Using an LS 3/5A Cabinet with non-LS 3/5A Design

[system7]

I've been having a look at the Fountek FRS135EX equalisation idea.
https://www.madisoundspeakerstore.com/approx-5-fullrange/fountek-fr135ex-5-full-range/

The direct link to the PDF for 420X180 mm baffle is here:
http://www.madisound.com/pdf/FR135EX-Encl.pdf

Electrically it's a notch at 1.4kHz and 10kHz. The 1.4kHz peak is a baffle and surround issue that most 5" speakers, including the LS3/5A, have. The 10kHz peak is a cone breakup issue from the metal driver. The driver is about Le 0.6mH which is higher than most fullrangers. More your typical 5" woofer.

There's just so many ways to skin a cat in speakers, but I think you treat it as a normal metal driver. Still looks like second order 3.5kHz crossover bass with the 1.4kHz notch is best to me.

SEAS 5INCH
Fostex FE126E +

You can tell I am still playing with ideas here. 😱

 

[DDF]

Thanks System-7. But the problem is I have to use my LS3/5A cabinet. And I prefer to use it unmodified. That means most of the TB drivers can't be used.
Tang Band W5-1611SAF comes close when it comes to the Cabinet volume I have. But the driver is too big to fit the baffle. This Fountek at least on paper looks good with the LS 3/5A box and baffle I have.

Will the W4-1720 fit the baffle? Its a very nice little driver. My understanding from
LS3/5A Support
is that the LS3/5A is about 5 litres.

My drivers measured

SN 103
59.776 "Fs Hz"
3.900 "Re Ohms"
17.782 "Res Ohms"
2.454 "Qms "
0.538 "Qes "
0.441 "Qts "
0.142 "L1 mH"
1.111 "L2 mH"
1.742 "R2 Ohms"
0.218 "RMSE-load Ohms"
57.00 "Area (Sd)"
3.430 "Vas liters"
9.431 "Mms(Sd) grams"
751.665 "Cms(Sd) æM/Newton"
5.066 "Bl(Sd) Tesla-M"
83.167 "SPLref dB "
0.313 "Rub-index "

You'd get a Q of 0.65 and F3 of 85Hz in a 4.5L box (assuming here components and drivers take up some box space). It may be a bit tame in the bass but the xover could help with that.

When I redid my JR149s, I looked for a replacement woofer for the Kef B110s (same family as used in LS3/5As), and the choices were slim at the time but a Eruo supplier email to me at one time: "SPH135/AD is our standard B110 replacement"

Another choice in a similar frame size is Monacor's SPH135/C carbon. It would probably work well in that cabinet size and give you a bit more bass but I hear it is tricky to crossover (peak at 6.5k, and needs early cut off). Challenge would be getting measurements to design an xover with. The SPH135KEP is supposedly a bit easier to tame, and another option.

I've also heard good things about the Arum Cantus AC-130F1, it may fit the baffle and box size.

Dave

 

[system7]

It's a feature of the LS3/5A cabinet that the front baffle is removable. Having seen so many threads of agonising over a substitute for the 5" KEF woofer, my inclination would be to cut a new baffle from some builders ply.

A 4" driver looks much better for a 5L box anyway:
Piccolata Mini Monitor
Tang Band W4-1720 4" Underhung Midbass Driver

Just one of many interesting small designs. I wouldn't think changing the tweeter to whatever you fancy is a big deal. But it's 104mm in the LS3/5A.

 

[Ronj]

No worries about the oscilloscope since someone else took it. I waited until the cows came home for you to pick it up. 😛

It it was me, I'd use both the Dayton and the Fountek and cross them over pretty low; sub 300Hz. However, you may need to rehouse either of the drivers. But that's my option.

And no, you don't get to feel my foot on your derriere if you drop by my place next. 😀

I'll probably post some pix on Xtremeplace once my cabinets are done.

Are you instigating me towards a LS 3/5A/AB1 type solution? As in using Dayton Audio DC130AS-8 as a ported Bass driver in a separate cabinet, cut off at 300Hz and let the Fountek take over from there? But with a provision of running Fountek 2-way fullrange like in AB1 case?

I think that would be a mammoth effort! Wouldn't it?

 

[DIYer Straits]

Are you instigating me towards a LS 3/5A/AB1 type solution? As in using Dayton Audio DC130AS-8 as a ported Bass driver in a separate cabinet, cut off at 300Hz and let the Fountek take over from there? But with a provision of running Fountek 2-way fullrange like in AB1 case?

I think that would be a mammoth effort! Wouldn't it?

Yes, something like that. You remove the bass duties from the FR135 and it can go louder with lower distortion. You will still need to put a crossover in but it will still be a simple first order.

All the corrections, if any, will be on the Fountek's frequency response.

So you have 3 choices, either a single-driver full range, an assisted full range or a 2-way.

I'd go for the 2-way.

 

[Ronj]

Yes, something like that. You remove the bass duties from the FR135 and it can go louder with lower distortion. You will still need to put a crossover in but it will still be a simple first order.

All the corrections, if any, will be on the Fountek's frequency response.

So you have 3 choices, either a single-driver full range, an assisted full range or a 2-way.

I'd go for the 2-way.

That's something I can actively consider. In that case, I would still want Fountek + SEAS to be a proper 2-way(just like in the case of LS 3/5A) and perhaps with no mid-bass hump like in the case of LS3/5A that way I can easily integrate with bass module. But the unit shall be usable with out bass-module when needed as well..

But that means a huge design challenge?

Because I shall be able to use 2 pairs of 5-way binding posts on the bass model, where one pair works as output to the 2-way LS3/5A Box. And the lower crossover and a first order capacitor(for limiting lows to the Fountek Driver) can be kept in the bass-box... Then it becomes like LS3/5A + AB1

 

[system7]

You're floundering away here, Ronj. You haven't got a point of departure, you see! 😀

You don't have even a start...😱

Here's the SEAS 27TDFC soft dome tweeter, for our reference.
H1189-06 27TDFC

Fountek FR135EX woofer:
https://www.madisoundspeakerstore.com/approx-5-fullrange/fountek-fr135ex-5-full-range/

Now here's the KEF CS1 in a similar sort of box.
Explore KEF - Constructor Series CS1 to CS9, PL301 - KEF United Kingdom

I think you'll end up with something like the below. A notched second order bass, and just your regular sort of third order tweeter. You won't be using the 1.2kHz 220R/0.33uF "acoustic butterworth" tweeter notch though. That's specific to the T27 Fs of 1.2kHz. You'll also probably take the bass notch up a bit to 1.4kHz if we trust Fountek with their 180mm baffle width, but it depends on the baffle too. Hard to say, given I haven't modelled it yet.

And just to prove there's many ways to skin a cat, here's the rather different Keesonic Kub.

 

[Ronj]

You're floundering away here, Ronj. You haven't got a point of departure, you see! 😀

You don't have even a start...😱

Here's the SEAS 27TDFC soft dome tweeter, for our reference.
H1189-06 27TDFC

Fountek FR135EX woofer:
https://www.madisoundspeakerstore.com/approx-5-fullrange/fountek-fr135ex-5-full-range/

Now here's the KEF CS1 in a similar sort of box.
Explore KEF - Constructor Series CS1 to CS9, PL301 - KEF United Kingdom

I think you'll end up with something like the below. A notched second order bass, and just your regular sort of third order tweeter. You won't be using the 1.2kHz 220R/0.33uF "acoustic butterworth" tweeter notch though. That's specific to the T27 Fs of 1.2kHz. You'll also probably take the bass notch up a bit to 1.4kHz if we trust Fountek with their 180mm baffle width, but it depends on the baffle too. Hard to say, given I haven't modelled it yet.

And just to prove there's many ways to skin a cat, here's the rather different Keesonic Kub.

Yeah I can see what you are pointing me towards. But Fountek being a fullranger, I thought a bit more simplistic crossover than what is requires for the infamous b110. I think I was just over-optimistic.

 

[nimo_jon]

Yeah I can see what you are pointing me towards. But Fountek being a fullranger, I thought a bit more simplistic crossover than what is requires for the infamous b110. I think I was just over-optimistic.

Hi Roni did you managed to do a Fountek. I am going that path soon, but using MiniDSP in place of passive crossover.