Will this 2 Way LS3/5A Style Speaker Design Work?

[borispm]

As LS3/5A's drivers are out of production long ago, I started searching for modern drivers to make something like a clone of LS3/5A. Here, SEAS drivers are used, in this case 27TDF (H1211) cloth tweeters, CA15RLY(H1216) paper woofer. Can anyone check the crossover to see if it is correct? BTW I used a LR2 @3kHz only to keep the crossover simple and I guess these drivers are up to the task. The cab will be exactly the LS3/5A cab.

A million thanks.

[borispm]

The woofer (CA15RLY)

The Tweeter (27TDF)

[Inductor]

Fs: 35Hz, with limits being 33 and 40Hz

Your Fs is a little more at 44 Hz.
Why do you have "copyed" the xover. The "15Ohm" BBC LS3/5A. Is it the starting point, for you? Objective?
Some use Aurum Cantus AC-130F1 with Fs=35Hz. But Zaph shows test with Fs=50Hz, maybe in a box, investigate his tests/conditions. I didn't check anything else until having more details.
Aurum cantus
Zaph|Audio
https://www.madisound.com/store/prod...oducts_id=8301

[borispm]

First, this crossover is a simple second order passive design suggested by the calculations of WinISD so it is not related to the original BBC LS3/5A.

I wanted to make a compact speaker and the LS3/5A looks like a good one but the sensitivity is too low for my taste so I have give up the original BBC crossover design and of course I may make an external passive bass boost too so that I can use it when I am using more powerful amp and leave it when I'm using T-amp or valve amp.

SEAS drivers are used as they are widely available and are carried by Madisound so it's more convenient for me to buy.

At last, thanks for your advice, I may wanna try the Aurum Cantus next time.

[Inductor]

Originally Posted by borispm

First, this crossover is a simple second order passive design suggested by the calculations of WinISD so it is not related to the original BBC LS3/5A.

I wanted to make a compact speaker and the LS3/5A looks like a good one but the sensitivity is too low for my taste so I have give up the original BBC crossover design and of course I may make an external passive bass boost too so that I can use it when I am using more powerful amp and leave it when I'm using T-amp or valve amp.

SEAS drivers are used as they are widely available and are carried by Madisound so it's more convenient for me to buy.

At last, thanks for your advice, I may wanna try the Aurum Cantus next time.

Good.
SB Acoustics SB15NRXC30-8 5" Woofer (previous post)
This also looks like a good candidate (for the price asked).
Silver Flute W14RC25-08 ohm 5-1/2" Wool Cone
Scan-Speak 15W/8434G00 Discovery, 5.25" Midwoofer

[borispm]

I may need a higher order crossover, hence a more complicated crossover for the Silver Flute to avoid that peak at 8kHz. The SEAS is smooth up to 10kHz so I feel more comfortable to cross it at 3kHz via LR2 but the Silver Flute seems like asking for at least a LR3 or even LR4. The Silver Flute maybe a decent candidate, but I think the 2nd order crossover I designed is complicated for a newbie like me already.

I'm thinking of dropping the Zobel network to save two components for the external bass boost now.

Thanks for your advice again.

[borispm]

The Scanspeak and SB Acoustic woofers have a lower Qts so I'm not sure if they can provide as much bass extension in a sealed cab. The SEAS woven poly cone is in fact more suitable for the application and the t/s parameters are even closer to that of KEF B110 but it's ugly in my opinion.

[Inductor]

Others deserving attention for some simulations are the expensive serious drivers from AudioTechnology - C-Quenze & Flexunits 4 inches types, Sd: 96 cm2, the first one looking better from the point of view of Fs.
Flexunits 4 H 52 06 13
C-Quenze 15 H 52 06 13 SD

[planet10]

If you want a 1st class LS3/5A-size speaker, and keep the XO simple, the Mark Audio Alpair7 fits nicely into a sealed box of that size.

Due to Hoffman's Iron law, a box this size will never be overly efficient (a trade-off between efficiency & bass extension), but with the simple XO (ie none) A7 is more efficient than a real LS3/5A.

A7 is also available in Honk Kong -- if you can, arrange with Mark to pick-up and listen to some of the stuff in his studio.

dave

[borispm]

I'm not expecting anything terribly efficient at all and I have no plans to build a true LS3/5A. Mark's Alpair 7 must be great, but I'm trying to experiment with a two way design and be as close to the original BBC design as possible without messing up with a complicated crossover. So, with a more capable tweeter, I cross it with 2nd order instead of 3rd order, the crossover frequency is still 3kHz, and I may add an external 2 components bass boost at around 120Hz to bring the BBC midbass hump.

BTW, I may find Mark for the CHR70 for my desktop setup later as well.