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In Reply to: RE: Amps for Maggies. Tube vs SS (I've searched) posted by paul3 on October 21, 2016 at 09:32:09
I concur with Dr. Chaos that the Spatials and Emerald Physics didn't match Maggies for naturalness. However, we heard them at the same show and I hesitate to judge speakers based on show sound.
What I did notice is that the point source open-baffle speakers give you a lot of the spatial goodness that a line source OB speaker does. Not all of it, but a lot more than you'll get from boxes, in a more compact package.
I'd also try to listen to the Linkwitz which I haven't heard but which gets very positive reviews. Of course it's a kit so you might not want to go that way.
Finally, re your original question, I'd consider going with the .7's and the DWM woofer, which is surprisingly small. It won't have the slam of a sealed sub -- even a larger planar that's flat to 20 Hz doesn't pressurize the room unnaturally the way monopole subs do (instruments like bass drums are dipoles and so never pressurize the room), which means that there's less of the jackhammer-in-the-chest feeling with rock recordings -- but what the DWM will do is reproduce the midbass with planar naturalness. It's a woofer rather than a sub and it won't play super loud but it sounds like you don't really care about the bottom octave anyway. I think if I were in your situation that's the way I'd go -- .7's, which I haven't heard but which got rave reviews, and DWM('s).
Another possibility would be the GR OB subs which use two 12" servo woofers and a plate amp and have garnered raves here. Unfortunately, that's another project that requires some carpentry -- for some reason, nobody makes a commercial open baffle sub. And they could be overkill since you aren't really interested in the bottom octave.
Follow Ups:
> > Of course it's a kit so you might not want to go that way.
Here is a turn-key LX521 system: http://www.magiclx521.com/lxminilxstudio-lx521.html
Unfortunately, a pair of LX521's requires 6 channels of amplification! If you have speakers you are happy with, you can get the same woofer design in the add-on GR Research OB/Dipole Subwoofer. Like the 521, it contains a pair of 12" woofers installed in a W- or H-frame, but unlike it features the Rythmik Direct Servo-Feedback system.
That's actually fortunate, not unfortunate, since multi-amp systems with line-level crossovers are inherently superior.Also, currently, the LX521 system requires 10 channels not 6. :)
Also, the LX521 system does not use 12" woofers.
Also, the complication of a servo-feedback and dedicated amplifier system is not required in this application.
Cheers,
Dave.
Edits: 10/25/16
Right you are, the woofers have a mounting flange of about 269mm, don't know where I got 12". The SEAS driver looks great, with a massive motor. So the Rythmik sub is complicated, but 10 channels (I just looked, and it's actually 8!) of amplification (with controls to adjust their relative levels, etc.) isn't?! Adding an active x/o to mate the OB/Dipole Sub to a pair speakers is pretty straightforward (the First Watt or Marchand will work splendidly), at least for people here, and the sub is self-contained, comprised of two woofers and the Ryrhmik plate amp featuring the Servo-Feedback circuit (along with shelving circuit to compensate for the dipole 6dB/octave rolloff). The 521 is a very well-designed loudspeaker, of course, but if one has a speaker that is well-loved (and perhaps "better" than the M/T section of the 521), the GR/Rythmik sub is an attractive option for adding high-performance bass to it for a modest amount of $ (about two grand built).
As I mentioned before, that GR/Rythmik stuff is mostly marketing.
Remember, there's nothing magic about sub-woofers....even dipole ones. They're fairly straightforward to design/build....even servo ones.
I suggest to not get too far sucked into the audiophiledom that Danny and Brian exist in.
Cheers,
Dave.
Davey has his opinion about subs, both "standard" and servo feedback, Paul McGowan of PS Audio and Genesis has his: "There are many great subwoofers available today. Perhaps my favorite is REL out of England. But even as good as REL subs are, they don't quite live up to the Nth degree afforded by a properly designed servo version. That's always been a mystery to me, why servo subs aren't more prevalent."Speaker designer Jim Salk offers many different models, both small and large. He has a few top models into which he incorporates the Rythmik Servo-Feedback Subwoofer. That's right, a very competent speaker designer installs the subwoofer system of a "competitor" into his own product, in place of the passive sub he surely could have designed himself. Jim also offers the subs installed in an enclosure of his own design and build. Mostly marketing hype, I suppose Davey will again suggest.
The famous mastering house in New York, Sterling Sound, who does a lot of work for the LP reissue labels and other perfectionist orientated customers, had their choice of any sub on the market for their monitoring systems. They chose the Rythmik F15, installing a total of eight of them in their rooms, apparently for marketing reasons ;-).
For something as "straightforward to design/build" as a sub, it's curious how so many perfectionist music listeners have for so long found them to not meet their standards in music reproduction. I guess they all got "too far sucked into the audiophiledom that Danny and Brian exist in". If you are one of those, and don't care to observe Davey's admonishment, if not wisdom, you are free to check out the uncommonly good Rythmik and GR Research subs. I did, and now, unlike Davey I am going to guess ;-), own both. Perhaps he has designed and built his own. As "there's no magic to sub-woofers", why not, right?
Edits: 10/27/16 10/27/16 10/27/16 10/27/16 10/27/16
The point is not that some of the commercially available sub-woofers work well. The point is the average audiophile has available to him excellent drivers/amplifiers/kits and can easily construct something equivalent (or better) for much less money.Two things to always remember when you read my posts on this forum. I'm all about value and I'm not selling anything. I would have thought that would be very clear by now. :)
Cheers,
Dave.
Edits: 10/27/16
"something equivalent (or better) for much less money". I'm sure readers here would love to learn from Davey of a sub he considers 1- equivalent to a Rythmik model for much less money, and even more so 2- a sub better than a Rythmik model for much less money. I'm sure those readers would also like to know how Davey knows that to be the case, as he has apparently never heard a Rythmik. I have a feeling he finds that unnecessary, subs being as "straightforward" as they are.Davey IS right about the Rythmik F15 DIY Kit being a higher value than the factory-finished F15. By the way, one doesn't have to go to Danny at GR Research to get it---Brian at Rythmik also offers the Kit. I bought a pair of the F15HP Kits myself, designed a 4cu.ft. enclosure (the factory one is 3cu.ft.) with very substantial bracing (8 running side-to-side, 6 top-to-bottom, and 4 front-to-back, one every 5". Overkill, to be sure!), and had a local cabinet maker cut me flatpacks out of MDF, which I assembled and painted myself. Cheaper, and slightly higher efficiency/sensitivity and output thanks to the extra cu.ft.!
The point of my mentioning Jim Salk selling some of his speakers with the Rythmik sub in them, was of how remarkable it is for a speaker company to use a competitors product in their own. I can think of no other example of that having been done (other than raw drivers---SEAS for example, and ICE power modules. But those aren't really competitors to a speaker company like Salk Sound.). Davey dismisses the significance of that, I don't! Regarding Paul McGowan's credibility vs. Davey's, I'll leave that judgment to the readers ;-).
Edits: 10/27/16 10/27/16 10/27/16 10/27/16 10/27/16 10/27/16
Maybe if you edit your post one more time you'll get it exactly the way you want it?
I suggest to take a breath and re-read my posts again, objectively.
I like that you went with the Rythmik kit and built the boxes yourself to save money and build value into your project.
BTW, if you're interested in a nice upgrade to the ET LFT-8 crossover, I have a prototype working fairly well. This is much more involved than the shunt capacitor fix for the woofer resonance I suggested a while back. The more I listen to these speakers, the more I like them actually. I've decided not to sell them. :)
They do need augmentation on the bottom end though if some lower bass at higher SPL's is needed. I have a nice inexpensive sub-woofer upgrade for that too using some larger, but matching, Peerless woofers.
Regarding Paul McGowan: One need only read some of his "Paul's Posts" on their website or his comments regarding technical reviews of the products to understand he has little technical background. He's a marketing/sales guy primarily and most of the technical design of PSAudio products is done by others. If you asked him how to alter the Qts of a sub-woofer system, he wouldn't know where to start.
Cheers,
Dave.
Ya learn somethin' new every day. I didn't know a certain level of technical knowledge was a prerequisite for being qualified to judge the sound quality of music reproduction. Paul McGowan and Jim Salk, get thee to a school offering EE courses before you make any more specious judgments. You audiophools too!The pair of GR Research OB/Dipole Subs I built (the sub is available ONLY as a kit. A couple of Danny's customers are making H-frames as flat packs for reasonable $, and they're simple to assemble---almost as easy as Ikea furniture) are a great replacement for the ET LFT-8b's woofers (the speaker can be used with the woofer's lead disconnected). I didn't get them for that purpose, but got the ET's knowing that would be worth a try. I'm going to compare them to the Tympani T-IV bass panels for an interesting shootout.
Edits: 10/28/16 10/28/16
Ironically, an EE is a mandatory prerequisite to even attempt to discuss the magical properties of the Rythmik products. So says Bring Ding himself.
At this point, I'm pretty familiar with the operation of the LFT-8 speakers. Alternative woofers need to extend up higher in frequency range to mate properly with the bottom end of the midrange transducer. This can get up into the cabinet resonant/issue range of H-frame dipole schemes fairly easily. Actually, I rather like the "hybrid" approach of mating an 8" sealed-box woofer to the rest of the LFT-7/8's, but the problem is the crossover is not that well implemented.
Dave.
Are they really less money, though? Just curious -- the 10" SEAS drivers in the LX-521 V-frame woofer go for $239, while the GR Rhythmik servo drivers are IIRC $189. Though I'm bothered by the paper cones in the latter. Maybe that's just my engineering compulsiveness, but I like something that's pistonic in the passband -- you can always notch out the HF resonance as you did in your LFT-8's.
I'd be curious to hear from someone who's heard both and can compare.
If it makes somebody happy, I will stipulate that the Rythmik sub-woofer setups are not the worst value in the sub-woofer market. There are many that are worse. :)
But, as an example, the Rythmik F15 as mentioned by BDP is nearly $1000.00. Even if we purchased a servo-amp/driver combination from Danny, the out-of-pocket cost would be half that. A person just needs to do a bit of woodworking and you've equaled that system and saved yourself $500.00. To me, that's a better value.
Regardless, for a sealed-box sub-woofer setup, I would select a good driver that's cheaper and mate with an existing power amplifier a user might have kicking around. Now you have something that performs well for really cheap.
Something like this maybe: http://www.parts-express.com/dayton-audio-rss265hf-4-10-reference-hf-subwoofer-4-ohm--295-460
Yes, the Seas drivers as used in the LX521 are rather expensive. As you might be aware, I have my issues with those on a few levels. :)
Regarding the previous post from BDP. I don't really put any faith in endorsements from Paul McGowan or Jim Salk. Paul McGowan has proven himself technically inept on numerous occasions and Jim Salk is not really a speaker designer. Dennis Murphy is. But that's neither here nor there, I guess.
There are many different paths to take when it comes to subwoofers.
BTW, I'm still waiting to hear about the Rythmik 90%. :)
Cheers,
Dave.
Definitely cheaper to do it yourself if you have access to a wood shop. I'm sort of in between in that I have a router but the table saw is in terrible shape which limits what I can do.
In any case if I put it in a sub for the bottom octave I think it's going to be IB, I'm nicely set up for that since the wall across the hall from my listening room hides a staircase to the attic -- all I have to do is shove a couple of woofers in it. I'd need a plate amp, since my old Emotiva and Hafler are boxed up to sell. Or maybe if I get an A-51 to tri amp I can use its fifth channel.
Dipole woofers would be another option. An IB setup is going to excite more room modes.
So what issues do you have with the LX-521 woofers? I did a search last night and ended up reading some interesting stuff but nothing on that. And do you know anyone reliable who has compared e.g. the Seas woofer with the Rythmiks or the Dayton? This isn't something I've looked into systematically -- I want to get my IVA's straightened out and my MiniDSP up before I take on anything new . . . and also want to experiment with using my existing sub in the near field . . . unfortunately, I bought it with the MMG's in mind and it only goes to 25 Hz, which isn't of much use now that I have the IVA's,
Boxing the woofers is not a bad option vice IB. They give you the option to move the woofers around. :)
However, I don't like the idea of plate amps....or at least plate amps mounted in the boxes. I've repaired quite a few that were literally shaken to failure by the box vibrations.
Plate amps are also rather crude in the EQ/xover settings that can be applied. I like the idea of using spare amps/channels and performing the necessary electronic manipulation elsewhere.
Dave.
LOL, yeah, not to mention that I've wondered what would happen to my woofers if I move. OTOH, small room, not much room for subs, and I could be crossing over as low as 25 or 30 Hz so for the most part avoiding modes in the passband.
Interesting about failed plate amps. In the IB case, less of a concern since I could mount the amp some distance from the woofers. If I built a baffle with opposing drivers most of the vibrations would cancel anyway. I would be using my MiniDSP for XO and EQ rather than the plate amp.
Thanks, useful information.
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