crossover for 2 way speaker project ?

[Accuphasee]

Hello all,

I happen to have enough spare speakers to make 2 way speakers based on Rogers LS3/5A.

For the woofers I'd use peerless SKO-130 12ohm based on KEF B110 speakers and tweeters visaton dt 94 8ohm

The problem comes in crossover design.

I've been thinking to use this website to get a basic crossover design.
2-Way Crossover Designer / Calculator

On this site, there is a option called "Crossover Type"

An externally hosted image should be here but it was not working when we last tested it.

I'm looking for a simple design, nothing too crazy.
Which crosshair type should I use here?
Or should I even use this site at all?

Since these speakers would be based on LS3/5A would it be ok to use 3khz crossover frequency response?

thanks

 

[sreten]

Hi,

Forget about calculators. They are utterly useless and very wrong.

Unfortunately for you if you want anything near approaching LS3/5A's standard
you have a shedload to learn about x/o design and good cabinet building practice.

The Peerless SKO-130 is nothing like the 12 ohm Kef B110, it is not based on it.

Its probably very similar to the Peerless driver used in the Kef Coda 7.

Search on simulating loudspeaker design. 3KHz 4th order LR acoustic
is a good x/o target. Search and understand baffle step and fixing it.

rgds, sreten.

 

[Accuphasee]

Hi,

Forget about calculators. They are utterly useless and very wrong.

Unfortunately for you if you want anything near approaching LS3/5A's standard
you have a shedload to learn about x/o design and good cabinet building practice.

The Peerless SKO-130 is nothing like the 12 ohm Kef B110, it is not based on it.

Its probably very similar to the Peerless driver used in the Kef Coda 7.

Search on simulating loudspeaker design. 3KHz 4th order LR acoustic
is a good x/o target. Search and understand baffle step and fixing it.

rgds, sreten.

Hi sreten,

I remember you giving me advice on center speaker build thread I started almost two years ago.
You said exactly the same thing about SKO-130s you said now, that they are completely different from KEF B110, apart from looking the same.

You also said that it would be a very hard task to do, so I gave up from that project.

Now that I have tweeters and woofers which I have no use from a long time now, I thought why wouldn't I attempt to build speakers for desktop pc?

There must be something I could do to build this!

cabinet isnt a problem, I'll build it to LS3/5A specs, that's if I solve the crossover problem 😡

 

[PeteMcK]

re:'cabinet isnt a problem, I'll build it to LS3/5A specs,' - wrong approach, you need to build it to suit the drivers you have. Post links to the spec sheets of those drivers & you might get some sensible suggestions

 

[Lojzek]

I'll make a simulated XO filter if you can find the
datasheet with 2 pi measurement and impedance plot
of your Peerless India driver.

 

[AllenB]

so I gave up from that project.

Do it anyway. This speaker can serve as part of the learning process. 😉

 

[PeteMcK]

Driver data: http://www.audiolabga.com/pdf/SKO130-4.PDF
Edit: Sorry, that the wrong impedance... still looking..
... found the 8 ohm version, (http://www.audiolabga.com/pdf/PEERLESS_INDIA.pdf),
but I think you're going to have to measure the impedance for yourself.
tweeter: DT 94 - 8 Ohm

Xover probably will be quite simple, once you have accurate data, probably a simple 2nd-order LR at ~ 4KHz
contrary to 'Forget about calculators. They are utterly useless and very wrong' - they're OK if you have good impedance data

 

[Accuphasee]

Driver data: http://www.audiolabga.com/pdf/SKO130-4.PDF
Edit: Sorry, that the wrong impedance... still looking..
... found the 8 ohm version, (http://www.audiolabga.com/pdf/PEERLESS_INDIA.pdf),
but I think you're going to have to measure the impedance for yourself.
tweeter: DT 94 - 8 Ohm

Xover probably will be quite simple, once you have accurate data

Yes I made there mistake too, that is 4ohm. I got the datasheet with these speakers when I bought them. Unfortunately, this was 4-5 years ago and I lost it. I sent an email to the seller (willys-hifi) , asked him if has the datasheet, once he replies I'll let you know, in the meantime, I'll keep searching for datasheet online.

 

[Accuphasee]

Alright guys!

I found the 12ohm datasheet online! 😀

here it is!

If you want to download I've made a pdf: https://www.dropbox.com/s/7mwheqry4lif86s/peerless-sko-130b110-clone-12-ohmspairbrand-new.pdf?dl=0

 

[PeteMcK]

Using Unibox, a 12L cabinet tuned to 50 Hz will give an F3 of 50Hz, about as low as you can get out of this driver. If you want to hump it up like the LS3/5 then tune it to 57Hz, but then your F3 will be ~53Hz

8L sealed like the LS3/5a will give an F3 higher than 130Hz....

 

[PeteMcK]

Q&D Crossover: Choosing 3KHz as the xover freq, Zw is ~9 ohms & Zt ~ 8 ohms at that frequency. Plugging these values into this calculator: ERSE - Crossover Calculators
For 2nd order LR you’ll get ~ 1mH & 3uF for the woofer LPF, and 3uF & .85mH for the tweeter HPF.
However, because we’re a bit close to the tweeter Fs, for power handling & phase matching I’d up the HPF to 3rd order: 4.4uF, .32mH, 13.3uF, tweeter connected reverse polarity.
For inductors use the nearest preferred value of ferrite cored, & bipolar electrolytics for the caps. (anything else is wasted on these drivers)
This doesn’t take into account any baffle step, which would require a bigger inductor on the woofer & an L-pad on the tweeter to match levels.

 

[Lojzek]

Accu,

by the impedance of your driver, one can only assume that someone
has messed with the figures to make it look like 12 ohm speaker unit
which apparently isn't. The font of the letters is obviously smaller than
original data. No way a 12 ohm unit would have 90 dB of spl half space.

edit: a 10 ohm version with 85 dB
http://www.peerlessaudio.com/prod_details.asp?id=104

 

[system7]

All a bit weird for the Peerless WKO-130! 😀

Very wobbly data. How did that happen?

Seems to me it's quite a well behaved 4 ohm 5" paper woofer. Nothing to do with 12 ohms.

Anybody want to sim it?

I get a guesstimate crossover a bit like the last image in 12L reflex. Be interested what you find. 🙂

 

[Accuphasee]

So the data is invalid? 🙁

anyway, 12 ohm is stamped on the driver

I measured these drivers with a cheap multimeter, and after some reading I got this. On one speaker I got 10.5ohms and on other 10.6ohm 😕

So perhaps these are 10ohm drivers?

Weird? 🙄

 

[Accuphasee]

There was an ad for these speakers. Seller was selling them as "Peerless SKO 130(Kef B110 clone) 10 Ohms,pair,brand new"
http://www.canuckaudiomart.com/details/649147116-peerless-sko-130b110-clone-12-ohmspairbrand-new/

But on pictures he uploaded, it was stamped 12 ohm on the drivers, same as mine.

That's where I got the datasheet from.

 

[Lojzek]

Drivers are indeed 12 ohms with Re=10,5 but the datasheet is for a
4 ohm unit with numbers modified as already said. I suggest you download
this: ARTA Download and measure the impedance yourself. We could
guesstimate the spl curve of the Peerless being somewhat similar to 4 ohm
version with a reference level being somewhat lower than 85 dB. If you're
confident enough, you should measure SPL too. Read ARTA manuals.

 

[Lojzek]

...contrary to 'Forget about calculators. They are utterly useless and
very wrong' - they're OK if you have good impedance data

Sreten is right, bearing in mind the typical newbie approach to using
online calculators and that is I have an 8 ohm bassmid so I have to punch
an eighter in the calculator and I'm good. They have probably never heard
baffle step term either.

 

[PeteMcK]

... as with any tool, it's effectiveness depends on the skill of the user....