2 ohms woofers is this the future for cabinets

I believe this to be the next step in transducer tech, current drive, if you impedance compensate the BL rating to 8 ohms you end up with beautiful numbers, ad to that the power handling and Xmax and you end up with a monster of a driver, the limitations reside in how we perceive the technology, voltage driving a system where the BL is current dependent is curious in many ways.

The ts parameters clearly say "put me in enormous horn" Neither br nor any another enclosure type will fit.

this to me merits more investigation before I can commit to the same statement, BR enclosures are flawed in many ways not immediately apparent in the small signal domain, so to me BR is not the reference by any means, although the design principle does allow for some serious sub tuning (25 Hz and up) in a relatively small form factor.

Try simulating the 18IPAL in say this one :

http://www.martinsson.cc/blog/index.php?m=03&y=17&entry=entry170302-172317

or the 21IPAL in the :

http://www.martinsson.cc/blog/index.php?m=03&y=17&entry=entry170302-170401

And you will find that it just might work, you will however end up with horrendous compression effects but this is partly why the transducers are built the way they are, oh, and the design might need some additional bracing :)



Edited by martinsson - 24 May 2017 at 8:04pm

Ricci wrote: Elliot Thompson wrote: This speaker may be ideal for a small area where you need to extract every bit of SPL out of a single loudspeaker such as a vehicle or household. However in the Pro Audio world, when you start calculating how much money is going to be invested in acquiring the proper amount drivers to attain the correct coverage  Exactly. However pro audio is also heading in the direction of attempting to extract more output and extension from less size and weight. It's not just home or car audio. This is accomplished through drivers with higher efficiency and more displacement capability + the thermal power handling to use it. Otherwise we'd still be using the drivers from 30 years ago, in huge cabinets, with 400w ratings and 5mm xmax. Moving 8 cabs that can perform on par with 12 of another while being 2/3rds the space and weight sounds good right? Unfortunately the side affect is increased up front cost for the hardware to do that. for some it will be worth it. For others it will not.

Whether today or, three decades ago, there will always be those trying to extract every bit of SPL with the least amount of woofers. 

Have you noticed only the little guys or those just getting in the business have that kind of mentality and not the ones that understand the importance of proper coverage using quantity in order to maintain the longevity of their woofers when reinforcing to the masses?

It is called maturity. Having a good understanding on what is needed in order to get the job done properly with no casualties (blown woofers) before the event is over. So logically, before we invest, we need to make sure the item in question will offer benefits far greater than what we currently use to justify such expenditure.  

High efficiency does not equate to lower extension when it comes to woofers. The TS Parameters has proven that time and time again. What many companies do is offer ample amounts of xmax which allows the user to force the lower frequencies out with the aid of heavy equalisation and extracting lots of amplifier power.

The 21 inch driver in question offers a frequency drop before 100 Hz. That graph is directly from the manufacture. It is a prime example of forcing the driver to play lower frequencies by the means of heavy equalisation and extracting lots of amplifier power.  Hence, the reason it is rated 2 ohms nominal load.

Best Regards,  




Edited by Elliot Thompson - 24 May 2017 at 10:28pm

Elliot Thompson wrote: Ricci wrote: <p ="msonormal"=""> Elliot Thompson wrote: This speaker may be ideal for a small area where you need to extract every bit of SPL out of a single loudspeaker such as a vehicle or household. However in the Pro Audio world, when you start calculating how much money is going to be invested in acquiring the proper amount drivers to attain the correct coverage <p ="msonormal"=""><o:p> Exactly. However pro audio is also heading in the direction of attempting to extract more output and extension from less size and weight. It's not just home or car audio. This is accomplished through drivers with higher efficiency and more displacement capability + the thermal power handling to use it. Otherwise we'd still be using the drivers from 30 years ago, in huge cabinets, with 400w ratings and 5mm xmax. Moving 8 cabs that can perform on par with 12 of another while being 2/3rds the space and weight sounds good right? Unfortunately the side affect is increased up front cost for the hardware to do that. for some it will be worth it. For others it will not.  </o:p> Whether today or, three decades ago, there will always be those trying to extract every bit of SPL with the least amount of woofers.  Have you noticed only the little guys or those just getting in the business have that kind of mentality and not the ones that understand the importance of proper coverage using quantity in order to maintain the longevity of their woofers when reinforcing to the masses? It is called maturity. Having a good understanding on what is needed in order to get the job done properly with no casualties (blown woofers) before the event is over. So logically, before we invest, we need to make sure the item in question will offer benefits far greater than what we currently use to justify such expenditure.   High efficiency does not equate to lower extension when it comes to woofers. The TS Parameters has proven that time and time again. What many companies do is offer ample amounts of xmax which allows the user to force the lower frequencies out with the aid of heavy equalisation and extracting lots of amplifier power. The 21 inch driver in question offers a frequency drop before 100 Hz. That graph is directly from the manufacture. It is a prime example of forcing the driver to play lower frequencies by the means of heavy equalisation and extracting lots of amplifier power.  Hence, the reason it is rated 2 ohms nominal load. Best Regards,

You may want to take a look at an AES paper by Karl Erik Stahl 'Synthesis of Loudspeaker Mechanical Parameters by Electrical Means:
A New Method for Controlling Low-Frequency Loudspeaker Behaviour'
Presented at the 61st convention of rhe Audio Enfineering Society, New York, 1978, etc.

I qoute: 'The ACE-bass method takes advantage of this interaction to control all three basic mechanical of a loudspeaker: the moving mass, the damping and compliance.'....
'It is necessary to eliminate the mainly resistive voice_ coil impedance'.

No doubt there has been a lot of work done on this since that is being applied by in the ipal 'system'. It is very much a 'system of matched amp driver and cabinet.

This is not just a case of throwing dsp at a loudspeaker or being stuck in the 70’s, just that it has taken over 30 years to make use of a tech first described in the 70’s.

Re read the post by Martinsson and also dig out the paper I referenced, as going by what you have posted so far you appear to completely miss understand the concept of this drver.
Also as gen0me states. - tweakable t/s parameters.

Edited by fatfreddiescat - 25 May 2017 at 10:42am

With the IPAL series of bass-drivers you can lower distortion substantially by using an amplifier with a negative output impedance (the ACE-bass patent mentioned earlier and in the IPAL technology white paper) or even better use a servo-loop feedback to force the driver to the desired response. This stresses the voice-coil and cone much more then normal voltage-drive amps with some EQ.

It is not so much what happens with steady state sine-waves, but more about what happens in in real life applications with a very dynamic and transient program material. The peak thermal and structural stresses can become huge (dropped microphone etc) when the servo feedback or the negative output impedance forces the full voltage output of the amp to compensate for the resonant behavior of a br-box or a horn-enclosure.

The 3 or 6 dB extra headroom is not very important compared to lowering the distortion and controlling the tonal and dynamic character of the bass in very high output real life use.

Anyone can put a 1000 horsepower supercharged hemi bigblock in a 1998 Fiat Punto. The trick is to control all that power and transform it into speed and roadholding qualities at those speeds.

Cheers,
Johannes