Linn, among others, have used a woofer technology known as Isobaric for years. What is it and why do companies use it? PS Audio's Chris Brunhaver explains it all to us.
According to the various articles I've read on the Journal of the Audio Engineering Society, isobaric loading was originally designed to reduce second harmonic distortion of low frequency drivers by 50- percent.
I was the manager and box designer at a high end car stereo shop back in the day on Wilshire Blvd in Santa Monica. We used to do tons of isobaric enclosures back then. One we built using 4 Soundstream woofers, and people from stores across busy Wilshire would come over and complain that their windows were rattling.
Excellent topic, I was thinking about this recently. I used an Isobaric system with dual 12" Soundstream SS-12 subwoofers in my competition car stereo back in IASCA days. Thanks for sharing. PS...really enjoying my BHK monos, BHK pre, and DSD!! Cheers guys/gals!!
I had the pleasure of owning a pair of Linn Isobariks and drove them "Aktive" and it was a "glorious amount of electronics"(amps) and they sounded LOVELY. Great video by the way cheers.
Cool discussion guys! I use 2 dual voice coil 10's in an isobarac config at my lower back in my listening chair. Good for home theater, ofc, but I love it turned down for music as well. It allows tuning of the bass phase at my listening position, and sounds good.. As always, and still, all the best. I have CVA a case in progress, so my most listened to song lately is; "Boy and the Ghost" by Tarja. You'd also enjoy their album; "Beauty & the Beat Live"
Years ago, I made an isobaric 10 inch. Both drivers fired in the same direction. With the size of the box being very small it came out as probably one of the best midrange setups I have ever listened to. Would also handle a lot of power.
In the late 70's and into the 80's Pioneer car audio had a device which wrapped around your neck, like a rolled towel and provided that low bass feeling.
It is actually Stillwater Designs the manufacturer of Kicker subwoofers, not Kicker Car Audio... Aahh, now I will enjoy my sole opportunity to ever correct Chris in all of his videos. The guy is a genius, don't let him go Paul! Fun fact too, only the round solobarics really had that true "isobaric in one driver" design, and they really did I think the 12's has an Fs below 17hz even. Once they switched to the L7 (square in 2001) it was simply marketing. The things loved volume, but were by no means bad drivers.
Went to Disneyworld many years ago and they had a house of the future setup. They had a small satellite/sub system set up in one room to show how you could get amazing sound out of a small system. I was suspicious and looked under one of the benches and found some small exciters, like the butt kickers mounted there. The bass definitely "feels" bigger with a little bit of hidden assistance.
This comes from Car Hifi guys, where there wasn't enough place to put 4 38" woofers. Because Push Pull does'n need big box sizes. I had 4 of them, getting 138db SPL on the tests.
I do not completely disparage ButtKickers (a brand of tactile transducers). While these are not needed in rooms with wood floors, I have observed that audio systems in rooms with concrete floors (such as finished basements) benefit from the prudent use of tactile transducers. The goal of an audio system is lifelike reproduction of sound, and tactile bass is a part of real life (as reproduced in TV and movies) and live music (as reproduced in recordings). When used prudently, these "bass shakers" also seem to tighten the bass response for music in rooms with concrete floors. Some people might amplify their tactile transducers to a degree I would not recommend but it is not my place to belittle them for it if they find the effect enjoyable.
I was so surprised that he brought up the vintage kicker soloBarric subs. I actually just had one 15 inch in my vehicle. It was ok but not enough. I ended up replacing it with a Skar Audio 18inch ported (Sds18) and I am happy with that. I think in car audio a ported design is almost always a must. I also prefer ported for home audio.
When I was younger,I always preferred sealed,just because it was that much tighter. But yes,the right subs,the right enclosure,with a well thought out port,gotta love the extra output. I now play around with dampening my ported enclosures a bit,to really dial in that tightness I crave.
Aperiodic produces a smooth extended rolloff like a transmission line, still the most musical and dramatic bass presentation, like an enormous horn but with a 12db instead if 24db rolloff.
My first experience with isobaric was a chamshelled pair of JL audio 12w 5's in 1.25cu ft.,as soon as they hit the streets,in an '80 Tercel hatchback,brutal. I never knew about the effect on distortion 'til listening today but I remember how tight they sounded comparatively. I didn't like however,the halving of output,which I learned about slightly later. Great fun setup but shortly thereafter I traded them in on a set of the first 10w 6's,a set of three for my newly acquired '83 Z-28. .75 cube sealed ea.,that was amazing at the time,and they sound imo to this day,fantastic in anything I put them in. Best thing in the Camaro was,I was able to fashion a perfect box on the top ledge,directly behind the back seat,rather than using the well like most did at the time,negating all real storage,and impossible to seal without losing serious real estate by squaring up something in the well. The good ol' days of car audio.
My uncle runs a pair of JL 12W-4 (refoamed) subs in a iso ported box tuned at 30hz on a 1000w Alpine Amplifier. Seems to work really well and sound very good.
There are examples of high end loudspeaker mfrs utilizing isobaric loading ... LF drive sections, as well as Mid or Mid-bass. Eggleston Works ... and iirc, Goldmund may have.
I was only researching this idea a few days ago how a buttkicker might enhance 2 channel audio bass and if the sensation might trick the brain into a sense of deeper bass extension. Ill keep watching this concept from PS.
So I use shakers (Tactile Transducers) in my home theater but I went with the Clark Synthesis product from parts express. They are a softer hit and can handle higher frequencies than the buttkickers. I have one on each chair with a small 75 watt amp going to each one. While I have a pair of 18s with a lot of power, my system is in a basement so I wasn't getting the shake I wanted. They do also bring an interesting addition to music. While it's different than a speaker, you feel it in your butt rather than your chest, its one of the lower cost parts of my theater but it definitely adds a lot to the experience :) In my case I added them to recliners and I mounted them to a large piece of wood that spans between the bottom of the frame. www.parts-express.com/clark-synthesis-tst239-silver-tactile-transducer-bass-shaker--300-863
Ha! My first subwoofer system, a cheap Jamo bought in -91 have it's sub configured in that way - Never heard the term though. Still in use as PC-speakers but I recently switched out the satellites since they seemed a bit tired.
I saw an isobaric speaker set up when i bought a polytron ps300 long ago. Its already phaseout in my place but there's still in Indonesia i think. You can search it and ohhh! Its a nice active subwoofer actually with two 6 inch speakers facing each other.
La configuracion cono contra cono para subgraves y graves hace que suene mucho mas detallado todo,ademas de bajar mucho mas profundo.Podria decirse que tenemos un grave analitico y con todos los matices.Yo utilizo la configuracion reflex isobarico desde que lei un documento tecnico de un tal Ricardo de Beyma de hace casi 20 años.No podia creer lo que estaba oyendo.La mejora es escandalosa.Pruebalo Paul Please.Gracias.
The best bass I ever heard was two 12” M&K push pull subs with their best satellites in a hifi shop. KEF has a 2nd generation 9” push pull sub that looks like a winner.
Isobaric woofers are basically not needed anymore, since the advent of magnetic FEA modeling of loudspeaker motors and mechanical FEA modeling of suspension components to produce high-BL woofers and eliminate meaningful amounts of asymmetry. Isobaric push-pull arrangements force the assembly to be essentially symmetrical by coupling the two motors and moving systems together while acting in opposite directions relative to the backplate of either driver, but good component design can now assure not only symmetry but linearity with just a single woofer to buy. Also, high-BL woofers can operate in small enclosures without requiring the two motors of an isobaric pair to be working in tandem to push the piston.
Has Chris discussed Theile/Small parameters? I'd love to hear him discuss the different values, where they come from and how they affect enclosure design.
I think Wilson Benesch still utilizes isobaric loading to give their monitor speakers some serious bottom end - I guess throwing in another woofer for good measure is no big deal at that price point.
Paul great content, can you ask Chris or do a video on subwoofer sensitivity and why it has remained relatively stagnant. Is there no incentive to create 90-100+ dB subwoofers? It seems that the R&D in this department has been left far behind when compared to the leaps achieved in amplifier performance by comparison. Thanks.
Im no expert but I've heard that as efficiency goes up, bass response goes down. I'm not exactly sure why that is but I believe its one of those "Iron law" things.
Linn had mostly moved on from their isobaric speaker designs by the time they started making electronics, so I’m not sure that amp sales were the motivation.
I'm considering using the stairway storage room in my house as a sealed subwoofer box to maximize the but- kicking effect. It's well sealed except for the door, that needs to have some rubber sealing to keep it from vibrating, I guess. Anyone with experience in this idea?
@@jim9930 Parts Express is in my mind. But I was thinking about the HTS545HE-4 Kraken 21" High Excursion woofer in the actual wall that is already part of my home theater room. This woofer can move 7 liters in one stroke and I should be able to get down to 20Hz easily with high SPL. It's a pretty solid wall. I'm also thinking about adding the www.subvo.com sensor to it and finetune some feedback loop algorithm to make it a stairway room servo subwoofer.
@@jim9930 Experimenting with servo feedback takes some courage. If you have ever had a 1000s of Watts amplifier going into some mode of oscillation through the servo sensor with the house shaking and the voice coil glowing, you get some respect for this. I had such an experience a couple of years ago. It's better to first start with the protection mechanism (cut signal if it gets unstable).
@@jim9930 You don't want to take a break and be sitting on the toilet to realize the system starts oscillating...and the building shakes...and then the main fuse blows...and it gets dark...
@@jim9930 I'm sure it's tough to make a venue of many 1000s of seats to sound good. I've been to some large concerts with Pink Floyd, Dire Straits, Cold Play, and others where I got quite impressed how good the sound was under the crazy conditions. Obviously "good" isn't really very good, but at least you hear the music loud and clear without feedback and, if you are lucky, some stereo image. One time I was standing right next to the control area of a Pink Floyd The Wall concert, and it was not just about audio but also about all the visual effects of the huge stadium stage area. Just the quantity of wires being involved is quite amazing.
I put a butt kicker on a chair and when playing electronic drums you basically feel like a god. I also cracked my couch with the thing while watching LOTR.
Lirpa Labs is pleased to announce our new Iso-Sikel woofer featuring a superfluid helium-4 cooled voice coil and field coil magnets system for unsurpassed efficiency. Well, for the woofer; the 1.7 degree Kelvin (better than CERN!) superfluid helium-4 supply system is another matter, but we won't go into that now. Operational impedance is 0.0000000 . . . 00000001 ohms. If you thought the Scintillas were tricky to drive; well, we won't go into that either.
Although we do not commonly reveal such information, Lirpa Labs confirms that Mr. Rat is one of our independent (read unpaid) beta testers. As per our standard policy, we will only reimburse him for the first 3 amplifiers (with notarized and dated receipts required).
Lirpa Labs Bioreplicant Division is pleased to announce that Stephen Smith Mk. !V is now on line. Uhh, you guys did get that instability in the Zero Point Energy power supply straightened out. No? Oh well. LET'S PARTY!!!! Where's the absinthe?
Lirpa Labs Bioreplicant Division announces that Stephen Smith Mk. V is on line. We also announce that due to reliability issues the Stephen Smith series is being boxed pending further evaluation. Wait, what? - off line -
@Fat Rat I’m pretty sure a certain SJ speaker system with isobaric woofer/subwoofer set up is going to be a better experience then butt kickers mounted on plastic chair and using headphones. A+ to you for creativity, tho.
@Fat Rat I first experienced a Butt-kicker (2004) on a friends projection screened, THX certified system. The 2 viewing chairs on an isolated platform, with the kicker mounted. We saw the movie Titanic. At levels over 100 db, so I know what it's like to get servo'ed. These days I live where there is no sound ordinance law. But then generally nobody pushes the issue. However. I had the DL15x's out this summer in the front yard pulling 120 for hours.
@Fat Rat I feel inspired to detail what exactly The SJ Speaker system is. I think you might enjoy that. Since the PS Audio speaker is going to hit soon, looks like a good time to bring on what I have determined to be true in audio. Thanks to Ask Paul and equally, Janina Palmer.
Kicker Solobaric ruined my respect for the Kicker brand. Twisting a scientific term for marketing hype. “It’s like having 2 drivers in one” Don’t do that
