Dayton Classic 18" DCS-450 - Tapped Horn?

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I got a deal on a Dayton Classic 18 and would like to put it in a tapped horn. I have read through the collaborative tapped horn thread(!), which is slightly overwhelming. I don't mind fiddling with HornResp, but I would like some recommendations. I also need help taking the HornResp data to actual plans. Carpenter posted plans for an 18" TH, which I attached. The tallest I could go is about 94".

Included some pics of my 2 x Exodus DPL-15 IB :cool:.
 

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Bjorno,
Thank you for the information.

I am reading about TQWT and what little I can find about T-TQWT. I even figured out how to use HR to calc T/S parms :) I am hoping to get a box designed and built within the next 10 to 14 days. I will post plans and build pics. Is the any difference between slotted and circular ports for S4?
 
Here are plans I came up with based on Bjorno's drawing and the HR data listed above. I have not included the bracing yet.

Do the yellow dots in the drawing represent stuffing?

If someone will verify that the plans are close enough, I will begin building. I would also be happy to post the sketchup file if anyone is interested.
 

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Sawdust!

I converted it to inches so I could get it cut at Home Depot. The sketchup model I used is attached. Should have build pics within a few days. I'll update the model to include the access panel when I get to that point. Be advised that this has yet to be built and/or tested.

Front / Back (2) 54 1/8" x 20"
L Side / R Side (2) 54 1/8" x 20 5/8"
Top / Bottom (2) 18 1/2" x 20 5/8"
Baffle (1) 18 1/2" x 43 1/4"
 

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I finally got my camera. Here are pics of the assembled box. Testing with a Dayton 240w plate amp. The the sound level and range is impressive. I used 2x2" bracing in the vertical corners, and to make assembly faster.

I also built a scaled down version for a $30 12" PE buyout sub that I picked up, which is also impressive. I may start a new 'budget T-TQWT' thread for that one, <$100 for everything but the amp.

Thanks again bjorno!
 

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I too am curious about reverse taper tapped horns. From what fiddling I've done it seems they tend to further spread the bandpass while sacrificing some efficiency.

FWIW here's some rules of thumb I've gotten from playing with hornresp and akabak. It should be emphasized that I have not tested all of this with actual builds and measurement:

You can generally get a good response with a mouth size ~ driver sd. A mouth size double sd gets you +3dB output. Then, varying S1 affects the smoothness of the response: at some middle point ripple in the bandpass region is minimized to some amount (determined by driver q). S1 larger than this lowers f3/f10 at the cost of increasing the peaks and dips. S1 smaller than this raises f3/f10 up to some point, then increases the peaks and dips. Minimum ripple seems to be around 1/10th mouth size.
Varying L12 and L34 shifts the ripples around somewhat.
 
I finally got my camera. Here are pics of the assembled box. Testing with a Dayton 240w plate amp. The the sound level and range is impressive. I used 2x2" bracing in the vertical corners, and to make assembly faster.

I also built a scaled down version for a $30 12" PE buyout sub that I picked up, which is also impressive. I may start a new 'budget T-TQWT' thread for that one, <$100 for everything but the amp.

Thanks again bjorno!

Cool. Impressive compared to what? i.e. have you tried the drivers in other designs?

What's the freq. response like? Do you get a clean 20 Hz indoors?
 
Well my K15 with undersized 12" hole and oversized SigmaPro18" hiding behind seems
quite similar to what I see in this sub's photo. Mine worked much better after I had
opened the hole to the full size. Mind you though, I was only choking the front side
of the driver, not the whole front of the inverted horn mouth.
 
Well my K15 with undersized 12" hole and oversized SigmaPro18" hiding behind seems
quite similar to what I see in this sub's photo. Mine worked much better after I had
opened the hole to the full size. Mind you though, I was only choking the front side
of the driver, not the whole front of the inverted horn mouth.


Not quite. Your K15/18/12 had hardly any clearance between the baffle and the driver (more similar to the gawd awful ripole sub i built two weeks ago), whereas in this case, the opening is part of the horn terminus. In this case, if I remember the theory, the terminus openingcross sectional area = hornresp specified Sx (x = last segment), ... and the negative taper is necessary to achieve a lower freq. response.
 
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Your ripole had completely different issues. I don't see any similarity.
Mine was choked in the focus of the cone, yours off to one side...

The acoustic short circuit around K15 shelf might be of about the
same as a ripole, but a huge difference how extra air gets swept
up in tapped horn and K effect and added to the wavefront that
radiates into the room.
 
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what I'd like to know is what easy mod might be done to the simple one-fold inverse or positive taper tapped horn/pipe to mitigate their typical suckout

7.4 cubic foot inverse tapered pipe with 15" Dayton 295070 speaker vs 7.7 cubic foot K15 with Audio Nirvana Super10 - one trace has the mouth panel removed giving an opening larger than Sd - tuning and cutoff are a bit higher - for an experiment a Karlson slot might be used.
An externally hosted image should be here but it was not working when we last tested it.

Input impedance with 295070
An externally hosted image should be here but it was not working when we last tested it.

to keep a pipe looking like a Karlson, and give it a positive flare with somewhat higher cutoff in a given bulk perhaps "this"
An externally hosted image should be here but it was not working when we last tested it.
 
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