4-way speaker designs

[Jed]

Lately, I've been thinking about a 4-way speaker. Tweeter to 3.5k, then dome mid to 900hz, 7" mid woofer to a pair of 10-12" woofers at 250hz. This might be a crazy idea considering how difficult even a good 3-way can be, but I just wanted to know your experiences with such designs or your opinion.

I like the idea of having the entire system all passive, for some reason subwoofers don't sound right to me (hard to integrate) for music playback- hence the 4-way idea.

When I get bored and obsess about speakers it always comes down to creating a beast of a speaker.

[joecarrow]

If you replace the word "subwoofer" with "bass bin", your searches may yield some projects that are out there. Also, in Kingpin's thread, he's added two 12" woofers to the Dayton RS 3-way. That's a 4 way monolith for you!

Are you sure you want a passive crossover at 250 hz? That sounds massive, not to mention expensive. If subwoofers don't sound right to you, perhaps you are having problems with room interaction. A little treatment, careful placement, and precision equalization can go a long way to correct that.

[J Walker]

joecarrow:

Could you refernece "Kingpin's Thread" for some reason I just can't find it.

Thanks.

[Jonasz]

Here you go: http://www.htguide.com/forum/showthread.php4?t=20872

[Jed]

I like the modular approach as well (stacked sections)- such as the picture in my first post. That way I could move it piece by piece. :-)

Well, I've heard a few subs crossed over to 2-ways and I have felt that a full range 3-way sounds more seamless (sorry about this generalization). Perhaps there is some objective reason for this. If so I'd be interested to hear about any theories you all might have.

[Marzen]

I spent some considerable time working on a 4 way using the Dayton reference line of drivers (which I had on hand). The biggest obstacle for me to overcome was that using two bandpass filters would push the impedance down very low through these two regions. Especially when using parallel LR4 networks with added notch filters. Lower order filters reduced this effect somewhat.
After being amazed by the bass output of some transmission line 2 ways at a DIY show, I think I may have a go at modifying a sealed Dayton 3 way into a ported transmission line for a TMWW.
-Ward

[ThomasW]

An MTM or MT sitting on actively crossed over bass bins and used with a sub, are easier, almost as cost efficent and have no passive XO insertion losses. And you can use a couple lower cost amps instead of one more $pendy one.

[JonMarsh]

Lately, I've been thinking about a 4-way speaker. Tweeter to 3.5k, then dome mid to 900hz, 7" mid woofer to a pair of 10-12" woofers at 250hz. This might be a crazy idea considering how difficult even a good 3-way can be, but I just wanted to know your experiences with such designs or your opinion.

I like the idea of having the entire system all passive, for some reason subwoofers don't sound right to me (hard to integrate) for music playback- hence the 4-way idea.

When I get bored and obsess about speakers it always comes down to creating a beast of a speaker.

The Sentinal may be in most regards matched or outperformed by the Isis, in spite of it's built in sub amps and other gizmoids. Jut my opinion, of course. The four way approach makes sense for the Sentinal becuase the versions of Eton woofers available at that time didn't have copper in the gap or underhung VC designs, and though the cone is well behaved up higher, the motor isn't. They would not go high enough to match with the C79's, hence the 9" filler driver- derived from an 8-800 Eton. Which is not the last word in distortion in the upper midrange, either. BUT going 4 way certainly cuts down on the driver intermod.

Your idea is doable, but you may want to use at least one active crossover section - bandpass filters have some curious behavior and self peaking, and the closer the crossover points, the more problems. 800-3.2 kHz is what I've found works nicely for a good dome mid, then to tweeter. 250 Hz sounds about right to me, and is doable passive, but a little expensive. The trick is deciding on what network topology to use to manage the BSC comp.

I think the Wilson X1 and X2 an Max should have been four way designs configured the way you're talking about- the Evidence four way Dynaudio systems sound very good.

[Jed]

The Sentinal may be in most regards matched or outperformed by the Isis, in spite of it's built in sub amps and other gizmoids. Jut my opinion, of course. The four way approach makes sense for the Sentinal becuase the versions of Eton woofers available at that time didn't have copper in the gap or underhung VC designs, and though the cone is well behaved up higher, the motor isn't. They would not go high enough to match with the C79's, hence the 9" filler driver- derived from an 8-800 Eton. Which is not the last word in distortion in the upper midrange, either. BUT going 4 way certainly cuts down on the driver intermod.

Your idea is doable, but you may want to use at least one active crossover section - bandpass filters have some curious behavior and self peaking, and the closer the crossover points, the more problems. 800-3.2 kHz is what I've found works nicely for a good dome mid, then to tweeter. 250 Hz sounds about right to me, and is doable passive, but a little expensive. The trick is deciding on what network topology to use to manage the BSC comp.

I think the Wilson X1 and X2 an Max should have been four way designs configured the way you're talking about- the Evidence four way Dynaudio systems sound very good.

I've got a few drivers left over from a previous project I might break down for this 3-way + Active bass bin/ 4-way idea.

Eton ER4- which in many cases and configurations is only good down to 3.5kish in a non-reflective backed enclosure.

I also have a Eton 7-375 with the more modern motor I can use.

Obviously, even though Eton has a kit 2-way with these drivers, I think it might be interesting to do a dome mid between the 2 drivers. Also, this Eton 7" starts to have rising distortion centered at 1.5k based on the measurements from Klang and Ton I've seen.

The Eton 7-375 doens't have enough bass output because of its 4mm Xmax, so I'd like to take some of the burden of low frequencies off it.

Your tests of the Aurasound 10 or 12" look good.

Just thinking when I should be over at the shop chopping wood for my other projects.

Jed

[ThomasW]

Jed,

Here you go..... :B

http://home.wanadoo.nl/e.van.voorst/ProjectSpeakers.htm

[Jed]

Jed,

Here you go..... :B

http://home.wanadoo.nl/e.van.voorst/ProjectSpeakers.htm

NiiiCE! ;x(

[JonMarsh]

For some reason now that link isn't working. I archived it a few months back in case it has permenantly disappeared (I'm assuming it was the linke to the Sentinal Klone project).

[ThomasW]

http://web.archive.org/web/*/http://home.wanadoo.nl/e.van.voorst/ProjectSpeakers.htm

[Xmax BR]

Or

http://www.htforum.nl/yabbse/index.php?board=24;action=display;threadid=8497

[]´s

Renato

[TacoD]

The Dutch design is a scaled down sentinel with all Thiel&Partner drivers. The xo is done by a pro, namely Charles van Oosterum of OLS (www.kharma.com). He paid big bucks, obviously he will not say how much

[Jed]

Probably won't share the crossover schematic either- its like one of those "Got Milk" commercials.

[TurboFC3S]

Or

http://www.htforum.nl/yabbse/index.p...;threadid=8497

Ha, have fun reading through 127 pages of Dutch!

[ThomasW]

The link in post #10 is working again. I think he just runs out of bandwidth.

[Dennis H]

Anybody else find the interior of those speakers frightening?

[JonMarsh]

Anybody else find the interior of those speakers frightening?

Oh yeah.... like something out of Alien or something.... ;^)

What's frightening is the amount of work he put into a BOX speaker... :W :

And that he did pop for the diamond tweeters....

I'm sure the diaphragm behavior is great, I wonder though if the motor holds up it's end of the bargain- though if similar to the new underhung models, I'd guess it does- at least the new one. Awful pricey, though.

[JonMarsh]

The link in post #10 is working again. I think he just runs out of bandwidth.

Well I'll fix that- I'll download it 10 times!!!! Maybe he needs Virtual Avenue, too. Though I'm starting to get close to my 15GB/month limit fairly often these days- may have to up it again.

[Paul H]

Lately, I've been thinking about a 4-way speaker. Tweeter to 3.5k, then dome mid to 900hz, 7" mid woofer to a pair of 10-12" woofers at 250hz. This might be a crazy idea considering how difficult even a good 3-way can be, but I just wanted to know your experiences with such designs or your opinion.

I like the idea of having the entire system all passive, for some reason subwoofers don't sound right to me (hard to integrate) for music playback- hence the 4-way idea.

After building the speakers shown in my avatar, here's my summary from that thread:

If I was going to do this project all over again I'd create something a little less complicated, but it was a phenomenal learning experience and the resulting full-range dipole is (to my admittedly biased ears) fantastic.

[Xmax BR]

Other....

http://www.dddac.de/op085.htm

Tks,

Renato

[ThomasW]

Other....

http://www.dddac.de/op085.htm

Tks,

Renato

These aren't in the same league. On the surface they look similar, but he uses standard 'box' construction.

[JonMarsh]

Yeah, I kind of "hate" it when people cheese out and use standard baffle construction and segmented bits to emulate the Avalon look without the FB density and contruction. Though I do understand the reasons for simplifying the front panel construction and cutting the weight...

But not something to take too seriously in the big scheme of things...

[Jed]

Yeah, I kind of "hate" it when people cheese out and use standard baffle construction and segmented bits to emulate the Avalon look without the FB density and contruction. Though I do understand the reasons for simplifying the front panel construction and cutting the weight...

But not something to take too seriously in the big scheme of things...

So, could we make a list of how things should be done? 4" thick multi density baffle or cast concrete? Matrix enclosure? Phenolic resin walls?

[JonMarsh]

It all depends on what your goals are, you know? A Modula MT sounds pretty nice in the standard PE box with 1" MDF front panel. But as you want to improve things and reduce the signature of the rest of the system, it gets harder and harder- many paths, many different costs and trade offs... comes down to what you want, what you're willing to live with, etc.

Matrix enclosures are a very good idea... the M8ta and the upcoming M12ta combine the 4" thick front panel and a quasi matrix enclosure using BB ply and HDF. This is an "established" approach with good characteristics, IMO, having built several. (go tap on the front of an Avalon Eidolon compared to most other store speakers, and decide which you think is a more inert wavelaunch platform- check out Rockport, too, if there's a dealer in your area- an equal stretch, I imagine).

The Isiris "production" version will probably include a phenolic/HDF hybrid baffle. For licensing reasons, it's tough to buy raw Corian. Is it worthwhile compared to simpler approaches? Well, we'll see. Maybe it's an uneccessary level of complicatio; I'll have more of an opinion after testing the next prototype baffle with the new drivers (they're shipping today).

~Jon

[kingpin]

Yeah, I kind of "hate" it when people cheese out and use standard baffle construction and segmented bits to emulate the Avalon look without the FB density and contruction. Though I do understand the reasons for simplifying the front panel construction and cutting the weight...

But not something to take too seriously in the big scheme of things...

So what do you mean by cheese out. Being a novice builder what he built looks pretty heavy and dense. I am not being sarcastic Jon.
I was happy with the construction of "Project Overkill" until I read the lower part of this thread.

I understand you guys like to laminate materials like hdf, mdf and bb. Is this what you mean by not cheesing out.

Leaving no cost out but keeping things in a realistic realm what is the right way whether it is overkill or not to construct such a large cabinet.

I can always laminate more layers onto my towers. 8O
Well maybe not. I don't think that's going to happen. :B
Dry weight is already at 340lbs without drivers and crossovers which add another 60-80lbs.

Mike

[ThomasW]

So what do you mean by cheese out.

This has nothing to do with your speakers.

Jon's referring to someone pretending to make a copy of a certain design but actually doing something else.

[kingpin]

This has nothing to do with your speakers.

Jon's referring to someone pretending to make a copy of a certain design but actually doing something else.

I understand Jon was referring to someone else's speakers. :T
I was just curious what is considered the best way of building something so large. Is there a certain formula of materials and optimum thicknesses that one should look for.

I know it's not always about me. :B My ego isn't as big as my speakers Thomas. :lol: :lol:

Mike

[Jed]

Kingpin,

Do you really want your speakers to have 4" thick baffle and 1" thick walls with a matrix enclosure? I'd say your speaker is braced well enough!

Jed

[cjd]

He wants it to promptly force a hole through his floor (due to the weight) so he can install an IB sub.

C