This winter's DIY-project just arrived.
- Thread starter Helge A. Bentsen
- Start date
Re: This winter's DIY-project just arrived.
Keep us posted on the build. Like watching this stuff even though I usually end up buying MI stuff
~:-(~:sad:
Keep us posted on the build. Like watching this stuff even though I usually end up buying MI stuff
~:-(~:sad:Re: This winter's DIY-project just arrived.
For the cost of the IPAL, I'd want to get the additional 6 dB of output available from a tapped horn.
Wish I had them to play with, Merry Christmas!
Art
Helge,
For the cost of the IPAL, I'd want to get the additional 6 dB of output available from a tapped horn.
Wish I had them to play with, Merry Christmas!
Art
Re: This winter's DIY-project just arrived.
Sadly, I don't have the knowledge to design a tapped horn. But I'm willing to learn if someone can show me howto.
Sadly, I don't have the knowledge to design a tapped horn. But I'm willing to learn if someone can show me howto.
Re: This winter's DIY-project just arrived.
Maybe a chance for a collaborative effort that can become another awesome sticky!!
Maybe a chance for a collaborative effort that can become another awesome sticky!!
Re: This winter's DIY-project just arrived.
There are several designs already available that would work with the IPAL, you don't need to do any design work at all if you don't want to. Keystone sub, Othorn, Gjallerhorn would be a short list in ascending size and descending low frequency cut off frequency. As usual, Hoffman's Iron law applies: Low, Loud, Small- pick any two. However, the IPAL will be loud in whatever you put it in, but having one (with a little more plywood expense) do the same output as two is a big deal.
Designing to fit your needs is preferable, and not that difficult to tweak existing designs slightly to fit your parameters.
Art
Helge,
There are several designs already available that would work with the IPAL, you don't need to do any design work at all if you don't want to. Keystone sub, Othorn, Gjallerhorn would be a short list in ascending size and descending low frequency cut off frequency. As usual, Hoffman's Iron law applies: Low, Loud, Small- pick any two. However, the IPAL will be loud in whatever you put it in, but having one (with a little more plywood expense) do the same output as two is a big deal.
Designing to fit your needs is preferable, and not that difficult to tweak existing designs slightly to fit your parameters.
Art
Re: This winter's DIY-project just arrived.
Thanks for the tip, I haven't considered modifying anyting existing.
What would you consider to be the best design to modify if I go for Low&Loud? This doesn't have to be truck pack friendly in any way as long as I'm able to move it by myself.
Edit: I had a look at your Keystone sub, it looks promising. To my mind the big issue will be where to put the amp module. Do you think there's room for it?
Thanks for the tip, I haven't considered modifying anyting existing.
What would you consider to be the best design to modify if I go for Low&Loud? This doesn't have to be truck pack friendly in any way as long as I'm able to move it by myself.
Edit: I had a look at your Keystone sub, it looks promising. To my mind the big issue will be where to put the amp module. Do you think there's room for it?
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Re: This winter's DIY-project just arrived.
FWIW when you compare tapped horns, pure horns, bass reflex, and band-pass designs taking in to account SPL, box size and band width they are all similar … roughly
A typical single 18” tapped horn is almost as big as a double 18. The both have similar outputs; the tapped horn is slightly smaller but has less band-width, the box is more complex to build but you save the cost of one driver.
You can model horns, tapped horns and reflex enclosures with is program.
http://www.hornresp.net/
When you model the Othorn you find that you don’t get much gain (2-3 dB) because the box / horn is too small. Many of the DIY designs are like this.
The Gjallerhorn sacrifices extension for SPL and is useful down to 16Hz … not what you want.
In contrast Danley’s Tapped horns and Arts Keystone look very good in terms of maximum output and a suitable frequency response, typically +6dB
There is some info here that maybe of interest.
http://www.data-bass.com/systems
FWIW when you compare tapped horns, pure horns, bass reflex, and band-pass designs taking in to account SPL, box size and band width they are all similar … roughly
A typical single 18” tapped horn is almost as big as a double 18. The both have similar outputs; the tapped horn is slightly smaller but has less band-width, the box is more complex to build but you save the cost of one driver.
You can model horns, tapped horns and reflex enclosures with is program.
http://www.hornresp.net/
When you model the Othorn you find that you don’t get much gain (2-3 dB) because the box / horn is too small. Many of the DIY designs are like this.
The Gjallerhorn sacrifices extension for SPL and is useful down to 16Hz … not what you want.
In contrast Danley’s Tapped horns and Arts Keystone look very good in terms of maximum output and a suitable frequency response, typically +6dB
There is some info here that maybe of interest.
http://www.data-bass.com/systems
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Re: This winter's DIY-project just arrived.
I was wondering where those went...
Have you been to Josh Ricci's forum, Helge? There's a few folks who have designed cabinets around the 18" or 21" IPAL woofers, some of them are using home theater style amplifiers to drive them. You don't get the feedback loop present in the Powersoft IPALMOD, but in the end a woofer with a big motor and efficient low-Z coil is still a woofer.
http://www.data-bass.com/data?page=driver&id=54
I was wondering where those went...
Have you been to Josh Ricci's forum, Helge? There's a few folks who have designed cabinets around the 18" or 21" IPAL woofers, some of them are using home theater style amplifiers to drive them. You don't get the feedback loop present in the Powersoft IPALMOD, but in the end a woofer with a big motor and efficient low-Z coil is still a woofer.
http://www.data-bass.com/data?page=driver&id=54
Re: This winter's DIY-project just arrived.
I had a look over there during my driver selection, some really impressive designs and a lot of data
The Othorn looks nice, but the Keystone looks like an easier build for someone like me that's not a master woodworker.
I'm gong to get the Powersoft Ipalmod, but I have a K20 around if I just want to make some noise
I had a look over there during my driver selection, some really impressive designs and a lot of data
The Othorn looks nice, but the Keystone looks like an easier build for someone like me that's not a master woodworker.
I'm gong to get the Powersoft Ipalmod, but I have a K20 around if I just want to make some noise
Re: This winter's DIY-project just arrived.
Don't know what size your amp module is, probably an additional box to contain it on the top or bottom would work best.
Re: This winter's DIY-project just arrived.
I'm looking at an external box solution right now. The amp module is roughly 520x175x60mm
Do you think the driver will fit in there? It's 269mm deep according to the datasheet.
http://bcspeakers.s3.amazonaws.com/2015/01/20/11/26/52/756/21IPAL.pdf
Obviously one needs to modify the baffle with a larger hole, but I'm more concerned with there being enough depth inside for the driver.
I'm looking at an external box solution right now. The amp module is roughly 520x175x60mm
Do you think the driver will fit in there? It's 269mm deep according to the datasheet.
http://bcspeakers.s3.amazonaws.com/2015/01/20/11/26/52/756/21IPAL.pdf
Obviously one needs to modify the baffle with a larger hole, but I'm more concerned with there being enough depth inside for the driver.
Re: This winter's DIY-project just arrived.
Helge,
I would recommend you model the IPAL in some of these boxes first. It has some unusual properties and doesn’t model well in the Othorn, there is a big dip at 80Hz …. I don’t know about the Keystone.
Helge,
I would recommend you model the IPAL in some of these boxes first. It has some unusual properties and doesn’t model well in the Othorn, there is a big dip at 80Hz …. I don’t know about the Keystone.
Re: This winter's DIY-project just arrived.
As Peter mentioned, best to do some modeling, but one advantage of the Keystone over many TH designs is the exit can be altered, which changes the upper frequency response.
Part "P",(upper exit cleat) might need an arc cut out in the center for the magnet, try substituting the 21 IPAL profile in the plans and see. The depth (and/or width) could be increased proportionately for the larger displacement driver and would increase output compared to the size designed for the BC18SW115, and my trailer pack ;^).I'm looking at an external box solution right now. The amp module is roughly 520x175x60mm
Do you think the driver will fit in there? It's 269mm deep according to the datasheet.
http://bcspeakers.s3.amazonaws.com/2015/01/20/11/26/52/756/21IPAL.pdf
Obviously one needs to modify the baffle with a larger hole, but I'm more concerned with there being enough depth inside for the driver.
As Peter mentioned, best to do some modeling, but one advantage of the Keystone over many TH designs is the exit can be altered, which changes the upper frequency response.
Re: This winter's DIY-project just arrived.
Sadly Hornresp doesn't play well on my computer, or I'm missing something fundamental with that program.
I get a L12=0 or L34=0 error no matter what I try.
Sadly Hornresp doesn't play well on my computer, or I'm missing something fundamental with that program.
I get a L12=0 or L34=0 error no matter what I try.
Re: This winter's DIY-project just arrived.
IIRC you need to specify expansion type for a segment before you enter its length - easiest way is to type the appropriate letter after you've already selected that field but before you try and key in the length.
The main ones are: C for conical, E for exponential, H for hyperbolic, P for Parabolic & T for tractrix, not sure if there are any more in the latest versions of HornResp.
Apologies if that's already what you're doing - if so, there might be something else wrong as you suggest.
Edit: typo
IIRC you need to specify expansion type for a segment before you enter its length - easiest way is to type the appropriate letter after you've already selected that field but before you try and key in the length.
The main ones are: C for conical, E for exponential, H for hyperbolic, P for Parabolic & T for tractrix, not sure if there are any more in the latest versions of HornResp.
Apologies if that's already what you're doing - if so, there might be something else wrong as you suggest.
Edit: typo