3-way active loudspeakers (+ sub?)

[noboman]

Hey everyone,

I'd like to build my own stereo 3-way loudspeakers with active x-overs and would be grateful for any advice you could offer.

Now - I have a used pair of accuton C50-8-044 drivers (datasheet here) at home that I want to implement in this project.
spending some time looking for a woofer and tweeter, I found these:
8'' woofer: peerless hds exc 205 (datasheet)
1" dome by human speakers (specs)

I have to admit that I don't have any experience in matching drivers.
my choice is solely based on sensitivity / frequency response and partly on the recommendations of LDSG Introduction.
For the crossovers I got my eyes on Rod Elliot's analog 24 dB/Octave Linkwitz-Riley ones.

My questions now are:
1. Are there any other parameters that should be taken into account for a good match of drivers (i.e. do I have to reconsider my choice)?
2. What crossover frequencies would you recommend? Looking at the FR and the impedance charts I tend to 700Hz and 6kHz.
3. In what enclosures would you put these three drivers?
4. Does it make sense to add a subwoofer at <70Hz? For example this one?

would be glad for any input,
cheers, Lorenz

[Trapshooter]

You might want to read a good book on speaker building first. I'm presently reading "Speaker Building201" from PE myself. If I was to do a three way, I'd start with a solid midrange driver, probably 4", with crossover points at 300 to about 3K and go from there.

[tinitus]

Originally Posted by noboman

Now - I have a used pair of accuton C50-8-044 drivers

Even if you go active it might be worth to study this design from Troels Gravesen

SP44ScanSpeak 18W/

[CharlieLaub]

Have you seen these measurements of an actual Human Pro 002 tweeter?

Human Speakers Pro 002 tweeter

-Charlie

[doug20]

The OP should definitely just copy Troels Gravesen's Accuton build.

Definitely a better Dome choice in using the OW1, the human speakers dome is not nearly as functional as a true tweeter.

[Francec]

Hi Lorenz,
I use the LR crossover (P09) PCBs, for 3 way active speakers, from Rod Elliott and am very happy with result. If you are thinking about using a sub-woofer too, you might want to think about the other LR available from Rod, P125 which is a four way.

My questions now are:
1. Are there any other parameters that should be taken into account for a good match of drivers (i.e. do I have to reconsider my choice)?
2. What crossover frequencies would you recommend? Looking at the FR and the impedance charts I tend to 700Hz and 6kHz.

You should read Rod's article, "Benefits of Bi-Amplification - Not quite magic, but close" Parts I and II, in which he discusses crossover frequencies and that you should try to cover the range from about 300 to 3,000 Hz with one driver to avoid any problems associated with crossing over in the area of greatest human sensitivity.
Zaph Audio has tested drivers that would be very good for that range.

3. In what enclosures would you put these three drivers?

The specifications provided by the manufacturer should give you some guide or you could use WinISD (or ask here. ).

4. Does it make sense to add a subwoofer at <70Hz? For example this one?

I am looking at the same thing at the moment. I would to give your new baby the widest frequency response.

Frank

[noboman]

thanks for all your help. this is an amazing forum!

Even if you go active it might be worth to study this design from Troels Gravesen

SP44ScanSpeak 18W/

these loudspeakers look like a superb solution for me. and quite pretty too ;-)
a little more expensive but at least I don't have to worry so much about enclosure design.

Have you seen these measurements of an actual Human Pro 002 tweeter?

Human Speakers Pro 002 tweeter

oh, this is very helpful - and revealing. they don't seem as good as I thought them to be, at least for the intended range...

You should read Rod's article, "Benefits of Bi-Amplification - Not quite magic, but close" Parts I and II, in which he discusses crossover frequencies and that you should try to cover the range from about 300 to 3,000 Hz with one driver to avoid any problems associated with crossing over in the area of greatest human sensitivity.

that's a good point. but I don't want to let my accuton go to waste, and they are best between 800Hz and 6kHz. I think I just have to take that risk, even if it means tweaking for a long time.

I use the LR crossover (P09) PCBs, for 3 way active speakers, from Rod Elliott and am very happy with result. If you are thinking about using a sub-woofer too, you might want to think about the other LR available from Rod, P125 which is a four way.

great to hear from a successful implementation of these circuits!
and your suggestion touches on a subject I have been pondering for some time: Is it better to use a subwoofer as an addition to the main (3-way-)system, assisting the woofer in the low frequencies where it's inefficient?
Or should I use a 4-way-system that crosses over at around 50-60 Hz and thus cutting out the woofer for the low frequencies?

R. Elliot has really done some nice projects. I like the ELF subwoofer idea he describes on his website. Or does someone know of a better (more efficient?) way of building a small (<80 liters) but low-ranging sub?

Lorenz

[Francec]

Lorenz,
You might want to consider a four way design similar to Lenard Audio's Sarabande's; fully active four way (possibly incorporating Rod Elliot PCBs). Have a good read of his thoughts on drivers to cover the whole audible spectrum.
Lenard Audio - Sarabande


Frank

[kipman725]

one thing to consider with ELF is that distortion is high compared to a physicly larger speaker designed to work at those frequancies.

[noboman]

Originally Posted by Francec

You might want to consider a four way design similar to Lenard Audio's Sarabande's;
Frank

I have. His educational pages are really helpful. But I figured it might be easier (and less space-consuming) building 3-way main speakers plus one sub.

Why are the Hiquphon OW1 and OW2 equally priced, when the first one is 3db less sensitive than the second one?
In an active system the OW2 would make more sense, wouldn't they?