I think the DNA may be better off with its own thread I started here: http://www.diyaudio.com/forums/full-range/235457-decware-dna-horn.html#post3479807
I just posted simulations of the DNA BLH in the new thread. Short story is that it is a good design. For the cheap MCM 55-1870 driver, reduce the driver chamber volume to about 10 liters. Instead of a round hole between the driver chamber and main horn, an equivalent 0.70 in wide x 7 in deep slot can work just as well.
Here is the simulation for the MCM driver:
With stuffing in driver chamber the peaks dshould go away.
I just posted simulations of the DNA BLH in the new thread. Short story is that it is a good design. For the cheap MCM 55-1870 driver, reduce the driver chamber volume to about 10 liters. Instead of a round hole between the driver chamber and main horn, an equivalent 0.70 in wide x 7 in deep slot can work just as well.
Here is the simulation for the MCM driver:
With stuffing in driver chamber the peaks dshould go away.
I love this Thread!
Hi everyone.
This is my first time posting anything within the speaker section of the forum. Been reading through the FR section with keen interest and loved the idea of putting together some foam board speakers just for fun...
Bought some 10Watt 8Ohm 3" No-Name drivers of e-bay and a pack of foam board of Amazon. Then spent some time putting together these micro FonKen based enclosures...
Aim was to make some test speakers for an 8 Watt amp that's under construction. After a brief test, they sound good but completely lack any LF. Plus, the cabs could have done with dampening material internally beyond the lambs wool [as is recommended], as they just radiate the sound every which way... Still detailing is good enough...
Had fun and might give a few stranger designs a go in the near future...
Paul
Hi everyone.
This is my first time posting anything within the speaker section of the forum. Been reading through the FR section with keen interest and loved the idea of putting together some foam board speakers just for fun...
Bought some 10Watt 8Ohm 3" No-Name drivers of e-bay and a pack of foam board of Amazon. Then spent some time putting together these micro FonKen based enclosures...
Aim was to make some test speakers for an 8 Watt amp that's under construction. After a brief test, they sound good but completely lack any LF. Plus, the cabs could have done with dampening material internally beyond the lambs wool [as is recommended], as they just radiate the sound every which way... Still detailing is good enough...
Had fun and might give a few stranger designs a go in the near future...
Paul
Attachments
Buildmesomething,
Wow! Those cabinets look fantastic!
You are one of the first people to use the foam core as if it were wood. I see rabbet joints, dados, etc. The fit and finish, I have to say, is the best I have ever seen anyone do in FC! Sorry you did not get much bass out of this design. It may be a mostly due to the driver/cabinet combo. Did you design the cabinet volume/slot dimensions based on the T/S parameters of the drivers you purchased? Because the uFonken cabinets have pretty good bass for a 3 incher when paired with something like FF85wk, from what I have heard. 
Keep up the excellent work. Might I suggest you try a MLTL with a 3 in driver if you want bass? Or be one of the first to try the DNA horn with the budget NS525 driver - that thing WILL have lots of bass, down into 30 Hz. Thanks for sharing.
Regards,
X
Your craftsmanship is really inspiring.
Wow! Those cabinets look fantastic!
You are one of the first people to use the foam core as if it were wood. I see rabbet joints, dados, etc. The fit and finish, I have to say, is the best I have ever seen anyone do in FC! Sorry you did not get much bass out of this design. It may be a mostly due to the driver/cabinet combo. Did you design the cabinet volume/slot dimensions based on the T/S parameters of the drivers you purchased? Because the uFonken cabinets have pretty good bass for a 3 incher when paired with something like FF85wk, from what I have heard. Keep up the excellent work. Might I suggest you try a MLTL with a 3 in driver if you want bass? Or be one of the first to try the DNA horn with the budget NS525 driver - that thing WILL have lots of bass, down into 30 Hz. Thanks for sharing.
Regards,
X
Your craftsmanship is really inspiring.
Ken,
The DNA horn is a design by Steve Deckert, aka Decware. It is the subject of the named thread. Check it out - you would be interested in this design. So far it looks like it may be the budget design of all time with a $3.60 driver and maybe 3 or 4 sheets of FC and should reach 30 Hz with authority. My simulations show that it is a real good design with bass potential. Being a rear firing horn mouth, the sound should sound bigger than its diminutive size may suggest.
The plan is here. Print it out to scale using tiles in PDF print function.
http://www.diyaudio.com/forums/attachments/full-range/346533d1367668305-foam-core-board-speaker-enclosures-decware-dna-dimensions.pdf
The DNA horn is a design by Steve Deckert, aka Decware. It is the subject of the named thread. Check it out - you would be interested in this design. So far it looks like it may be the budget design of all time with a $3.60 driver and maybe 3 or 4 sheets of FC and should reach 30 Hz with authority. My simulations show that it is a real good design with bass potential. Being a rear firing horn mouth, the sound should sound bigger than its diminutive size may suggest.
The plan is here. Print it out to scale using tiles in PDF print function.
http://www.diyaudio.com/forums/attachments/full-range/346533d1367668305-foam-core-board-speaker-enclosures-decware-dna-dimensions.pdf
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Thanks for the information. It looks like a real jigsaw puzzle for MDF or wood but in foam it might be easy. I am dubious of "miracle" enclosures promising bass beyond the physics involved but I will give it a try. I have some of the newly released Audience three inch full range drivers and will try one in the DNA. Will post the results.
Ken,
The implementation of the DNA in FC is indeed simple: the one long stretch internal wall with lots of folds can actually done in one piece with scoring to provide the bends and folds. It is no miracle beyond physics as I have modeled it in AkAbak (with physics) and it does show that it has deep bass extension. You can't just stick your 3 in Audience in it and expect it to work though - get me the T/S params for your driver and I will see what the simulation predicts - maybe there is some optimization to cabinet size, throat or volume that may help.
The implementation of the DNA in FC is indeed simple: the one long stretch internal wall with lots of folds can actually done in one piece with scoring to provide the bends and folds. It is no miracle beyond physics as I have modeled it in AkAbak (with physics) and it does show that it has deep bass extension. You can't just stick your 3 in Audience in it and expect it to work though - get me the T/S params for your driver and I will see what the simulation predicts - maybe there is some optimization to cabinet size, throat or volume that may help.
Thanks X & K ... Looked at a FC building guild by a Warhammer gamer, who recommended using rabbet joints etc. for stronger joints, so I went with that in full...
Unfortunately, I was unable to find any details about the driver. Only what the seller posted for the sale, details say 120Hz - 16KHz so wasn't expecting to much. Will have to do a frequency sweep to find how low they go... And pick music that suites.
Those DNA Horns look impressive, will have a look at driver availability here in the UK... Thanks again
Edit: just priced up a pair of NS525 drivers shipped to the UK from Madisound, $54.81... $47.61 is shipping Not found any info on a UK source yet.
Unfortunately, I was unable to find any details about the driver. Only what the seller posted for the sale, details say 120Hz - 16KHz so wasn't expecting to much. Will have to do a frequency sweep to find how low they go... And pick music that suites.
Those DNA Horns look impressive, will have a look at driver availability here in the UK... Thanks again
Edit: just priced up a pair of NS525 drivers shipped to the UK from Madisound, $54.81... $47.61 is shipping
Not found any info on a UK source yet.
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Note that the first segment is the throat from driver chamber. In the model it is connected at a node in between segments 2 and 3 which are really the same segment immediately above the driver chamber. The axial distances are measured from the midpoint of the cross sectional area lines located between the corners and vertices. You can see examples of how this is done in the MJK whitepapers. In reality, segment 1 is a round hole but for ease of modeling I made it an equivalent area slot of width 0.7 in x 7 in deep to equal a 2.5 in dia hole. I am guessing the dia may be 2 in. The model is not too sensitive to this cross section. It will control how high the upper frequency that leaks our onto and beyond he horn.
Uneven Length Double BLH sim
I did the sim in the Akabak thread but doesn't look like it got noticed there. This may be best to try out in FC first.
http://www.diyaudio.com/forums/full-range/235846-running-akabak-2.html#post3496353
Here is the sim with two horns (red and green) black is the combined. I used a bk12m as a starting point and divided the horn paths into two layers with different lengths and mouth sizes. I used an FF105wk with a smaller driver chamber as the base case. In looking for a cheap driver to try I stuck the vifa tc9fd in and reduced the driver chamber volume to half of the fostex and surprisingly it is very well behaved, albeit with spl reduced to 89 db level.
So a cheap experiment in FC awaits.
I did the sim in the Akabak thread but doesn't look like it got noticed there. This may be best to try out in FC first.
http://www.diyaudio.com/forums/full-range/235846-running-akabak-2.html#post3496353
Here is the sim with two horns (red and green) black is the combined. I used a bk12m as a starting point and divided the horn paths into two layers with different lengths and mouth sizes. I used an FF105wk with a smaller driver chamber as the base case. In looking for a cheap driver to try I stuck the vifa tc9fd in and reduced the driver chamber volume to half of the fostex and surprisingly it is very well behaved, albeit with spl reduced to 89 db level.
So a cheap experiment in FC awaits.
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