I am going to more or less copy that design but to my size requirements. I am planning on wrapping the port with just like that design with the start of the port on the inside top of the box and wrapping around and down the back wall and across the bottom and venting out the front and front mount the woofer. When calculating the port length can I just use the part of the port that will be touching the outer walls of the enclosure or is it really necessary to calculate the center line of the port.

I guess I am just not sure how exact every dimension needs to be. For example: you said I need a 4.5 cubic feet of internal volume. How exact will that have to be, if I am say with in 0.5% of that will I be fine or do I have to hit it exact?

Thanks

Jeff

 

[WmAx]

Chris

I have a few more questions. I think I am going to start moving forward with purchases. I think I am going to try the Behringer amp like you suggested.

A few questions about the box. I have run my calcs on the box sizing. I saw a detailed box design for the Kappa DIY enclosure floating around on the forum. I am going to more or less copy that design but to my size requirements. I am planning on wrapping the port with just like that design with the start of the port on the inside top of the box and wrapping around and down the back wall and across the bottom and venting out the front and front mount the woofer. When calculating the port length can I just use the part of the port that will be touching the outer walls of the enclosure or is it really necessary to calculate the center line of the port.

I guess I am just not sure how exact every dimension needs to be. For example: you said I need a 4.5 cubic feet of internal volume. How exact will that have to be, if I am say with in 0.5% of that will I be fine or do I have to hit it exact?

Thanks

Jeff

5 percent error is acceptable on the internal volume. Heck, the T/S numbers you have are probably 10-15 percent off from the actual drivers you have.

For the port, calculate length as a line drawn through center of the port - as a line drawn through from start to end. You just need to use the internal volume and port dimensions I gave above for ideal performance (assuming your T/S spec are correct).

It's fine to use the avaserfi Kappa Perfect box as a model. Yours will be a little bit bigger of course, and with a slightly different port size and length, so you can't actually use that Kappa Perfect plan or it's cut list.

-Chris

 

[Jeff R.]

Thanks Chris - I will be starting in the next week or so.

 

[WmAx]

Thanks Chris - I will be starting in the next week or so.

After you draw up box plans, send them to me (PM me) and I'll check them over to make sure they are correct, if you so desire.

-Chris

 

[Jeff R.]

I am planning to the box out of the Birch Plywood as you mentioned Chris. I went the lumber yard today and I asked the salesman about 13 ply and he only had 3/4" Birch Plywood. Is this the same? He stated that he believed it was the same and ideal for any type of wood working application, escpecially to build a furniture quality box and stain it with poly.

Will this work fine?

 

[WmAx]

I am planning to the box out of the Birch Plywood as you mentioned Chris. I went the lumber yard today and I asked the salesman about 13 ply and he only had 3/4" Birch Plywood. Is this the same? He stated that he believed it was the same and ideal for any type of wood working application, escpecially to build a furniture quality box and stain it with poly.

Will this work fine?

Count the layers. It should have 13 layers, thus the '13 ply' specification.

-Chris

 

[Jeff R.]

I am still on the fence with the amp purchase. I really don't think that I will be needing a second sub for my application. If I decide to build another, it may be for another room in the house and then I have an over powered Behringer that I really only need half the power on. What do you think about buying the something smaller that will only have the power for the single box now and then if I decide to use a second I can just mirror the same amp for the second sub.

 

[WmAx]

I am still on the fence with the amp purchase. I really don't think that I will be needing a second sub for my application. If I decide to build another, it may be for another room in the house and then I have an over powered Behringer that I really only need half the power on. What do you think about buying the something smaller that will only have the power for the single box now and then if I decide to use a second I can just mirror the same amp for the second sub.

A plate amp that is 'half' the power of the Behringer EP2500 will cost at least as much, and probably more, than the Ep2500. On top of that, the plate amp will have inferior build and parts quality, and will not likely even produce 'half' the power. That is, a '1000 watt' plate amp may only produce 600-700 watts continuous. Moving down the power scale, the O Audio 500 Watt plate amp is the only plate amp I currently recommend. It is superior in quality and performance to most plate amps. It costs $230 plus shipping. It is closer to spec than most plate amps - it produces an actual 430 watts continuous. As comparison, the Dayton '1000 Watt' amp produces an actual 580 watts continuous. Be aware, the Ep2500 can be had for $280-$300 including shipping if you are a thrifty shopper. So, for just a tiny bit more than a 500 watt plate amp, you get a true 2000 watt amp with incredible build quality in the form of the EP2500. Note: I do generally presume that one will use a subsonic filter. The EP2500 has one that you can enable with a switch on the back, but it's at 25Hz I believe. I little high for HT use. So you would need to use an external one. The Art Clean Box would be ideal, actually. It both converts the consumer low voltage RCA signal from your receiver to pro level XLR outputs and it has a built in subsonic filter of sorts(though it is not intended - it is a design flaw - but it still works as a subsonic filter none the less).

-Chris

 

[annunaki]

I received my EP2500 for $260 shipped from www.zzounds.com on a price match from Amazon.

A $30.00 difference in price resulted in an additional 1,600 watts or so. It is worth every penny.

 

[Jeff R.]

Cold feet on this project......

I am just not ready to jump into the EP2500. I think it is a little more than I want to get into right now, it seems that everyone I see on this forum running something like this has many more resources on hand to dial this thing in and additional high end crossover networks, not to mention it will be sitting on my rack and will not look like if fits in with everything as nicely, yes I know asthetics should not matter but unfortunately they do in this case. I have two options I am considering. So as of now the Behringer is out, these are the two options I am considering.

First option is to keep my twin 10" Eclipses in the box I currently have (0.85 cu Ft sealed for each sub) wire the two 10"s to run a 4 ohm load and purchase an OAudio 500 plate amp to run them. I realize I will not get as much low end response and if it does not make me happy, all I have invested is the $229 for the amp which can always be used in a different application later. Seems like a relatively low risk. This will give me about the same if not lower bass in my system than I am currently running, not to mention 2 high quality 10" subs running at 500W. Like I mentioned earlier I have been running a 100W old 12" infinity. I have to believe this is a large upgrade for a minimal price.

Second Option is in an entirely different direction. I would purchase a new 7 channel amp from Emotiva, http://emotiva.com/upa7.shtm. I would use the 5 channels to run my 5 channel system and run the other two channels to power my sub. I could build the box that you recommended and run each extra channel to each independent voice coil. Thus I would be generating at 4 Ohms 185W RMS to each coil. or almost 400W RMS to the sub. My reciever should be able to cross over to the amp and handle gain, I believe.

What do you think?

Jeff

 

[WmAx]

Cold feet on this project......

I am just not ready to jump into the EP2500. I think it is a little more than I want to get into right now, it seems that everyone I see on this forum running something like this has many more resources on hand to dial this thing in and additional high end crossover networks, not to mention it will be sitting on my rack and will not look like if fits in with everything as nicely, yes I know asthetics should not matter but unfortunately they do in this case. I have two options I am considering. So as of now the Behringer is out, these are the two options I am considering.

First option is to keep my twin 10" Eclipses in the box I currently have (0.85 cu Ft sealed for each sub) wire the two 10"s to run a 4 ohm load and purchase an OAudio 500 plate amp to run them. I realize I will not get as much low end response and if it does not make me happy, all I have invested is the $229 for the amp which can always be used in a different application later. Seems like a relatively low risk. This will give me about the same if not lower bass in my system than I am currently running, not to mention 2 high quality 10" subs running at 500W. Like I mentioned earlier I have been running a 100W old 12" infinity. I have to believe this is a large upgrade for a minimal price.

Second Option is in an entirely different direction. I would purchase a new 7 channel amp from Emotiva, http://emotiva.com/upa7.shtm. I would use the 5 channels to run my 5 channel system and run the other two channels to power my sub. I could build the box that you recommended and run each extra channel to each independent voice coil. Thus I would be generating at 4 Ohms 185W RMS to each coil. or almost 400W RMS to the sub. My reciever should be able to cross over to the amp and handle gain, I believe.

What do you think?

Jeff

Just build a cabinet for each of the two 10" subs according to the box parameters I provided you. Use an O Audio 500 W for each one. You will have to run each sub at 8 ohms of course, and this will reduce the power form the amp to like 300 watts. But with two of these subs running, you will still get plenty of super clean LF output using the cabinets I specified.

If you use those 0.85" sealed cabinets the results will be rather sad in the house. My cabinet recommendations will likely yield around 4x the low bass output in comparison.

-Chris