High Sensitivity Design

Rick Craig · « **on:** 20 Jan 2010, 05:19 pm »

Woofer from Acoustic Elegance and a special ribbon tweeter.

Ok - I was asked for more details so here's a modified post. This has actually been in the works for quite awhile. A Texas customer contacted me and asked about doing a custom design focused on high sensitivity and friendly to a low wattage tube amp. We discussed various formats and drivers, including line arrays. With the ribbon we selected a line array was going to be extremely expensive so we looked at alternative designs. The problem is that many high sensitivity drivers are lacking in terms of coloration, poor bass extension, and cone/motor assemblies that have enough resolution to integrate well with a ribbon tweeter.

We'll see how well the AE woofer performs. I've already tested the ribbon and it's exceptionally good.

chrismercurio · « **Reply #1 on:** 21 Jan 2010, 05:29 am »

I can't wait for the full report.

Kars · « **Reply #2 on:** 21 Jan 2010, 05:58 pm »

Can't wait either!

jtwrace · « **Reply #3 on:** 21 Jan 2010, 06:00 pm »

which ribbon are using?

Rick Craig · « **Reply #4 on:** 21 Jan 2010, 06:57 pm »

Quote from: jtwrace on 21 Jan 2010, 06:00 pm

which ribbon are using?

Can't say right now but once the project is finished I'll post the details.

Zero the Hero · « **Reply #5 on:** 23 Jan 2010, 07:01 pm »

can you tell us what size woofer?

Rick Craig · « **Reply #6 on:** 23 Jan 2010, 07:10 pm »

Quote from: Zero the Hero on 23 Jan 2010, 07:01 pm

can you tell us what size woofer?

The TD15M 15" driver. The emphasis is on sensitivity so that's why this version was chosen.

satfrat · « **Reply #7 on:** 23 Jan 2010, 07:15 pm »

Is this design going to be a floorstander or a monitor Rick? Thanks.

Cheers,
Robin

Rick Craig · « **Reply #8 on:** 23 Jan 2010, 07:37 pm »

Quote from: satfrat on 23 Jan 2010, 07:15 pm

Is this design going to be a floorstander or a monitor Rick? Thanks.

Cheers,
Robin

Floorstander design. A monitor wouldn't be practical because the woofer needs a large cabinet volume, especially if running it ported. Looking at the woofer I remembered working with the same driver when it was called the Lambda 15. I had a guy bring a DIY cabinet with one of the woofers and the Danley horn with if I remember correctly 4-6 cone drivers firing into the horn. Ugh - resonance city with that horn.

JoshK · « **Reply #9 on:** 24 Jan 2010, 04:17 am »

FYI, that design was called the Unity.

P.S. isn't it hard to cross a 15" to a ribbon and not muck up the directivity at the XO region?

chrismercurio · « **Reply #10 on:** 24 Jan 2010, 05:16 am »

I'm sure Rick can handle it within it's limitations. He did wonders with my GPALTEC's.

richidoo · « **Reply #11 on:** 25 Jan 2010, 12:48 am »

The AE woofer is extremely low inductance, so it plays very linearly up to 2kHz according to AE website. Somewhere I saw a pic of control room monitor using similar arrangement.

I can't wait to hear this one.

Rick Craig · « **Reply #12 on:** 25 Jan 2010, 03:29 pm »

Quote from: JoshK on 24 Jan 2010, 04:17 am

FYI, that design was called the Unity.

P.S. isn't it hard to cross a 15" to a ribbon and not muck up the directivity at the XO region?

Right, it was the Unity horn. This ribbon can cross really low so that helps but yes it's a challenge.

Rick Craig · « **Reply #13 on:** 2 Feb 2010, 10:46 pm »

Checked the woofer's sealed box performance with a nearfield curve. -3db @60hz and -10db @40hz so this would be ideal for adding a powered subwoofer. Next will be the response and sensitivity tests. Fs was spot on.

X5nut44 · « **Reply #14 on:** 7 Feb 2010, 04:51 am »

Quote from: Rick Craig on 2 Feb 2010, 10:46 pm

Checked the woofer's sealed box performance with a nearfield curve. -3db @60hz and -10db @40hz so this would be ideal for adding a powered subwoofer. Next will be the response and sensitivity tests. Fs was spot on.

I will be following this project closely. We’ve discussed doing something like this before but I have been sitting on the fence but now I may be getting off. How well will the 15-inch woofer work in a ported enclosure? Is it possible to get -3db @ 40 Hz? I know the enclosure will be much larger but I’m trying to stay away from using a subwoofer.

Rick Craig · « **Reply #15 on:** 8 Feb 2010, 03:09 pm »

Quote from: X5nut44 on 7 Feb 2010, 04:51 am

I will be following this project closely. We’ve discussed doing something like this before but I have been sitting on the fence but now I may be getting off. How well will the 15-inch woofer work in a ported enclosure? Is it possible to get -3db @ 40 Hz? I know the enclosure will be much larger but I’m trying to stay away from using a subwoofer.

Probably closer to 50-55hz depending on the tuning of a ported enclosure. The fs of the woofer is 33hz so you'll still have decent extension below the -3db point.

lokie · « **Reply #16 on:** 8 Feb 2010, 03:35 pm »

What do you have in mind for the mid- registers? Any chance you will explore compressions drivers?

I'll be watching this thread closely.

Rick Craig · « **Reply #17 on:** 8 Feb 2010, 03:55 pm »

Quote from: lokie on 8 Feb 2010, 03:35 pm

What do you have in mind for the mid- registers? Any chance you will explore compressions drivers?

I'll be watching this thread closely.

The woofer is designed to work in a 2-way so no additional mid is needed.

Rick Craig · « **Reply #18 on:** 8 Feb 2010, 06:51 pm »

Response curves look good for the woofer. Sensitivity is 96.5db which is in line with what I expected. With the normal amount of crossover compensation to flatten out the upper midrange a system sensitivity of 93-94db is possible.

lokie · « **Reply #19 on:** 8 Feb 2010, 06:58 pm »

[quoteResponse curves look good for the woofer. Sensitivity is 96.5db which is in line with what I expected. With the normal amount of crossover compensation to flatten out the upper midrange a system sensitivity of 93-94db is possible.][/quote]

What would the impedance window look like?