Sealed Box Windmill Tilt

Redhanded · « **on:** 1 Nov 2006, 03:09 pm »

Yes, I know--which means you don't have to remind me--that normally, this plea is 99% likely to fall on deaf ears, and even here, it may be 80% likely to be ignored. But I have to try. You see, I have a pressing hi-fi problem...a high-end handicap: I don't like loudspeakers with holes in them.

My ear/brain is sensitive to bass for some reason. I can hear standing waves, and I'm almost allergic to room overloading. Bass reflex speakers have always sounded wrong to me...or, more accurately, they sound anywhere from "almost just fine" to intolerably flabby and undifferentiated. What they often sound like to me is, "one note with an extra note." I live with 'em. I have to. But I don't love 'em.

Time was, the commercial speaker market was littered with actual acoustic-suspension designs. Time no more! Almost nobody makes them now. The last manufacturer I was aware of that was devoted to sealed box designs was Hales, but my guess is that Mr. Hales had ruined his upper-frequency hearing listening to rock and roll, because Hales speakers (the lesser ones I heard, anyway) were characterized by deliciously perfect bass and zingy, overbright, tipped-up treble. They're out of business now anyway. Another sealed design I know about is the old ACI Opal (at one time available as a kit!), and I'm on the lookout to hear a pair of those if the opportunity ever presents.

Meanwhile, I go on questing....

I originally "discovered" GR Research because the A/V-3S is one of the very few sealed-box speakers on the market. Of course for 2-channel music-listening it's not close enough to full range, which gives rise to a host of other problems that I should be able to cope with, but so far just, er, haven't.

So anyway, with the advent (sigh...) of the M-165X woofer, presumably Mr. R. is working on some new designs. Enter my hopefully timely plea: is there any possibility...please...pretty please...that just ONE, eventually, could be a more-or-less full-range actual true sealed-box design?

My perfect speaker would be a simple thing: anechoic -3dB point of 42 Hz or lower, sealed rectangular box, narrow baffle i.e., good imaging) and a conventional silk tweeter (or anyway not a metal one, or not a metal-sounding one); 8 ohms nominal impedance, 5 or 6 minimum, and 90 or better dB/w/m efficiency. (All of these parameters I've settled on over years of listening to hundreds and hundreds of speaker types.) One or two woofers, doesn't matter. Floorstander or stand-mounted, doesn't matter. Just no #$@! holes....

Simple, but elusive. Believe me, I know I am in the minority. I know this is probably another tilt at a windmill. But I have to try. "Don't ask and ye shall not receive." You understand.

Danny Richie · « **Reply #1 on:** 1 Nov 2006, 05:48 pm »

Okay, I'll help you out.

How about this: http://www.gr-research.com/kits/ob-7.shtm

The mid-bass woofers are in an open baffle. It doesn't get any better than that and it minimizes room interaction.

Then there are 4 M-130 woofers in a series parallel configuration (back to 8 ohms). These are all in a sealed box and are -3db down at around 80Hz. With room gain it might get down to 70Hz.

Then there is a 12" side loaded woofer in a separate sealed box with a plate amp on it that makes it completely adjustable. You can turn it barely on or even off if you like. It will hit a -3db in the mid 20's with the crossover point set to the 40Hz point.

It's an easy load to drive and it has 91db sensitivity.

What else would you like?

There are some more pics here: http://www.audioxsell.com/community/events/2/163/Rocky-Mountain-Audio-Fest-2006/GR-Research.htm

Hank · « **Reply #2 on:** 1 Nov 2006, 06:52 pm »

Quote

So anyway, with the advent (sigh...)

Wanna buy my original pair of the Large Advent speakers? aa

Seriously consider Danny's OB-7's. If that's not in your budget, maybe a M-165X two-way sealed could be designed. Are you intent on using a "conventional" dome tweeter?

Redhanded · « **Reply #3 on:** 1 Nov 2006, 07:36 pm »

>>>Okay, I'll help you out.

>>>How about this: http://www.gr-research.com/kits/ob-7.shtm

Thanks for the reply, but now is where I feel like a guy who's obsessing over a 4-cylinder car with a carburator and somebody says, "Here, try this...airplane!"

Even the phrases with which I'd try to apologize sound either confrontive or condescending...you know, like "I'm sure the OB-7's are very nice but...," or "Thanks, but that's not really what I had in mind...," or "Not that there's anything WRONG with those!"

I'm sure I'm being at least stubborn, if not also asinine. Honest, I'm not criticizing your product line. You make a lot of really cool stuff. I know I'm out of step. But what I want is something...PLAIN, if you get my meaning. Simple. Just a two-way speaker in a rectangular sealed box. That goes just deep enough.

I know I'm asking for water when I'm being offered wine. But I've got the bug--you know what I mean? When you get the bug? The bug to find what it is you have in mind. Because here's the thing...I know from experience that even if I were to buy'n'build the OB-7's, it wouldn't help. I'd still be looking for that elsuive, plain-old 2-way sealed box loudspeaker ANYWAY!

Wandering the plains with my lance and mule....

Blaine_M · « **Reply #4 on:** 1 Nov 2006, 07:58 pm »

I believe Danny has stated before that the AV/3s can be built deeper to get a lower playing speaker. I dont' recall the details on that though...how low it would go, and how much deeper etc....

Redhanded · « **Reply #5 on:** 1 Nov 2006, 08:09 pm »

Quote

maybe a M-165X two-way sealed could be designed. Are you intent on using a "conventional" dome tweeter?

Yeah.

See, I don't know anything about speaker design or engineering. I'm just going purely empirically. I started listening to speakers 30 years ago, and I noticed that I didn't like everything I heard. In fact, I liked very few things I heard. So I started listening to lots more speakers. (Even worked in the business, for a time.) And a few speakers stuck out as being ones I liked. I was curious about this. What separates the ones I like from the ones I don't, I wondered? So I started to try to pay attention to what it was I responded to. Everything I've listed above is just the result of a long process of winnowing...of narrowing down specific things I have heard into a set of generalities. I learned I like small two-way speakers (Rogers LS3/5a, Celestion SL700), speakers with no hole in the box (that's all I knew at first) or that used a passive radiator (the old Ohm H, the B&W DM7, the Thiel 1.6), etc. I almost always like woofers (I suppose what I really mean is mid-woofers) made of paper, for instance. Why? No idea, really. I just tend to like 'em.

25 years ago I was walking around saying "I like speakers with narrow fronts." And people would look at me like I was crazy. Now we know why narrow baffles sometimes image better but back then all I knew was that for some reason the speakers I tended to like mostly tended to be deeper than they were wide. I had no idea why. It was entirely empirical. I just got it from listening carefully and paying attention.

So every time I'd notice that I liked a speaker's top end, for instance, I'd try to find out how that speaker handled the highs. And nine times out of ten, what I'd find out was that the speaker used a "silk dome tweeter." Now, I don't really know what a "silk dome tweeter" is, or whether what I've responded to has to do with the tweeter being a silk dome, or whether anything else is better or in what way. All I know is what I've learned about myself and my preferences from experience.

And don't get me wrong here, it's not that I can't enjoy other speakers or even that I "need" to have the speakers I'm describing. The speakers I own now are bass-reflex floorstanders with plastic woofers. They sound okay. They're paid for. I'll live.

The reason for my "quest" is just that I'm just curious as to whether a speaker that combines all of the tendencies I've isolated over the years would be one I'd particularly like, or that would have a particular identifiable quality that others could appreciate.

So my problem here is that if I built a speaker that met all of my other general descriptive parameters but had, say, a ribbon or a metal tweeter, then the fix I'd be in is that I'd still be left wondering what the speaker would have sounded like if it had had a silk tweeter.

See what I mean?

Danny Richie · « **Reply #6 on:** 1 Nov 2006, 08:35 pm »

Hank had a good suggestion for you then. I have a new design that I am working on for RAW Acoustics that uses our new M-165X and the RAW Acoustics ribbon tweeter. Hank is building the first set. You can easily plug the port with foam or build it sealed if you want. That will be an outstanding two way and it will have pretty good extension in a sealed box.

You could also consider the new O-3: http://www.audiocircle.com/index.php?topic=32079.0 and you could build a sealed version of it. It has a very adjustable lower end that can easily allow integration into any room.

A real standout design that is very inexpensive is the new A/V-O: http://www.gr-research.com/kits/avo.shtm It's another omni-directional design. It too can be built into a sealed box, but it won't have a lot of low end extension that way.

Redhanded · « **Reply #7 on:** 2 Nov 2006, 01:22 pm »

Thanks. I will keep an eye out for the O-3 kit, and I may indeed build that. I have heard several upward-firing speakers over the years (one by a company I believe was called Samadhi or something like that) and of course Allison. I've always liked them. Siegfried Linkwitz markets a kit for an upward-firing speaker with an amplifier in the base. The thing looks like a submarine periscope! IT should be named the "Batchelors Only."

As far as my experiment is concerned I think I will try a different tack. I think I will see if I can find or hire someone to design a crossover for me for the Dayton DC200-8 8" Classic woofer and Dayton DC28F-8 1-1/8" silk dome tweeter, in a Parts Express box. I think explaining the genesis and evolution of this obsession of mine in my last post convinced me that it is really only an EXPERIMENT, to satisfy a long-standing personal curiosity.

If anybody knows someone who might want to design and build my spec box speaker, let me know, would you please? And thanks to everyone for all the help and educating.

Danny Richie · « **Reply #8 on:** 2 Nov 2006, 02:20 pm »

A couple of pieces of advice for you.

The key to whether a speakers sounds good or not always comes down to the crossover and crossover design. Go for something known, proven, tested, and measured, so that you know what your getting.

Secondly, if you are going to spend a couple of hundred dollars on drivers, parts, and design time, you might as well start with something that in the end will sound good and not sound like a bunch of cheap drivers in a box.

Consider something like our A/V-O. The whole kit is only $249. You can build it sealed and then if you want to extend the bottom end then you can cut a 2" hole in the back with a hole cut saw and slide in the port.

It will give you good bass extension without the issues that you had with other ported boxes.

Hank · « **Reply #9 on:** 2 Nov 2006, 05:42 pm »

Redhanded, what Danny said. If you find someone who is GOOD at crossover design, not just someone who has design software, it will cost you quite a bit. Then, what if the result was another empty windmill?
Go with a proven design that's inexpensive, like the A/V-O, then if it's not quite the grail, you can continue your quest without having lost a bundle.
I do admire your persistant drive towards your goal and wish you success.

David Ellis · « **Reply #10 on:** 2 Nov 2006, 06:07 pm »

Dear Redhanded,

I hear your pain, but getting past accounting & marketing departments is very difficult for any/all loudspeaker manufacturers. With regard to marketing : The general public believes that F3 is the most viable predictor of bass response. The general public also enjoys listening to a slightly fuller/uncontrolled bass. With regard to accounting, it is less expensive to build the same bass system in a ported enclosure with the same F3. Further, above the tuning frequency a ported cabinet requires LESS X-Max rigor on the woofer. Ported cabinets having the same F3 are smaller than their sealed counterparts. So, while you may want a sealed cabinet, you must be willing to pay the price. Most American's are not willing to pay the price and therefore 99% of the hifi speaker market uses ported woofers.

I can't think of any good sealed cabinet hifi speakers commercially made today. As you mention, the Hales speakers were very good. I found the Revelation 2 very surprising. Also, the NHT 3.3 (I think?) was a decent speaker. But... as you convey, these speakers guys went out of business.

I did manage to build a very good 3-way speaker a few years ago using drivers from Danny & Jeff drivers. To this day, it still has the very best bass I have heard from any loudspeaker - including those from Hales and... many more profoundly expensive ported speakers. Oh, and it uses the SCC300 woofer in @ 4 cubic feet sealed. Sealed isn't always better, but I do agree with Vance Dickason in this regard. Given the same quality driver and the same quality of implementation a sealed bass system is better - yup.

Dave

slurve · « **Reply #11 on:** 2 Nov 2006, 06:15 pm »

Redhanded

You may want to look into the Merlin Music TSM speaker, I beleive it fits your criteria.

J.

EProvenzano · « **Reply #12 on:** 2 Nov 2006, 06:30 pm »

Hello folks!

I've always read about people stuffing or sealing their ports because they favour the interaction of a sealed system in their room.

My question is, should a cross-over be optimized in order to do this properly? What are the ill effect, if any, of stuffing your ported speaker?

I recognize that the roll-off usually occurs sooner and shallower, relatively speaking. I've also read that the box volume might need to be optimized.

Thank you!

Redhanded · « **Reply #13 on:** 3 Nov 2006, 04:40 am »

Quote

You may want to look into the Merlin Music TSM speaker, I beleive it fits your criteria.

Wow, it really does. I had no idea such a thing actually existed. Too bad I'll never knew what it sounds like (I mean, unless I can find a Merlin dealer who had one set up....)

But thanks, I appreciate the tip.

--Mike

Redhanded · « **Reply #14 on:** 3 Nov 2006, 04:46 am »

Quote

With regard to accounting, it is less expensive to build the same bass system in a ported enclosure with the same F3.

Dave,
Thanks for your thoughts. Re the above, granted, but I still question why this should be such an issue in the high end. It seems to me it predicts that British floorstanders and department store speakers would all be vented, but with the high end's "prestige pricing," where higher prices are better, why does it still hold? I mean, I've seen speakers in the "admittedly expensive" category selling for up to $15k extolled as "good value" by the audiophile magazines. Some of the commercial high end speakers must rely on the highest possible worker wages, execrable economies of scale, and the best parts quality imaginable, and still struggle to put value into their products consistent with their pricing...

Redhanded · « **Reply #15 on:** 3 Nov 2006, 12:50 pm »

I just want to announce that I've started a very modest website on this topic called THE SEALED BOX. My intention is simply to list the few remaining contemporary iterations of the classic acoustic suspension loudspeaker. Have a look and see what you think....

http://sealedbox.blogspot.com

Mike J.
The Online Photographer
http://theonlinephotographer.blogspot.com

PaulHilgeman · « **Reply #16 on:** 3 Nov 2006, 01:29 pm »

Quote from: EProvenzano on 2 Nov 2006, 06:30 pm

Hello folks!

I've always read about people stuffing or sealing their ports because they favour the interaction of a sealed system in their room.

My question is, should a cross-over be optimized in order to do this properly? What are the ill effect, if any, of stuffing your ported speaker?

I recognize that the roll-off usually occurs sooner and shallower, relatively speaking. I've also read that the box volume might need to be optimized.

Thank you!

Like anything, you are free to try, and yes, tons of people have good results because the natural bass roll-off of a sealed enclosure more closely matches their room gain curve.

The crossover would not need to be changed in about 99% of the cases. There are some oddball things that a designer could do, but for the most case, no.

Generally a woofer that is engineered for a ported box will not perform well in a sealed box. There are a few special cases, but most woofers that work in ported boxes well will roll-off very high in a sealed box. Most woofers designed to work in a sealed box will either not work in a ported box or work in VERY large ported box and will probably play REALLY low. Because of this, many ported speakers will start to roll-off around 90 or 100 Hz when their ports are stuffed.

My Ronin uses a 10" woofer in a sealed enclosure, about 1.5 ft^3, Qtc is 0.65. The F3 is 36Hz, the F10 is dead set at 20Hz.

Regards,
Paul Hilgeman

ohenry · « **Reply #17 on:** 3 Nov 2006, 01:34 pm »

Quote from: Redhanded on 3 Nov 2006, 12:50 pm

I just want to announce that I've started a very modest website on this topic called THE SEALED BOX. My intention is simply to list the few remaining contemporary iterations of the classic acoustic suspension loudspeaker. Have a look and see what you think....

http://sealedbox.blogspot.com

Mike J.
The Online Photographer
http://theonlinephotographer.blogspot.com

Don't forget NSM Audio...

Redhanded · « **Reply #18 on:** 3 Nov 2006, 01:37 pm »

Paul,
What's "my Ronin"?

GHM · « **Reply #19 on:** 3 Nov 2006, 01:41 pm »

While I tend to agree on the sealed speakers having the better bass. I think where ported is concerned you should pin point the exact ported design. I can tell you a good transmission line ported speaker will give you the same natural roll off that you seek in a sealed box. Albeit with better results depending on the design. Here's and introduction to these designs Design Philosophy of TLs. MJK whose been posting recently on this site can explain this better to you than I can. From listening to one of his designs..this guy really knows his stuff!