2 ohms woofers is this the future for cabinets |
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martinsson
Registered User Joined: 19 June 2007 Location: Sweden Status: Offline Points: 325 |
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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.
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 |
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Swedish Pro-fi diy-nerd - http://www.martinsson.cc/blog/
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gen0me
Young Croc Joined: 20 February 2016 Location: UK Status: Offline Points: 999 |
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Hmm for tweakeable ts parameters horns mountains can be also flattened. Could be helpfull in diy too.
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Elliot Thompson
Old Croc Joined: 02 April 2004 Location: United States Status: Offline Points: 5176 |
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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 |
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Elliot Thompson
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Sypa
Young Croc Joined: 21 February 2013 Location: Croatia Status: Offline Points: 921 |
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I just know i stood infront of some martin asx , it was something else.
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fatfreddiescat
Young Croc Joined: 15 October 2010 Location: N.E.Wales Status: Offline Points: 1083 |
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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. |
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Elliot Thompson
Old Croc Joined: 02 April 2004 Location: United States Status: Offline Points: 5176 |
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You do realise that the TS Parameters of drivers designed in 1978 are completely different than those made in 2017. I would suggest you start measuring loudspeakers designed in the 1970’s and you will see how a lot of old loudspeaker notes from AES authors will not correlate with speakers made today. Particularly when it comes to what AES Authors in the Pro Audio Industry considered low bass in the 1970’s and what many Pro Audio users consider low bass today. Digital processing can force a loudspeaker to do many things in which, a lot of companies are capitalising on today. The keyword is force. There is always a side affect that many companies do not bring to your attention when doing so. They do their best to prevent any mishaps when operating the loudspeaker(s) under the given conditions. However, if you are not savvy enough to understand those ramifications in going such a route and, keep moving blindly, you are at the realm of marketer promoting the product. Keep in mind this is the Bass Reflex forum where many are not willing to sacrifice low frequency extension just to attain 3 decibels more. That can be rectified by adding an additional loudspeaker within the audio chain. If that is not your cup of tea, then you should consider using a bass horn where you can reap the benefits a lot of SPL at the expense of low frequency extension. Best Regards, Edited by Elliot Thompson - 25 May 2017 at 9:05am |
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Elliot Thompson
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fatfreddiescat
Young Croc Joined: 15 October 2010 Location: N.E.Wales Status: Offline Points: 1083 |
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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.
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Elliot Thompson
Old Croc Joined: 02 April 2004 Location: United States Status: Offline Points: 5176 |
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The correlation between some loudspeakers designed today and DSP goes hand in hand. So what exactly are you trying to say? Their methods as DJ Eddie pointed out are like Bose (Their 901 Series) that required the Bose processing module in order to offer a stellar performance. There is nothing wrong with that providing that the user understands without the manufacture’s pre-emphasis in terms of processing, the loudspeaker will not deliver the performance as the manufacture states. Best Regards, |
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Elliot Thompson
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fatfreddiescat
Young Croc Joined: 15 October 2010 Location: N.E.Wales Status: Offline Points: 1083 |
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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 |
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fatfreddiescat
Young Croc Joined: 15 October 2010 Location: N.E.Wales Status: Offline Points: 1083 |
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Link at bottom of page for Powersoft AES Convention paper:
http://www.powersoft-audio.com/en/oem-solutions/ipalmod Edited by fatfreddiescat - 25 May 2017 at 1:02pm |
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circlomanen
New Member Joined: 18 August 2009 Location: sweden Status: Offline Points: 6 |
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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 |
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Ricci
Registered User Joined: 13 March 2017 Location: Louisville, KY Status: Offline Points: 69 |
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We'll just have to disagree on a lot of this. Call it maturity or a mentality or whatever but it is not a negative thing to push the boundaries in any field in my opinion. That is called progress. Just because it does not make sense for you or cannot see the reasons driving the trend does not mean the same holds for everyone else. You are way off base with your comment that only the little guys or inexperienced are looking for maximum output from minimum space and weight. Are B&C, 18Sound, Martin, or Powersoft little companies? This list could go on and on into other audio fields (micro transducers in your phone etc.)...The R&D departments of these companies are the ones putting out the products, patents etc. Their products are engineered the way they are for a reason. Look at the driver and speaker parameters of 70, 50, 30 years back compared with today. Every few years the new product line rolls out and what do they claim? It's lighter, smaller, handles more power, has more excursion, is louder, goes a bit deeper, has lower distortion, etc... Drivers like these are the next generation enabling that. Yes the drivers model slightly different than a traditional driver but that does not mean they cannot be made to have a voltage response every bit as flat in a bandpass or horn alignment. It is not that hard. There are very few modern pro audio subwoofers on the market that have a truly flat response without signal processing. These can be made to work in a standard size vented cab with a high pass, low pass, which are standard anyway and perhaps one band of broad mild EQ. The 21 you keep referencing takes LESS power to produce low bass and has higher maximum low bass headroom on top of that due to the higher xmax. It reproduces low frequencies better not worse.
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