ACE Bass design...

[Boscoe]

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

[wakibaki]

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

[Zero D]

@ 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 - ACE-bass amplifier design

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

[chris661]

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

[UrSv]

It is legal as the holder of the patent are the ones making that particular sub Not to mention the fact that it's very old. Audio Pro are still making ACE-Bass subs in volume. Yamaha also used the same solutions, licensed or bought from Audio Pro, although they called it YST.

[tvi]

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

[Richard Ellis]

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.........

[Boscoe]

Originally Posted by Richard Ellis

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.........

How do i run these numbers?

[bjorno]

Originally Posted by Boscoe

How do i run these numbers?

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/...0by%20step.pdf