Okay so I want to cheat on enclosure design!
I wanted to know how to calculate the new parameters for my driver the Eminence Delta 12LFA and then how to calculate the components to be used in the amplifier design. I would like to use an LM3886 amp if that's possible. I have a 42l enclosure kicking around if I could use that it would be great.
Thanks
Boscoe
I wanted to know how to calculate the new parameters for my driver the Eminence Delta 12LFA and then how to calculate the components to be used in the amplifier design. I would like to use an LM3886 amp if that's possible. I have a 42l enclosure kicking around if I could use that it would be great.
Thanks
Boscoe
The Eminence website shows the TS parameters for this driver, WinISD Pro (free download) has modelling for the Delta 12LF, which is probably the same driver, or not that different, or you can re-enter the parameters, it will show you the response you can expect for a variety of configurations. Follow the directions as you enter the parameters, the help will keep you on track if there are any discrepancies. You can use an LM3886, but it will be a bit underpowered in this app. at ~50W into 8 ohms, the driver is rated 500.
There's not much to design as far as the amp is concerned, just follow the datasheet (read it thoroughly) and set the LF cutoffs to accommodate a bit below 40Hz. Build it dual-rail and don't omit any of the optional components if you go this route and make sure the heatsinking is more than adequate. It really is a bit weak in this application though.
w
There's not much to design as far as the amp is concerned, just follow the datasheet (read it thoroughly) and set the LF cutoffs to accommodate a bit below 40Hz. Build it dual-rail and don't omit any of the optional components if you go this route and make sure the heatsinking is more than adequate. It really is a bit weak in this application though.
w
@ Boscoe
Hi
I have a feeling that what you'ld like to do is try and replicate Karl-Erik Ståhl's ACE bass, that he invented/patented in the 1970's ? It's a very ingenius design, that not many people seem to know about ! I remember reading articles on it, & then the patent. It's still manufactured
ACE bass home - Audio Pro - Sound of Scandinavia
It uses Positive feedback to get negative resistance which electronically alters the T/S parameters of the driver, and thereby is able to produce very low f3 in a small box = genius
There is a thread on here which you might be interested in.
ACE-bass amplifier design - http://www.diyaudio.com/forums/subwoofers/104447-ace-bass-amplifier-design.html
One on sale here for ONLY £100.
Choice Hi-fi price: - Choice Hi-fi UK - High End Audio Equipment - SubWoofers - Audio Pro - B2-40 Ace-Bass Subwoofer
Hi
I have a feeling that what you'ld like to do is try and replicate Karl-Erik Ståhl's ACE bass, that he invented/patented in the 1970's ? It's a very ingenius design, that not many people seem to know about ! I remember reading articles on it, & then the patent. It's still manufactured
ACE bass home - Audio Pro - Sound of Scandinavia
It uses Positive feedback to get negative resistance which electronically alters the T/S parameters of the driver, and thereby is able to produce very low f3 in a small box = genius
There is a thread on here which you might be interested in.
ACE-bass amplifier design - http://www.diyaudio.com/forums/subwoofers/104447-ace-bass-amplifier-design.html
One on sale here for ONLY £100.
Choice Hi-fi price: - Choice Hi-fi UK - High End Audio Equipment - SubWoofers - Audio Pro - B2-40 Ace-Bass Subwoofer
As a patented system, is that last product listed actually legal? If they could, I'd expect every HTIB manufacturer to be using ACEbass, but they don't.
The link to ACE-bass amplifier design is the right one - it has the circuit diagrams and formulae for the values of the various components needed.
What you need to do is to play with the T/S parameters of the driver until the driver sims well in 40L (accounting for volume lost by driver insertion), tuned low.
Think high Mms, Qts of ~0.3 and low Fs.
Chris
The link to ACE-bass amplifier design is the right one - it has the circuit diagrams and formulae for the values of the various components needed.
What you need to do is to play with the T/S parameters of the driver until the driver sims well in 40L (accounting for volume lost by driver insertion), tuned low.
Think high Mms, Qts of ~0.3 and low Fs.
Chris
Yamaha's YST is covered by these and various ancillary patents
US 5206912 Power amplifier adapter
Temperature compensation circuit for negative impedance driving apparatus
If you search Yamaha and Masao Noro (ex-Stax designer) you can find quite a few.
rgds
James
US 5206912 Power amplifier adapter
Temperature compensation circuit for negative impedance driving apparatus
If you search Yamaha and Masao Noro (ex-Stax designer) you can find quite a few.
rgds
James
Attachments
Running the numbers for a sealed system, I get 1.9 cubic foot enclosure@ .707 Qtc.
Pushing it a little to Qtc of .8 I get right at your available box volume....stuff the box with Dacron...& your right on the money.
With an Fs of 51 Hertz it won't get THAT low down.
___________________________________________________Rick.........
Pushing it a little to Qtc of .8 I get right at your available box volume....stuff the box with Dacron...& your right on the money.
With an Fs of 51 Hertz it won't get THAT low down.
___________________________________________________Rick.........
Hi Boscoe,
Dont
I've tested for the first time Baldins ACE-Bass .xls program using your driver: The submitted picture..
One problem : Couldn't change the RRs value in order to make the effective Re lower
If a very mild ACE-bass correction is executed the program was useful to fit the driver well with your 42L box but of course you can tweak further if you accepts the SPL loss that would be counteracted if a positive feedback could be provided by using the RRs value to change effective driver Re.
Suggestion:Contact Baldin: Ask for the .xls to be updated..
b
Baldin's Blog
http://www.sensibleaudio.dk/AceBass/AceBass TS Parameters - Peerless 6.5 Inch.xls
http://www.sensibleaudio.dk/AceBass/AceBass calculation sheet step by step.pdf
Attachments
Info
Good morning. I would like to implement ACE Bass, would it be possible, if it's not too much trouble, that you send me some documentation?
my mailbox is: luciano.veneziano@gmail.com.
this PDF would also be useful to me.
Page not found – SensibleAudio
Great things
Hi Boscoe,
Dont
I've tested for the first time Baldins ACE-Bass .xls program using your driver: The submitted picture..
One problem : Couldn't change the RRs value in order to make the effective Re lower
If a very mild ACE-bass correction is executed the program was useful to fit the driver well with your 42L box but of course you can tweak further if you accepts the SPL loss that would be counteracted if a positive feedback could be provided by using the RRs value to change effective driver Re.
Suggestion:Contact Baldin: Ask for the .xls to be updated..
b
Baldin's Blog
Page not found – SensibleAudio TS Parameters - Peerless 6.5 Inch.xls
Page not found – SensibleAudio
Good morning. I would like to implement ACE Bass, would it be possible, if it's not too much trouble, that you send me some documentation?
my mailbox is: luciano.veneziano@gmail.com.
this PDF would also be useful to me.
Page not found – SensibleAudio
Great things
As an old friend of Bell, I can see that - just like Bell telephone circuits - the ACE stuff is drawn so nobody can make sense of it.
If you can make your own amp, then here is all you need to know:
put a half-Ohm resistor in series with the speaker and with one end at ground. That's your feedback signal. All the rest is self-evident.
B.
If you can make your own amp, then here is all you need to know:
put a half-Ohm resistor in series with the speaker and with one end at ground. That's your feedback signal. All the rest is self-evident.
B.
What bentoronto writes has quite some truth in it.
The core of all these more or less complicated circuits is the resistor (usually around 0.4 Ohm) that generates the signal similar to the cone movement.
You can simply feed it back into the amp and have your MFB. Nothing complicated needed.
Most patents, even some filed only a few years ago, try to downplay this major principle, what makes them questionable.
All additional decoration is only there to solve some problems that come along with this simple basic principle, discovered decades ago:
1. you need to filter the signal, so that DC is removed.
2. the frequency response has to be limited to maybe 100 Hz.
3. you have to address the changing working points and temperature depended parameters of driver and electronics.
4. The aim is to make it somehow self adjusting, as any feed back can easily start to oscillate. No one wants to adjust something today, on a regular base!
So, nothing new at all, basic electronics design.
That is nothing worth of a patent, but only use of plain vanilla, like filters, known for decades.
To solve these secondary problems, you can add discrete circuits or integrated ones, simple or complicated. All this is based on common knowledge of electronics.
In the the true and honest sense of patent law (and Ben's and my opinion), absolutely nothing worth to become a patent.
Think of creating a new letter between "A" and "B" and claiming a patent for any use of the whole alphabet worldwide.
Patents have quite some problems today. Manly Chinese actors have established a business model of patenting well known, stone old, common basics with fancy new descriptions and sue producers for using them in existing products. Because courts need years to reject such claims (try to win in a Chinese court, as an American...) while sales of finished products are stopped, you have to settle with such criminals. China sees this as legitimate use of law...
That is why such newly patented antiques make some sensible people angry.
The core of all these more or less complicated circuits is the resistor (usually around 0.4 Ohm) that generates the signal similar to the cone movement.
You can simply feed it back into the amp and have your MFB. Nothing complicated needed.
Most patents, even some filed only a few years ago, try to downplay this major principle, what makes them questionable.
All additional decoration is only there to solve some problems that come along with this simple basic principle, discovered decades ago:
1. you need to filter the signal, so that DC is removed.
2. the frequency response has to be limited to maybe 100 Hz.
3. you have to address the changing working points and temperature depended parameters of driver and electronics.
4. The aim is to make it somehow self adjusting, as any feed back can easily start to oscillate. No one wants to adjust something today, on a regular base!
So, nothing new at all, basic electronics design.
That is nothing worth of a patent, but only use of plain vanilla, like filters, known for decades.
To solve these secondary problems, you can add discrete circuits or integrated ones, simple or complicated. All this is based on common knowledge of electronics.
In the the true and honest sense of patent law (and Ben's and my opinion), absolutely nothing worth to become a patent.
Think of creating a new letter between "A" and "B" and claiming a patent for any use of the whole alphabet worldwide.
Patents have quite some problems today. Manly Chinese actors have established a business model of patenting well known, stone old, common basics with fancy new descriptions and sue producers for using them in existing products. Because courts need years to reject such claims (try to win in a Chinese court, as an American...) while sales of finished products are stopped, you have to settle with such criminals. China sees this as legitimate use of law...
That is why such newly patented antiques make some sensible people angry.
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Well, ACE-Bass is a bit more than just MFB. It's also; negative output impedance and a circuits that makes it possible to "control" the physical characteristics of the drivers (like making the cone behave as if it was considerable heavier than it really is).
Or maybe that's the same thing?
ACE-Bass also relies on 2 drivers (at least) where one is turned to move the opposite direction in order to cancel out 2:nd order distorsion.
//
Or maybe that's the same thing?
ACE-Bass also relies on 2 drivers (at least) where one is turned to move the opposite direction in order to cancel out 2:nd order distorsion.
//
There is no need or requirement for two drivers in ACE-BASS. Stahl just happened to use two in the system described in his JAES paper. Maybe he needed or wanted more output from the puny drivers he used (6.5" driver for a 20Hz subwoofer!). But they do have the benefit of mostly cancelling even order distortion products when placed close to each other with one mounted "backwards".
Well, ACE-Bass is a bit more than just MFB. It's also; negative output impedance and a circuits that makes it possible to "control" the physical characteristics of the drivers (like making the cone behave as if it was considerable heavier than it really is).
Or maybe that's the same thing?
You're absolutely right the second time: tautology.
Think about it. When the speaker impedance rises due to cone motion showing up as back-EMF, the amp pumps less power to it. Now THAT is negative output, meaning a virtual negative output impedance hidden inside your amp.
As Turbowatch2 intelligently notes, once you have speaker feedback, the rest is fine-tuning.
B.
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I join with CharlieLaub in applauding the wisdom of Turbowatch2's post.
(OK next time, I'll find something mean to say.)
B.