This winter's DIY-project just arrived.

Re: This winter's DIY-project just arrived.

Helge Dr. Bentsen said:
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.
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Hi Helge,

I have not seen a design for a 21 inch keystone, so I have taken a guess. The black trace is with the IPAL driver the grey is with the 21SW152
 

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Re: This winter's DIY-project just arrived.

Evan Kirkendall said:
-6 @ 32hz? Not that impressive, especially for a 21"!

I've got a dual 21" reflex box in the works that is -3 @ 27hz, similar to d&b's J-infra!


Evan
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Box size, efficiency and band-width ... pick any two. It just depends on what you need / want.

I would be interested to see what you have come up with ????

Art's design does an excellent job in this respect. Its most efficient where you need it, goes low enough for general purpose applications and is a reasonable size. In comparison the Orthorn goes lower, is a very reasonable size but is typically 3 dB less efficient. (6 dB 70Hz to 90Hz - with IPAL) http://www.data-bass.com/data?page=system&id=81&mset=87 (21SW152)

(My SIM is just my best guess - I'm sure Art will be able to correct etc.)

FWIW my criteria is different to Helge's, I plan to build some double 21's (21SW152) in a standard reflex enclosure. If I do that I can use them in parallel with my existing double 18's.
 
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Re: This winter's DIY-project just arrived.

Peter: Thanks for the sim :)
Based on them I would say that the Keystone is usable for this driver, it should be pretty easy to eq out a bit of 60-80hz for a flatter response if needed.


Sent from my iPad

Edit:
Evan: Can you share some info on your design?
 
Re: This winter's DIY-project just arrived.

Helge Dr. Bentsen said:
Peter: Thanks for the sim :)
Based on them I would say that the Keystone is usable for this driver, it should be pretty easy to eq out a bit of 60-80hz for a flatter response if needed.


Sent from my iPad

Edit:
Evan: Can you share some info on your design?
Click to expand...

The IPAL diver is quite different to a normal driver; it has a very stiff suspension combined with an EXTREMELY powerful motor, yet has a useable Xmax of 22mm!

That combination will not produce a flat frequency response unless combined with some EQ.

I think that was the idea; design speaker as part of an integral system that included PEQ and a huge amplifier that could drive whatever impedance necessary.

By doing that you can archive the maximum SPL where its needed.

... what ever you do you will need a STRONG box :razz:

Edit - to achieve Xmax on the IPAL it took twice the rated program power (5000 W) in these boxes.
 

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Re: This winter's DIY-project just arrived.

Peter Morris said:
The IPAL diver is quite different to a normal driver; it has a very stiff suspension combined with an EXTREMELY powerful motor, yet has a useable Xmax of 22mm!

That combination will not produce a flat frequency response unless combined with some EQ.

I think that was the idea; design speaker as part of an integral system that included PEQ and a huge amplifier that could drive whatever impedance necessary.

By doing that you can archive the maximum SPL where its needed.

... what ever you do you will need a STRONG box :razz:

Edit - to achieve Xmax on the IPAL it took twice the rated program power (5000 W) in these boxes.
Click to expand...

According to the specs, a IPALMod should put out around 11000W peak. I have no idea if the driver can handle it, but I guess I will find out.
 
Re: This winter's DIY-project just arrived.

Helge Dr. Bentsen said:
According to the specs, a IPALMod should put out around 11000W peak. I have no idea if the driver can handle it, but I guess I will find out.
Click to expand...

An interesting comparison - a single 18" reflex with 9mm of Xmax compared to the 21 IPAL with 22mm of Xmax in a Keystone
 

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Re: This winter's DIY-project just arrived.

Peter Morris said:
Box size, efficiency and band-width ... pick any two. It just depends on what you need / want.

I would be interested to see what you have come up with ????

Art's design does an excellent job in this respect. Its most efficient where you need it, goes low enough for general purpose applications and is a reasonable size. In comparison the Orthorn goes lower, is a very reasonable size but is typically 3 dB less efficient. (6 dB 70Hz to 90Hz - with IPAL) http://www.data-bass.com/data?page=system&id=81&mset=87 (21SW152)

(My SIM is just my best guess - I'm sure Art will be able to correct etc.)

FWIW my criteria is different to Helge's, I plan to build some double 21's (21SW152) in a standard reflex enclosure. If I do that I can use them in parallel with my existing double 18's.
Click to expand...

My benchmark is to beat the dual 18" reflex I came up with last year. It's not a massive box(22x48x32), but it goes low with no corrective EQ down low and has gobs of output!




Evan
 

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Re: This winter's DIY-project just arrived.

Evan, i am very suspicious that the 21 Ipal can beat a box like your double 18.
I have double 18s that are not very far from yours. Only mine a re loaded with a customized variant of 18NLW9601, not the BC.

Couple of years ago i did a TH prototype that was extremely similar to the real TH118. I was curious how they work. There are none of those around so i had to make one.

The A/B test showed that my double 18 went both lower and louder. With more power yes. But, i liked the sound on the 218 more.

I also did a protopype single reflex box with the 21SW152. Sure it went low, afaik it was under 30hz where is started rolling down. But again i didnt liked the tone. Its was very inefficient and sounded very slow with no impact. If you need an infra sub then sure, that driver will do that. But as a one box sub solution it dont work for me.
 
Re: This winter's DIY-project just arrived.

Marjan Milosevic said:
Evan, i am very suspicious that the 21 Ipal can beat a box like your double 18.
I have double 18s that are not very far from yours. Only mine a re loaded with a customized variant of 18NLW9601, not the BC.

Couple of years ago i did a TH prototype that was extremely similar to the real TH118. I was curious how they work. There are none of those around so i had to make one.

The A/B test showed that my double 18 went both lower and louder. With more power yes. But, i liked the sound on the 218 more.

I also did a protopype single reflex box with the 21SW152. Sure it went low, afaik it was under 30hz where is started rolling down. But again i didnt liked the tone. Its was very inefficient and sounded very slow with no impact. If you need an infra sub then sure, that driver will do that. But as a one box sub solution it dont work for me.
Click to expand...

If you want to produce bass, it’s all about the amount of air you can move.

Typically the best 18" pro drivers we use have an Xmax of about 1.4 cm and a cone area of 1225 sq cm. They can displace a volume of (Vd) 1775 cc. The IPAL 21 has an Xmax of 2.2 cm and a cone area of 1680 sq cm giving a Vd of 3696 cc which is twice that of the 18".

If you are able use that Xmax correctly in a suitable enclosure, the IPAL should be able to produce about the same SPL as a double 18.

The trick is finding and processing a suitable box that will give you output where you need it …. and sounds good.

(also note that the efficiency of the IPAL21 is very high - 99 dB/w/m)
 
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Re: This winter's DIY-project just arrived.

Any ideas how to manipulate a cabinet into more punch factor? Could for example the damping control feature on Powersoft amps(I already have an SAE 1450 so won't go down this route but wondering) create this, or other dsp?

I have other cabs which punch great with detailed transient response from the 30 hz area all the way up to 120 and want to create the same(somewhat) effect with this new cab i've built, which is much louder. Is it possible to get a cabinet with clean very high output but with a lacking transient response ("Mushy" sounding) to punch very hard in the transients(not to be misunderstood as the frequency kick register).
 
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Re: This winter's DIY-project just arrived.

Punch is more how the driver and enclosure interact with the air, than after the fact processing. The damping factor compensation only has an effect on long and/or thin gauge speaker wire between the amp and the sub, not on how the sub performs.
 
Re: This winter's DIY-project just arrived.

Ossian Ott said:
Any ideas how to manipulate a cabinet into more punch factor? Could for example the damping control feature on Powersoft amps(I already have an SAE 1450 so won't go down this route but wondering) create this, or other dsp?

I have other cabs which punch great with detailed transient response from the 30 hz area all the way up to 120 and want to create the same(somewhat) effect with this new cab i've built, which is much louder. Is it possible to get a cabinet with clean very high output but with a lacking transient response ("Mushy" sounding) to punch very hard in the transients(not to be misunderstood as the frequency kick register).
Click to expand...

Better transient response means better high frequency response. If you want more "punch", you should focus on properly aligning your subs to your tops.
 
Re: This winter's DIY-project just arrived.

Peter Morris said:


(also note that the efficiency of the IPAL21 is very high - 99 dB/w/m)
Click to expand...

It is 99db at 1ohm. That is the trick there. Calculate that back and it is not as sensitive as you think it is :-).
Check out the graph that is at the bottom of the spec of the IPAL21 that is showing the REAL 1w/1m result in a 200lit box tuned at 40HZ.
It is more like 94db.
The module that powers it is 8500W at 1 ohm. So the only saving here is the size. Nothing else. But at the expense of power and initial investment.
I was thinking very hard weather to go in to the Ipal adventure my self couple of years ago and have decided against it.
Now that dilemma still exists, but it is about the M-force.
 
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Re: This winter's DIY-project just arrived.

Marjan Milosevic said:
It is 99db at 1ohm. That is the trick there. Calculate that back and it is not as sensitive as you think it is :-).
Check out the graph that is at the bottom of the spec of the IPAL21 that is showing the REAL 1w/1m result in a 200lit box tuned at 40HZ.
It is more like 94db.
The module that powers it is 8500W at 1 ohm. So the only saving here is the size. Nothing else. But at the expense of power and initial investment.
I was thinking very hard weather to go in to the Ipal adventure my self couple of years ago and have decided against it.
Now that dilemma still exists, but it is about the M-force.
Click to expand...
It’s not 99 dB @ 2.83V (Danley style:)~:-)~:smile: ), it is actually 99 dB per watt per metre. The T/S parameters for this speaker are very unusual.

It’s a 21 inch driver with a Qt of 0.21, Mms 440, Vas 155, Fs of 37Hz and a BL^2/RE product of 521 with 22mm of Xmax.

These parameters will produce a rapidly rising sensitivity toward the top end of its intended operating range. The driver was clearly design to be used in conjunction with signal processing.

As I said above, the trick will be taking advantage of these unusual parameters and the 22mm of Xmax. If you don’t, a “normal” driver probably would have been a better choice.

For comparison:
ηo- The reference or "power available" efficiency of the driver (%).
21IPAL = 3.2%
21SW115 = 2.6%
21SW152 = 2.2%

BTW I am VERY interested it what you do with the M- Force … keep in touch with that one.
 
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