Build Plans, 18" Dayton Slot Port

mikectm2

mikectm2

Audiophyte
I have thought about putting it all together in a single PDF one could download and have complete plans but so far I have not really seen the demand. I think it seems too complex for the average DIY sub builder seeking plans.
That'd be a good idea. I just tried downloading your .skp document ....and nothing on my iMac can open it. Was trying to print something out, that could show to my woodworker neighbor.

suggestions ?
 
Rob Harrison

Rob Harrison

Enthusiast
Haoleb,

With regards to lining up and drilling the mounting-bolt holes for the speaker... I always get nervous when it comes to this, and it sounds like I'll need to be extra careful on this one.

I've been using a set of self-centering drill bits for this kind of work, mounting hinges, etc. I think they are called Vix Bits. Guessing there are other manufacturers out there... you should be able to get them at rock ler or wood smith or jet, possibly the orange or red/blue box stores as well. Is MLCS around still???

Anyways, they work really well for centering drilled holes in things like hinges, drivers, etc.

Obviously, getting the holes absolutely perpendicular to the baffle face is important to make sure the bolts mate evenly across the speaker flange. My drill press is great for getting the holes perpindicular and I don't trust drilling absolutely perpendicular with my hand drill. I"ll need to drill the holes before I mount the baffle as I foresee me getting rather frustrated if I try to manhandle the box onto my drill press table.

Planning this out... I think I'll do this:

1. Laminate the baffle and route it.
2. Support the baffle and drop in the driver, line up the holes so they look aesthetically placed.
3. Use a vix bit to start a hole in the center of each bolt hole. Make sure the driver doesn't move.
3. Remove the driver and then finish the holes on my drill press using the starter holes to maintain correct positioning... the drill press will ensure the holes are perpendicular.

I'll follow-up with how well this works for me....
 
C

celine hedson

Audiophyte
No it would not. The two drivers have totally different Thiel/Small parameters. Enclosures have to be designed for specific drivers. There are no exceptions.
Oh.. I am totally new to this. What program should i use to calculate a box for the Dayton UM18-22?
and do you have some tips for me? Thanks for answering
 
TLS Guy

TLS Guy

Seriously, I have no life.
Oh.. I am totally new to this. What program should i use to calculate a box for the Dayton UM18-22?
and do you have some tips for me? Thanks for answering
I have not modeled that driver before. However looking at the specs, it is a fairly high Qts driver. I suspect it will model sealed best, and that will require complex Eq.

If you are a beginner it is best to start with a good vented design. That is why I picked the driver I did, to make a sure fire design that a competent woodworker can build.

The driver I selected has all the T/S parameters in the sweet spot for a design like that.

I will play with that driver later and see what I can come up with.
 
C

celine hedson

Audiophyte
I have not modeled that driver before. However looking at the specs, it is a fairly high Qts driver. I suspect it will model sealed best, and that will require complex Eq.

If you are a beginner it is best to start with a good vented design. That is why I picked the driver I did, to make a sure fire design that a competent woodworker can build.

The driver I selected has all the T/S parameters in the sweet spot for a design like that.

I will play with that driver later and see what I can come up with.
Okay thank you so much!
 
TLS Guy

TLS Guy

Seriously, I have no life.
Oh.. I am totally new to this. What program should i use to calculate a box for the Dayton UM18-22?
and do you have some tips for me? Thanks for answering
Speaker design is a little more complex than I think you have considered.

As I suspected the driver you have selected is only suitable for a sealed alignment. A vented box would be over 14 cu.ft! It would also not sound good.

This driver is intended for sealed alignment.

I have enclosed a pdf of an optimal design.

Now as is typical for sealed sub, it starts to roll off at 60 Hz and is 3db down at 32 Hz. So without equalization the performance will not be floor shaking.

Also note that cone movement rapidly increases below 60 Hz. This is because unlike a port, a speaker cones couples poorly to the room.

So to make a decent sub from this driver you need a box with heavy fill of Polyfill and a volume of 3.7 cu.ft internal volume, sealed

Now you will need a lot of power, as that increased cone excursion implies inefficiency. So the design does show room for added Eq without running the driver out of cone excursion.

You will need a powerful amp in the 600 to 1000 watt range. You will need to add a bass boost of 12 db per octave stating at 40 Hz. In order not to damage the driver you will need a high pass filter add 20 Hz of at least 12 db per octave.

Now for other reading this post, the Qtc of the design is just over 0.7. The total Qts of the driver is 0.53.

Now the design can not be lower than the Qts of the driver. For really nice tight bass you need a total Q of the system around 0.5. At 0.7 the bass starts to get a little warm, but acceptable to most. Much higher than this the bass becomes rapidly boomy.

I stress this, as there is a frequently proferred opinion on these forums that a sealed sub is inherently more musical than a sealed one. This is nonsense.

On an bass extension/spl/bass quality dollar for dollar spent the ported design will beet the sealed every time. The caveat is that both must be competently and optimally designed.

So why is this driver the way it is. A sealed design allows for a smaller compact sub.

Next question why is the Qtc of the driver were it is, on the high side? The answer is price. If the Q of the driver were higher, then the bass roll off would be higher. The Eq would have to start higher, the driver would have to handle much more power and a much more powerful amplifier would be required. So the cost and complexity would be increased enormously.

So now you see why I selected the driver I did for Ares Project. He was the one looking for a cost effective slam dunk first build. That was why I designed it the way I did.
 

Attachments

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celine hedson

Audiophyte
Speaker design is a little more complex than I think you have considered.

As I suspected the driver you have selected is only suitable for a sealed alignment. A vented box would be over 14 cu.ft! It would also not sound good.

This driver is intended for sealed alignment.

I have enclosed a pdf of an optimal design.

Now as is typical for sealed sub, it starts to roll off at 60 Hz and is 3db down at 32 Hz. So without equalization the performance will not be floor shaking.

Also note that cone movement rapidly increases below 60 Hz. This is because unlike a port, a speaker cones couples poorly to the room.

So to make a decent sub from this driver you need a box with heavy fill of Polyfill and a volume of 3.7 cu.ft internal volume, sealed

Now you will need a lot of power, as that increased cone excursion implies inefficiency. So the design does show room for added Eq without running the driver out of cone excursion.

You will need a powerful amp in the 600 to 1000 watt range. You will need to add a bass boost of 12 db per octave stating at 40 Hz. In order not to damage the driver you will need a high pass filter add 20 Hz of at least 12 db per octave.

Now for other reading this post, the Qtc of the design is just over 0.7. The total Qts of the driver is 0.53.

Now the design can not be lower than the Qts of the driver. For really nice tight bass you need a total Q of the system around 0.5. At 0.7 the bass starts to get a little warm, but acceptable to most. Much higher than this the bass becomes rapidly boomy.

I stress this, as there is a frequently proferred opinion on these forums that a sealed sub is inherently more musical than a sealed one. This is nonsense.

On an bass extension/spl/bass quality dollar for dollar spent the ported design will beet the sealed every time. The caveat is that both must be competently and optimally designed.

So why is this driver the way it is. A sealed design allows for a smaller compact sub.

Next question why is the Qtc of the driver were it is, on the high side? The answer is price. If the Q of the driver were higher, then the bass roll off would be higher. The Eq would have to start higher, the driver would have to handle much more power and a much more powerful amplifier would be required. So the cost and complexity would be increased enormously.

So now you see why I selected the driver I did for Ares Project. He was the one looking for a cost effective slam dunk first build. That was why I designed it the way I did.

Thank you so much! But I want to use the sub mostly for movies and music that is in the 20-35hz range. Also I have a crown xls 1000 that pumps 1100 watts at 4ohm bridged. Will that sealed box work well with movies and the low music? Thanks for answering again. And your system looks really good!
 
TLS Guy

TLS Guy

Seriously, I have no life.
Thank you so much! But I want to use the sub mostly for movies and music that is in the 20-35hz range. Also I have a crown xls 1000 that pumps 1100 watts at 4ohm bridged. Will that sealed box work well with movies and the low music? Thanks for answering again. And your system looks really good!
Well you have enough amp power. But as with all good sealed designs you need an amp and an equalizer.

Mini DSP is your friend.

This unit should be able to give the required 12 db per octave boost below 40 Hz and the 20 Hz high pass function. That will do what you want. You can also Download REW and wit the help of the measurements equalize it more precisely.

Now make sure you brace the box properly, or it will ring like a barrel. That does not mean stinging a few 2 X 4s. It means interlocking panels, with large holes dadoed to the sides and back. You need to make the speaker panel double thickness.

Finally, remember DIY is not about cheaper systems, but better systems.
 
C

celine hedson

Audiophyte
Well you have enough amp power. But as with all good sealed designs you need an amp and an equalizer.

Mini DSP is your friend.

This unit should be able to give the required 12 db per octave boost below 40 Hz and the 20 Hz high pass function. That will do what you want. You can also Download REW and wit the help of the measurements equalize it more precisely.

Now make sure you brace the box properly, or it will ring like a barrel. That does not mean stinging a few 2 X 4s. It means interlocking panels, with large holes dadoed to the sides and back. You need to make the speaker panel double thickness.

Finally, remember DIY is not about cheaper systems, but better systems.

Yes I can't thank you enough! you are like my hero right now! Thank you so much. I was planning on making the speaker panel double the thickness. im planning on using 2,5cm thick MDF. Is that a good choice? or does it need to be thicker? And do i need to fill the whole box with that polyfill thick or less thick? ive only built a box for my 2 12 inches. its a tline tuned to 30hz. It is really really huge. But those subs make a ticking noise and its also a unknown brand. Thanks for awnsering!
 
TLS Guy

TLS Guy

Seriously, I have no life.
Yes I can't thank you enough! you are like my hero right now! Thank you so much. I was planning on making the speaker panel double the thickness. im planning on using 2,5cm thick MDF. Is that a good choice? or does it need to be thicker? And do i need to fill the whole box with that polyfill thick or less thick? ive only built a box for my 2 12 inches. its a tline tuned to 30hz. It is really really huge. But those subs make a ticking noise and its also a unknown brand. Thanks for awnsering!
MDF is fine. You could use plywood also. You need to fill the box with Polyfill, but it should not be compressed.
 
C

celine hedson

Audiophyte
MDF is fine. You could use plywood also. You need to fill the box with Polyfill, but it should not be compressed.
kkay. thank you for awnsering all my questions. Im starting building soon
 
lsiberian

lsiberian

Audioholic Overlord
I strongly suggest using REW and a measurement mic to setup the EQ.

1. Take 6-8 measurements around your main listening area.
2. Use the summing capabilities of REW to calculate the appropriate filters for the minidsp.
3. Load them into the minidsp and your set.

Oh and there is well respected member selling a minidsp for 75 bucks on this forums classifieds.
 
B

bassjunkie78

Audiophyte
Speakers look great, bet they sound great too. Im actually thinking of upgrading my subwoofers and came across this thread in a search. I went to dayton audio website and it seems the specs on this driver have changed. Not the first time ive seen this happen with dayton. The new specs dont model as well as the old for this particular box, are they changing the design or giving incorredt ts parameters?
 

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