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First DIY - Would this sub cabinet work OK?

post #1 of 59
Thread Starter 
I have two Dayton 18 HOs on order that I plan to put in separate sealed boxes and power with an ep4000 I just bought. I've been planning to buy a couple flat packs from Erich but not sure when they'll be available and just found some on PE that I'm wondering about. I'm sure it's inferior quality birch but looks like 6 ply 3/4" which I think some of you have used successfully.

http://www.parts-express.com/pe/showdetl.cfm?partnumber=245-328

I'd like to get started soon so if these should be sufficient, I might consider them.

My other concern is these are 5.75 cuft internal so not sure how they'd model as that's larger than the #'s I've seen thrown around on here... I assume that would be fine though.

What do you all think? OK with these PE boxes or hold off and hope I can get some from Erich soon?

Sent from my Nexus 7 using Tapatalk HD
post #2 of 59
The cabinet should work fine, but it seems like the wood quality of these boxes based on the reviews is poor. If you do buy them, you would want to use bondo or something similar to fill all the voids and I would not plan on staining them since it appears to be cheap Asian wood with a thin veneer.
post #3 of 59
Well you could always add some internal braces to take up some airspace. At that size I wouldn't go over 500 watts. Win ISD shows it passing max excursion with 500 watts at around 10hz. In comparison, a 3.5cf cab with 850 watts will yield upwards of another 3db in the upper frequencies for more midbass punch. Not a huge deal, but the smaller cab would allow for a power upgrade down the road without bottoming the driver.
post #4 of 59
I think you'll be fine with that cabinet. Exceeding 20mm below 10hz might cause some strain in an extreme situation, but you arent in danger of damaging the driver. The larger cabinet does gain you free efficiency down low, the F10 is 20hz.

I say go for it.
post #5 of 59
Thread Starter 
Thanks for the feedback. I think drop Erich a pm today... If it could be a while, I'll probably pull the trigger on this PE one.

Good idea about adding some braces... will probably do that.

Thinking I'll finish with Duratex so hopefully it helps conceal any small imperfections in the birch. Would you suggest PL Premium for glue?

Last question - should I be concerned with the single front baffle? Aside from not being able to flush mount the driver, any downsides? I'll build some grills so can live without the double baffle if the benefit is mostly cosmetic.

Sounds like I might even be able to use my ep4000 to power a couple more subs this size down the road if I only need to push 500 watts to each. I assume I can somehow wire the ep4k to push that amount?

Sent from my Galaxy Nexus using Tapatalk 2
post #6 of 59
Not a bad choice if you're got limited tools and don't want to wait for Erich's DIY flat pack. The volume is a bit on the large side, but with the ~650 watts from the EP4000 you should be OK. For the price though Erich's flatpack would definitely be a better option.

As for your other questions:

Single baffle - I would for sure do some bracing (can use dowels) to connect the front/rear together just to be safe. This should reduce the chance of panel vibrations normally reduced by the extra mass of the added baffle.

Duratex does go on thick and should cover (visually) most of the voids. You can use Titebond or even PL premium to hold the box together.
post #7 of 59
If anything the PE box is a bit small for a sealed 18" sub. There's no benefit to a smaller box other than space savings, all it does is eat up power that would otherwise be converted into bass. Seal it up and reinforce it and you're in business.
Quote:
Originally Posted by benunc View Post

I have two Dayton 18 HOs on order that I plan to put in separate sealed boxes and power with an ep4000 I just bought. I've been planning to buy a couple flat packs from Erich but not sure when they'll be available and just found some on PE that I'm wondering about. I'm sure it's inferior quality birch but looks like 6 ply 3/4" which I think some of you have used successfully.

http://www.parts-express.com/pe/showdetl.cfm?partnumber=245-328

I'd like to get started soon so if these should be sufficient, I might consider them.

My other concern is these are 5.75 cuft internal so not sure how they'd model as that's larger than the #'s I've seen thrown around on here... I assume that would be fine though.

What do you all think? OK with these PE boxes or hold off and hope I can get some from Erich soon?

Sent from my Nexus 7 using Tapatalk HD
post #8 of 59
Quote:
Originally Posted by imagic View Post

If anything the PE box is a bit small for a sealed 18" sub. There's no benefit to a smaller box other than space savings, all it does is eat up power that would otherwise be converted into bass. Seal it up and reinforce it and you're in business.

The benefit with this driver is excursion control. This driver tends to perform best in a balance of power handling / efficiency in a 4.5 cubed box or so. It is designed for optimum use in relatively small enclosures. Any larger and you have to start watching power/excursion.
post #9 of 59
I understand that approach. It's nice to know that it is a highly competent driver when mounted small/sealed - I bet some folks will use them in their car. For HT use, I don't see what's so optimum about shrinking a box until a driver consumes all the power an amp puts out, especially if the builder is using DSP.

What I see when I model the Dayton in WinISD is that a 10 cubic foot enclosure gains 2db at 20hz and 3db below 20hz, while only losing 1db above 40hz... as compared to a 4.5 cubic foot box. The differences between 4.5 and 5.75 cubic feet are so small, they are almost meaningless (under 1db across the whole range).

I'm going to agree with Jay1 on this:
Quote:
Originally Posted by Jay1 View Post

I think you'll be fine with that cabinet. Exceeding 20mm below 10hz might cause some strain in an extreme situation, but you arent in danger of damaging the driver. The larger cabinet does gain you free efficiency down low, the F10 is 20hz.
I say go for it.
Quote:
Originally Posted by Gorilla83 View Post

The benefit with this driver is excursion control. This driver tends to perform best in a balance of power handling / efficiency in a 4.5 cubed box or so. It is designed for optimum use in relatively small enclosures. Any larger and you have to start watching power/excursion.

Edited by imagic - 1/16/13 at 1:54pm
post #10 of 59
Quote:
Originally Posted by imagic View Post


What I see when I model the Dayton in WinISD is that a 10 cubic foot enclosure gains 2db at 20hz and 3db below 20hz, while only losing 1db above 40hz... as compared to a 4.5 cubic foot box. The differences between 4.5 and 5.75 cubic feet are so small, they are almost meaningless (under 1db across the whole range).

I get a completely different response. First off, 10 cubic feet is way, way to large. I'd rather go by actual builds that have been successful (Gorillas, etc) than rely on Win Isd any day. Secondly, I show you gaining a whopping 2 db's under 15hz and losing almost 3db's over 50. Now factor in that you are well over the excursion safety threshold by the time you get into the mid teens, and you've counteracted any gain in that range anyways. So a cab that big has given up all useable output compared to the smaller one.
post #11 of 59
Sealed boxes are remarkably predictable. Trusting WinISD and similar programs is tricky for ported builds but the math behind a sealed sub is so straight-forward that the models will work so long as the T/S parameters are reliable.
Quote:
"Now factor in that you are well over the excursion safety threshold by the time you get into the mid teens"
- Wasting all the power an amp can put out so you can hit the max power rating for the driver without hitting the over-excursion point? That's an SPL drag and has nothing to do with listening to music/movies. Who's buying high-excursion 18" subwoofers specifically for their efficiency above 50hz? Upgrade your mains!

Small sealed is popular now, enabled by cheap amplification... but at some point I wonder why anyone's goal would be to max out their amp and their sub by shrinking the box unless space comes at a premium.
Quote:
Originally Posted by bass addict View Post

I get a completely different response. First off, 10 cubic feet is way, way to large. I'd rather go by actual builds that have been successful (Gorillas, etc) than rely on Win Isd any day. Secondly, I show you gaining a whopping 2 db's under 15hz and losing almost 3db's over 50. Now factor in that you are well over the excursion safety threshold by the time you get into the mid teens, and you've counteracted any gain in that range anyways. So a cab that big has given up all useable output compared to the smaller one.

Edited by imagic - 1/16/13 at 9:37am
post #12 of 59
Quote:
Originally Posted by benunc View Post


My other concern is these are 5.75 cuft internal so not sure how they'd model as that's larger than the #'s I've seen thrown around on here... I assume that would be fine though.
The driver is going to take up some volume, as will braces, which should not be considered optional. The maximum displacement limited output between 3 and 6 cu ft has less than a 1dB spread, so it's not something to be concerned about.
post #13 of 59
The difference in SPL (maximum) is marginal (as Bill noted above) between lets say 3.5 cubes and 5.75 cubes, but the difference in excursion is huge. yes, the larger box will be a bit more efficient, but in my case I'm not willing to potentially compromise the driver for that benefit. Both modeled with 650W using Josh Ricci's measured parameters:

With the EP4000's power this really isn't an issue for this situation, but apply something like the CV5000, clone, etc. and you will have to apply a HPF.

post #14 of 59
Quote:
Originally Posted by Gorilla83 View Post

The difference in SPL (maximum) is marginal (as Bill noted above) between lets say 3.5 cubes and 5.75 cubes, but the difference in excursion is huge.
There's no particular advantage to going with a smaller box to limit excursion. You don't get somethin' for nothin', and what you don't get when you limit excursion is output. That's why looking at the excursion chart in and of itself doesn't tell the entire picture, nor does looking at the SPL chart. Maximum SPL is the most useful chart, as it considers both thermal and displacement limits as well as sensitivity to paint a complete picture of what you'll get out of a given box size. Where the excursion chart does come in handy is determining how you should limit and high pass the cab if you're trying to get the most out of it, but that's generally a pro-sound concern.
post #15 of 59
Quote:
Originally Posted by Bill Fitzmaurice View Post

There's no particular advantage to going with a smaller box to limit excursion. You don't get somethin' for nothin', and what you don't get when you limit excursion is output. That's why looking at the excursion chart in and of itself doesn't tell the entire picture, nor does looking at the SPL chart. Maximum SPL is the most useful chart, as it considers both thermal and displacement limits as well as sensitivity to paint a complete picture of what you'll get out of a given box size. Where the excursion chart does come in handy is determining how you should limit and high pass the cab if you're trying to get the most out of it, but that's generally a pro-sound concern.

When looking at maximum SPL for boxes comparing 3.5 cubes to 6 cubes, the difference is pretty much meaningless. If you're willing to throw a bit of extra power at the expense of space, I can't see the advantage of building a huge box unless you're power limited?
post #16 of 59
I'm not seeing that difference in excursion as being 'huge' SI claims 45mm one-way XMech. The driver is safe either way.

I thought bass output is directly correlated to the piston movement of the driver when in a sealed system, so at any given excursion a driver will produce the same SPL with the amount of power needed to overcome the 'air spring' being the only real variable.
Quote:
Originally Posted by Gorilla83 View Post

The difference in SPL (maximum) is marginal (as Bill noted above) between lets say 3.5 cubes and 5.75 cubes, but the difference in excursion is huge. yes, the larger box will be a bit more efficient, but in my case I'm not willing to potentially compromise the driver for that benefit. Both modeled with 650W using Josh Ricci's measured parameters:

With the EP4000's power this really isn't an issue for this situation, but apply something like the CV5000, clone, etc. and you will have to apply a HPF.


All we're talking about here is 20x20x20 vs. 24x24x24
Quote:
Originally Posted by Gorilla83 View Post

When looking at maximum SPL for boxes comparing 3.5 cubes to 6 cubes, the difference is pretty much meaningless. If you're willing to throw a bit of extra power at the expense of space, I can't see the advantage of building a huge box unless you're power limited?
post #17 of 59
The driver being discussed here, the Dayton 18, has usable excursion of around 20-22mm as measured by Josh Ricci. Xmech is a bit further than that, but really no need to take it to that point if you're not gaining anything.

Anyway, like I stated earlier with the EP4000 the OP would be safe with that box if he chose to do so. Back on track.cool.gif
post #18 of 59
Not even sure what happened there. I must be going senile, confusing the SI with the Dayton. Jolly good. The one thing I still want to know - how does the Dayton handle over-excursion, does it crash or just fade away?
Quote:
Originally Posted by Gorilla83 View Post

The driver being discussed here, the Dayton 18, has usable excursion of around 20-22mm as measured by Josh Ricci. Xmech is a bit further than that, but really no need to take it to that point if you're not gaining anything.

Anyway, like I stated earlier with the EP4000 the OP would be safe with that box if he chose to do so. Back on track.cool.gif

As for what advantage a larger box could provide... lower heat-related THD when pushing at lower frequencies, and also less stress on the amp and the power line to achieve the same SPL. Some people care about wasting electricity.

Bill said it better than I:
Quote:
Originally Posted by Bill Fitzmaurice View Post

There's no particular advantage to going with a smaller box to limit excursion. You don't get somethin' for nothin', and what you don't get when you limit excursion is output. That's why looking at the excursion chart in and of itself doesn't tell the entire picture, nor does looking at the SPL chart. Maximum SPL is the most useful chart, as it considers both thermal and displacement limits as well as sensitivity to paint a complete picture of what you'll get out of a given box size. Where the excursion chart does come in handy is determining how you should limit and high pass the cab if you're trying to get the most out of it, but that's generally a pro-sound concern.

Edited by imagic - 1/16/13 at 11:57am
post #19 of 59
I would recommend filling the voids with some simple drywall spackle before applying the Duratex. It won't take long at all, just fill in the voids, let the spackle dry, and then sand and wipe off the dust before you apply the Duratex. I modeled this in Winisd Pro in a sealed box using the parameters above (2 boxes, 2 Dayton drivers) EP 4000 powering them, and I think you will have some nice output and extension. How large is your room, and what sub/subs do you have now?
post #20 of 59
Thread Starter 
I appreciate all the feedback. Sounds like I should be OK using the PE boxes as long as I don't push the subs too hard. I never listen at reference levels so don't expect to reach 120+ dbs so hopefully I won't risk damaging the drivers.

The one power tool I have is a miter saw so it will be easy for me to add some bracing which I'll definitely do; thanks for suggestion.

Separate question - Do you guys recommend the Acousta-Stuf Polyfill that PE sells? Or can I get by with something cheaper like pillow stuffing and/or roxul scraps I have from some acoustic panels I've made? According to PE, I'd need 5 lbs of polyfill which would cost $55.... seems expensive.
post #21 of 59
Pillows from Wal-Mart work just as well, cost quite a bit less when on sale.
Quote:
Originally Posted by benunc View Post

I appreciate all the feedback. Sounds like I should be OK using the PE boxes as long as I don't push the subs too hard. I never listen at reference levels so don't expect to reach 120+ dbs so hopefully I won't risk damaging the drivers.

The one power tool I have is a miter saw so it will be easy for me to add some bracing which I'll definitely do; thanks for suggestion.

Separate question - Do you guys recommend the Acousta-Stuf Polyfill that PE sells? Or can I get by with something cheaper like pillow stuffing and/or roxul scraps I have from some acoustic panels I've made? According to PE, I'd need 5 lbs of polyfill which would cost $55.... seems expensive.
post #22 of 59
Thread Starter 
Quote:
Originally Posted by ack_bk View Post

I would recommend filling the voids with some simple drywall spackle before applying the Duratex. It won't take long at all, just fill in the voids, let the spackle dry, and then sand and wipe off the dust before you apply the Duratex. I modeled this in Winisd Pro in a sealed box using the parameters above (2 boxes, 2 Dayton drivers) EP 4000 powering them, and I think you will have some nice output and extension. How large is your room, and what sub/subs do you have now?

I know I have some spackle laying around somewhere so will definitely do that; thanks.

Room is almost 3,700 cu ft - bonus room sealed off from rest of house. I currently have 1 Epik Empire and 1 Epik Legend. I'm going to try running all 4 subs together; probably 2 nearfield and two near mains, flanking screen. I have REW and a calibrated mic so can play around with everything to try to get a setup that gets me a good response. Per someone's suggestion in another thread, I might experiment with using a HPF on 1-2 of the Epiks; could something like this FMOD from PE work for that purpose?
post #23 of 59
Thread Starter 
Quote:
Originally Posted by imagic View Post

Pillows from Wal-Mart work just as well, cost quite a bit less when on sale.

Perfect, that's what I was hoping to hear.
post #24 of 59
Quote:
Originally Posted by benunc View Post

I appreciate all the feedback. Sounds like I should be OK using the PE boxes as long as I don't push the subs too hard. I never listen at reference levels so don't expect to reach 120+ dbs so hopefully I won't risk damaging the drivers.

The one power tool I have is a miter saw so it will be easy for me to add some bracing which I'll definitely do; thanks for suggestion.

Separate question - Do you guys recommend the Acousta-Stuf Polyfill that PE sells? Or can I get by with something cheaper like pillow stuffing and/or roxul scraps I have from some acoustic panels I've made? According to PE, I'd need 5 lbs of polyfill which would cost $55.... seems expensive.

I went to Michaels crafts and got stuffing from there. It was 4 or 5 bucks a bag and can be teased nice and fluffy (its a little firm out of the package). I've used it in a bunch of sub and speaker builds and it does just great. I think I spent like 15 bucks and still have leftovers after a couple smaller projects.

Scott
post #25 of 59
Quote:
Originally Posted by benunc View Post

I know I have some spackle laying around somewhere so will definitely do that; thanks.

Room is almost 3,700 cu ft - bonus room sealed off from rest of house. I currently have 1 Epik Empire and 1 Epik Legend. I'm going to try running all 4 subs together; probably 2 nearfield and two near mains, flanking screen. I have REW and a calibrated mic so can play around with everything to try to get a setup that gets me a good response. Per someone's suggestion in another thread, I might experiment with using a HPF on 1-2 of the Epiks; could something like this FMOD from PE work for that purpose?

Those FMOD's seem like they would work, but I would defer to the more knowedgeable folks here smile.gif Another option would be to use something like a minidsp, but that will cost more $$.

REW and the calibrated mic will really help. I suspect with a pair of these bad boys, you may not need the Legend or the Empire anymore smile.gif But that is the fun in being able to go DIY and measure your room and response.

Seems like a cool project, let us know how things progress.
post #26 of 59
Quote:
Originally Posted by skeeter99 View Post

I went to Michaels crafts and got stuffing from there. It was 4 or 5 bucks a bag and can be teased nice and fluffy (its a little firm out of the package). I've used it in a bunch of sub and speaker builds and it does just great. I think I spent like 15 bucks and still have leftovers after a couple smaller projects.

Scott

I just bout 14 pounds of Polyfill from Walmart, I want to say it was just under $30.
post #27 of 59
Quote:
Originally Posted by skeeter99 View Post

It was 4 or 5 bucks a bag and can be teased nice and fluffy

Ummm, we're still talking about speakers right? biggrin.gif
post #28 of 59
Quote:
Originally Posted by ack_bk View Post

I just bout 14 pounds of Polyfill from Walmart, I want to say it was just under $30.

Nice! That's a good price and I'm sure it'll work well for your needs.

Scott
post #29 of 59
Quote:
Originally Posted by bass addict View Post

Ummm, we're still talking about speakers right? biggrin.gif

Haha! Yup!
post #30 of 59
Quote:
Originally Posted by Gorilla83 View Post

I can't see the advantage of building a huge box unless you're power limited?
Neither can I, which is another reason to give the maximum SPL chart the highest priority. It will tell you if you're getting anything useful or just wasting wood.
Quote:
I might experiment with using a HPF on 1-2 of the Epiks; could something like this FMOD from PE work for that purpose?
Like all passive filters the corner frequency depends on the load impedance, in this case that's the input impedance of the amp. As that could vary by a few hundred thousand ohms between different amps the FMod is pretty useless, especially with only a 2nd order slope.
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