Classic 3 Way Hi-Fi Speakers

[LafeEric]

Hi there! Though I have been reading here for some time, this is my first thread, and will be my first real speaker project. I look forward to your thoughts and suggestions as things progress.

As the title suggests I am looking to build some classic big box 3 way speakers. I like a fairly big sound (though it may not be so big to some of you) and while I would probably be very happy with a pair of Klipsch Horns or La Scalas, I just can't afford that - so a good alternative for me is to build my own.

The design criteria for these speakers I have decided are thus:

* 3 way design, utilizing a woofer, mid, and tweeter.
* Passive crossover with minimal insertion loss
* Fairly high efficiency (92~95 db)
* Fairly high power handling (~200 watts)
* Fairly high max SPL (~120 db)
* Fairly flat frequency response (+-3db)
* As close to 20-20KHz as I can realistically get, holding within other parameters
* Fairly low distortion
* Attractive cabinet (WAF!)

As the 'realistically' and all the 'fairly's' suggest I have no intention of being fanatical about any of it, but I do want to give it a good effort and build some speakers I can enjoy listening to and looking at for a long time.

Of course I have been considering this for a long time and have already done a lot of comparisons and so have chosen and acquired the drivers.

For the woofers I have acquired a set of JBL 2226H. These will require a fairly large cabinet, but as I kind of had in mind something rather imposing anyway, I'm quite happy with that.

For the tweeters I bought a pair of the venerable Selenium D220Ti, mated to Selenium HC23-25 horns. These seem to have a very good reputation, very clear, not harsh, with low distortion.

For the mids I have chosen a pair of B&C 6MD38. These should fill in the gap nicely between the 2226H's and the D220Ti's, giving the latter some breathing room for higher power handling.

I'll continue to post as things progress.

[lowpoke]

So you're leaving it at that for the first post? Aw c'mon, at least show us a cabinet design or something! ...
or how about a shot of all those brand new drivers laid out on the floor. You can't just leave it to our imaginations.

[sreten]

Hi,

3 way speakers are notoriously difficult to design properly.
The "classic" method is to select 3 drivers and sling them together.
It usually doesn't work very well because too much is ignored.
You need a high quality methodology to get a high quality result.

The links below contain a wealth of information.
Troels has quite a lot of info on JBL drivers.
Zaph has measurements of your midrange.

rgds, sreten.

undefinition (see FAQs)
Zaph|Audio
FRD Consortium tools guide
RJB Audio Projects
Speaker Design Works
HTGuide Forum - A Guide to HTguide.com Completed Speaker Designs.
Humble Homemade Hifi
DIY Loudspeaker Projects Troels Gravesen
Quarter Wavelength Loudspeaker Design
The Frugal-Horns Site -- High Performance, Low Cost DIY Horn Designs
Linkwitz Lab - Loudspeaker Design
Music and Design

[adason]

nice list sreten

[LafeEric]

Thanks guys. I appreciate it.

Lowpoke I'll be sure to have plenty of pictures up as I go. I'm sure to have some posts about the drivers pretty quick - I just bought a WT3 and will be posting the measurements I get. The cabinet I only have a vague idea of because there are just too many variables at this point.

Thanks for the links Sreten! Some of those I've seen before but most I haven't and a couple are exactly what I've been thinking I need! As many questions as I have about the cabinet, I'm pretty much dreading trying to figure out the crossover.

But anywho, when in doubt, onwards and upwards!, I always say.

[tinitus]

Originally Posted by LafeEric

I'm pretty much dreading trying to figure out the crossover.

btw, I just recently finished this low budget 4way
different approach
but I rarely play loud
and if I do, its really not very loud
funny thing
when my sister comes visiting she always says; why do you play so loud
and thats when its not loud

well, what is realistic SPL
at a disco ?
or an intimate concert ?
is it a blasting trumpet ?
a jazz singer ?
rock concert ?

[tinitus]

if your max SPL goal really is 120db as you suggets, maybe better go active

hard to avoid increased distortion at loud SPL
even if very very small, its still audible
less clean you might say
even if driver do not distort, the ultimate exstreme precision and control suffers
you might get disco sound rather than smooth hifi

[adason]

tinitus, are you sure that midrange could not use cap to band pass it?

[tinitus]

Originally Posted by adason

tinitus, are you sure that midrange could not use cap to band pass it?

yeah, I know
mid moves too much when loud
but those big caps are bloddy expencive

but if I wanted to play loud, yes it should have a series cap, and a paralel inductor
and it will probably screw up the present filter

but yeah, I have some bipolars I have to try
and a zobel on woofer
but I'm sure it will cause a lot of trouble

I will try it when I have some free time
but right now I just enjoy the music
but to be honest, I'm done with audiophile listening
instead the music is pounding many many hours every day

[LafeEric]

Thanks for the suggestion Tinitus.

I may well build an active system in the future, but for this project my real interest is a 'Classic 3 way' (yes, the ubiquitous 'monkey coffins' of the 60's, 70's, and 80's) so will undoubtedly stay passive at this time (besides, I really can't afford the extra amps at this time). Yes, that means I will be stuck with the limitations of the form - but I also mean to learn a lot about those limitations.

Speaking of which - what do you know (or anyone else?) of the mechanism of the high SPL distortions that an active crossover resolves? Do these distortions originate in the passive crossover then? What in the crossover causes them?