Please help with designing a box for this amp and these woofers ( :

[TucsonAZ]

I used to be really into audio 3 decades ago but back then there weren't a ton of resources and we were all just king of winging it. Now, there's a lot to learn and and it's giving me information paralysis. All I want to do is build a simple home theater sub so if somebody could help me with the box design I would be thankful. Here's my main focus:

1) Sound quality first.
2) Multi-functional, I'm going to build it as a coffee table or end table.
3) Down firing ideally to protect the speaker.

It will be paired with a set of KRK Rokit 8s and those cover roughly 45hz-20mhz so I need it just for the very lows.

I don't know a think about tuning or anything else but I am a hobby woodworker with all of the tools so I'm fine with a more complicated design. I just need somebody to spell it our for me as I don't understand the basics of tuning a box (I have way too many hobbies).

I have the Dayton SPA250DSP plate amp as seen here:

Dayton Audio SPA250DSP 250W Subwoofer Plate Amplifier with DSP

Dayton Audio SPA250DSP 250W Subwoofer Plate Amplifier with DSPDayton Audio SPA250DSP Subwoofer Plate AmplifierElite Control with DSPDayton Audio's SPA250DSP true 250 watt digital switching plate amplifier features advanced signal processing control that every audio enthusiast wants. With Class D...

www.parts-express.com

I also have 4 of the Goldwood GW-15PC-8 15" as seen here:

Goldwood GW-15PC-8 15" Heavy Duty Woofer 8 Ohm

Goldwood GW-15PC-8 15" Heavy Duty Woofer 8 OhmThe Heavy Duty PC Series is available in 4 ohm and 8 ohm versions for wiring flexibility making these perfect replacement drivers for many home audio applications. The woofers handle the most powerful of amplifiers while maintaining sonic excellence...

www.parts-express.com

With the woofers, I ended up getting them for a really good price buying 4 and I know I will need at least 2 in the build to get them to 4ohms for the amp. As such I was thinking an isobaric design but I know those have fallen out of favor.

I'm sure there's a lot I'm missing so don't feel bad telling me if I'm completely off on anything. I don't need to get silly loud I just want to add more texture to what I currently have as the KRKs are amazing (I have the Rokit 5s as my computer speakers) but they of course lack lows.

 

[isolar8001]

I used to be really into audio 3 decades ago but back then there weren't a ton of resources and we were all just king of winging it. Now, there's a lot to learn and and it's giving me information paralysis. All I want to do is build a simple home theater sub so if somebody could help me with the box design I would be thankful. Here's my main focus:

1) Sound quality first.
2) Multi-functional, I'm going to build it as a coffee table or end table.
3) Down firing ideally to protect the speaker.

It will be paired with a set of KRK Rokit 8s and those cover roughly 45hz-20mhz so I need it just for the very lows.

I don't know a think about tuning or anything else but I am a hobby woodworker with all of the tools so I'm fine with a more complicated design. I just need somebody to spell it our for me as I don't understand the basics of tuning a box (I have way too many hobbies).

I have the Dayton SPA250DSP plate amp as seen here:

Dayton Audio SPA250DSP 250W Subwoofer Plate Amplifier with DSP

Dayton Audio SPA250DSP 250W Subwoofer Plate Amplifier with DSPDayton Audio SPA250DSP Subwoofer Plate AmplifierElite Control with DSPDayton Audio's SPA250DSP true 250 watt digital switching plate amplifier features advanced signal processing control that every audio enthusiast wants. With Class D...

www.parts-express.com

I also have 4 of the Goldwood GW-15PC-8 15" as seen here:

Goldwood GW-15PC-8 15" Heavy Duty Woofer 8 Ohm

Goldwood GW-15PC-8 15" Heavy Duty Woofer 8 OhmThe Heavy Duty PC Series is available in 4 ohm and 8 ohm versions for wiring flexibility making these perfect replacement drivers for many home audio applications. The woofers handle the most powerful of amplifiers while maintaining sonic excellence...

www.parts-express.com

With the woofers, I ended up getting them for a really good price buying 4 and I know I will need at least 2 in the build to get them to 4ohms for the amp. As such I was thinking an isobaric design but I know those have fallen out of favor.

I'm sure there's a lot I'm missing so don't feel bad telling me if I'm completely off on anything. I don't need to get silly loud I just want to add more texture to what I currently have as the KRKs are amazing (I have the Rokit 5s as my computer speakers) but they of course lack lows.

First off....anyway you can return what you have bought from Parts Express ?

You are pretty much going about this totally wrong.
You bought 4 generic woofers that are better suited to be replacements in ancient full range speakers of the Fisher/Cerwin Vega genre...they will make for very poor subwoofers, even using two/four of them.

For what you have spent, you could buy a real subwoofer without having to use 4 generic woofers and a generic amp.

Anyhow, more info on the total system would be helpful.

 

[TucsonAZ]

First off....anyway you can return what you have bought from Parts Express ?

You are pretty much going about this totally wrong.
You bought 4 generic woofers that are better suited to be replacements in ancient full range speakers of the Fisher/Cerwin Vega genre...they will make for very poor subwoofers, even using two/four of them.

For what you have spent, you could buy a real subwoofer without having to use 4 generic woofers and a generic amp.

Anyhow, more info on the total system would be helpful.

Well, so far with the amp and two of the speakers I'm out $240 all in. Other than the KRKs there is nothing else, just them and this sub I'm trying to build to add to them. I'm of course open to something, anything else really but then I would need suggestions on what would serve me better for under $250 and I feel like from the looking I've done there isn't much. I'm also just trying to keep things extra simple. I got that amp as I wanted XLR connections to easily work with the KRKs.

Thanks for the reply.

 

[highfigh]

Well, so far with the amp and two of the speakers I'm out $240 all in. Other than the KRKs there is nothing else, just them and this sub I'm trying to build to add to them. I'm of course open to something, anything else really but then I would need suggestions on what would serve me better for under $250 and I feel like from the looking I've done there isn't much. I'm also just trying to keep things extra simple. I got that amp as I wanted XLR connections to easily work with the KRKs.

Thanks for the reply.

OK, so the Dayton sub amp and KRK speakers have XLR inputs- what source are you using to send the audio to the sub/speakers?

 

[TLS Guy]

I used to be really into audio 3 decades ago but back then there weren't a ton of resources and we were all just king of winging it. Now, there's a lot to learn and and it's giving me information paralysis. All I want to do is build a simple home theater sub so if somebody could help me with the box design I would be thankful. Here's my main focus:

1) Sound quality first.
2) Multi-functional, I'm going to build it as a coffee table or end table.
3) Down firing ideally to protect the speaker.

It will be paired with a set of KRK Rokit 8s and those cover roughly 45hz-20mhz so I need it just for the very lows.

I don't know a think about tuning or anything else but I am a hobby woodworker with all of the tools so I'm fine with a more complicated design. I just need somebody to spell it our for me as I don't understand the basics of tuning a box (I have way too many hobbies).

I have the Dayton SPA250DSP plate amp as seen here:

Dayton Audio SPA250DSP 250W Subwoofer Plate Amplifier with DSP

Dayton Audio SPA250DSP 250W Subwoofer Plate Amplifier with DSPDayton Audio SPA250DSP Subwoofer Plate AmplifierElite Control with DSPDayton Audio's SPA250DSP true 250 watt digital switching plate amplifier features advanced signal processing control that every audio enthusiast wants. With Class D...

www.parts-express.com

I also have 4 of the Goldwood GW-15PC-8 15" as seen here:

Goldwood GW-15PC-8 15" Heavy Duty Woofer 8 Ohm

Goldwood GW-15PC-8 15" Heavy Duty Woofer 8 OhmThe Heavy Duty PC Series is available in 4 ohm and 8 ohm versions for wiring flexibility making these perfect replacement drivers for many home audio applications. The woofers handle the most powerful of amplifiers while maintaining sonic excellence...

www.parts-express.com

With the woofers, I ended up getting them for a really good price buying 4 and I know I will need at least 2 in the build to get them to 4ohms for the amp. As such I was thinking an isobaric design but I know those have fallen out of favor.

I'm sure there's a lot I'm missing so don't feel bad telling me if I'm completely off on anything. I don't need to get silly loud I just want to add more texture to what I currently have as the KRKs are amazing (I have the Rokit 5s as my computer speakers) but they of course lack lows.

You can not build sub with those drivers, the Thiele/Small parameters are not suitable.

So without different drivers your project is a non starter.

 

[TLS Guy]

I used to be really into audio 3 decades ago but back then there weren't a ton of resources and we were all just king of winging it. Now, there's a lot to learn and and it's giving me information paralysis. All I want to do is build a simple home theater sub so if somebody could help me with the box design I would be thankful. Here's my main focus:

1) Sound quality first.
2) Multi-functional, I'm going to build it as a coffee table or end table.
3) Down firing ideally to protect the speaker.

It will be paired with a set of KRK Rokit 8s and those cover roughly 45hz-20mhz so I need it just for the very lows.

I don't know a think about tuning or anything else but I am a hobby woodworker with all of the tools so I'm fine with a more complicated design. I just need somebody to spell it our for me as I don't understand the basics of tuning a box (I have way too many hobbies).

I have the Dayton SPA250DSP plate amp as seen here:

Dayton Audio SPA250DSP 250W Subwoofer Plate Amplifier with DSP

Dayton Audio SPA250DSP 250W Subwoofer Plate Amplifier with DSPDayton Audio SPA250DSP Subwoofer Plate AmplifierElite Control with DSPDayton Audio's SPA250DSP true 250 watt digital switching plate amplifier features advanced signal processing control that every audio enthusiast wants. With Class D...

www.parts-express.com

I also have 4 of the Goldwood GW-15PC-8 15" as seen here:

Goldwood GW-15PC-8 15" Heavy Duty Woofer 8 Ohm

Goldwood GW-15PC-8 15" Heavy Duty Woofer 8 OhmThe Heavy Duty PC Series is available in 4 ohm and 8 ohm versions for wiring flexibility making these perfect replacement drivers for many home audio applications. The woofers handle the most powerful of amplifiers while maintaining sonic excellence...

www.parts-express.com

With the woofers, I ended up getting them for a really good price buying 4 and I know I will need at least 2 in the build to get them to 4ohms for the amp. As such I was thinking an isobaric design but I know those have fallen out of favor.

I'm sure there's a lot I'm missing so don't feel bad telling me if I'm completely off on anything. I don't need to get silly loud I just want to add more texture to what I currently have as the KRKs are amazing (I have the Rokit 5s as my computer speakers) but they of course lack lows.

I have a number of DIY sub designs of mine on file. Some have been built by members with good results.

DIY sub builds are very feasible, but the design has to be correct, otherwise it is a total waste of time and money. So if you are serious about building a good sub I can help you. However I have zero interest in helping you waste time and money.

 

[TucsonAZ]

OK, so the Dayton sub amp and KRK speakers have XLR inputs- what source are you using to send the audio to the sub/speakers?

Likely just a dac from my computer.

 

[TucsonAZ]

I have a number of DIY sub designs of mine on file. Some have been built by members with good results.

DIY sub builds are very feasible, but the design has to be correct, otherwise it is a total waste of time and money. So if you are serious about building a good sub I can help you. However I have zero interest in helping you waste time and money.

Okay, I scrapped those speakers and canceled the order with them so I'm starting with just the amp. I do really like this one:

Amazon.com

Mostly because it's over the top absurd though. I'm honestly open to anything, just trying to find the best value for the money, whatever that point of diminishing returns is.

 

[highfigh]

Likely just a dac from my computer.

You don't need XLR.

 

[TucsonAZ]

You don't need XLR.

Computer to plate amp XLR and then plate amp XLR to XLRs on the back of the KRKs.

 

[Tankini]

Okay, I scrapped those speakers and canceled the order with them so I'm starting with just the amp. I do really like this one:

Amazon.com

Mostly because it's over the top absurd though. I'm honestly open to anything, just trying to find the best value for the money, whatever that point of diminishing returns is.

@TucsonAZ TLS Guy gave you his thoughts on your audio project. Why even post up a link to another website directed at TLS Guy. Don't you have a thread over on AVSforum of this build your trying/thinking of doing. Every response that you have received told you, your going about it the wrong way. One even stated you don't need XLR cable/'s.

This:> quote: > "whatever the point of dimension return is" A rhetorical question is why, TSL Guy, out right refuses to take it any further with you. Mark will not click on that link or any other AH member, we on AH have seen links as such.

 

[TLS Guy]

Okay, I scrapped those speakers and canceled the order with them so I'm starting with just the amp. I do really like this one:

Amazon.com

Mostly because it's over the top absurd though. I'm honestly open to anything, just trying to find the best value for the money, whatever that point of diminishing returns is.

It is not over the top absurd, but groveling in the basement. That is a JUNK car sub. Worse it has no Thiele/Small parameters published, so it is IMPOSSIBLE to design a sub for that driver.

Car sub drivers are different to home sub drivers, and almost universally car sub drivers are no good in the home. You just ordered a junk driver and whatever you build will be junk.

If you want good results you are going to have to listen to people who actually know what they are doing. At the moment you have no clue and worse you don't know what you don't know.

 

[isolar8001]

Okay, I scrapped those speakers and canceled the order with them so I'm starting with just the amp. I do really like this one:

Amazon.com

Mostly because it's over the top absurd though. I'm honestly open to anything, just trying to find the best value for the money, whatever that point of diminishing returns is.

Everything TLSGuy is telling you is the gospel truth....heed his words !

What confuses me about this thread is the basic layout.
The KRK speakers you have are generally used as desktop speakers for a PC setup...any sub plugged into them would usually be in the same vicinity. (under the desk or on the sides)
.
But, then you speak of making a sub to use as a coffee table or end table....far away from the desktop.
Just what is the layout ? Where are the main speakers ? On a PC desk, or on each side of a TV ?

 

[Tankini]

First off....anyway you can return what you have bought from Parts Express ?

You are pretty much going about this totally wrong.
You bought 4 generic woofers that are better suited to be replacements in ancient full range speakers of the Fisher/Cerwin Vega genre...they will make for very poor subwoofers, even using two/four of them.

For what you have spent, you could buy a real subwoofer without having to use 4 generic woofers and a generic amp.

Anyhow, more info on the total system would be helpful.

Truth be told!

 

[BoredSysAdmin]

Here OP, this list of measured Sub and Sub drivers should give you some idea of what good subs look like:

Data-Bass: Subwoofer Measurements

data-bass.com

Also about TLSGuy, if you want top-notch help with subwoofer design, lower your head a bit, ask questions, and be happy with the responses. TLSGuy, aka Mark, has little patience for BS, but trust me—his help is invaluable if you're serious. At least I know the stuff I don't know. You aren't there yet

 

[highfigh]

Computer to plate amp XLR and then plate amp XLR to XLRs on the back of the KRKs.

Computer has XLR? I have never seen that.

I understood how the plate amp and XLR connect- been working with audio/pro audio since 1972 but it's not mandatory for the plate amp and KRKs, either.

 

[BoredSysAdmin]

Computer has XLR? I have never seen that.

I understood how the plate amp and XLR connect- been working with audio/pro audio since 1972 but it's not mandatory for the plate amp and KRKs, either.

Well, TECHNICALLY, one could have a PCI audio interface installed in a computer and have XLR interfaces.
For example This card and this cable. I also fully realize how scarce and niche such a card is and for all sake and purposes you're 100% correct - the vast majority of all computers do not have XLR ports.

 

[highfigh]

Well, TECHNICALLY, one could have a PCI audio interface installed in a computer and have XLR interfaces.
For example This card and this cable. I also fully realize how scarce and niche such a card is and for all sake and purposes you're 100% correct - the vast majority of all computers do not have XLR ports.

Desktop, sure, but they didn't say- only DAC.

I have a Tascam interface, so I'm familiar.

I want to see a MacBook with a pair of XLR- that ought to look pretty wild.

 

[TucsonAZ]

Everything TLSGuy is telling you is the gospel truth....heed his words !

What confuses me about this thread is the basic layout.
The KRK speakers you have are generally used as desktop speakers for a PC setup...any sub plugged into them would usually be in the same vicinity. (under the desk or on the sides)
.
But, then you speak of making a sub to use as a coffee table or end table....far away from the desktop.
Just what is the layout ? Where are the main speakers ? On a PC desk, or on each side of a TV ?

Here's how this started, I was running Optimus LX4 I got from Goodwill for $6, on my computer. They sounded amazing, I decided to to the Black Dahlia mod on them, they sounded even better. Eventually I wanted more so I went to the KRK Rokit 5s with a DragonFly DAC and it was even better.

I liked the KRKs enough I went with some Rokit 8s I found a deal on for my TV and music which is run by a second computer I have. DragonFly 2.5mm to XLR cables out to the KRK which are sitting on either side of a 60" television. I just wanted better lows and studio subs aren't super common and I figured I could build better than the KRK sub for the $500 it cost.

And now here we are, me totally out of my depths on how to make a subwoofer and happy to see just how nerdy things have gotten. Huge strides in speaker designing and DIY which is amazing.

I'm open to any subwoofer, I'm just trying to stay reasonable on the price. I'm fine with a 15" or two 12s if that's better, I would like to get down to 20hz for movies and so on. The only thing I'm set on is using the plate amp, I already have it and like the XLR connections.

Thank you all for the responses, ears wide open, happy to buy any sub that would work well with that amp and build any box that served them well.

 

[TLS Guy]

Here is a cost effective design using the Dayton RSS31HF

This will do just what you want at reasonable cost if you build it correctly and follow my design exactly.