Originally Posted by grigorianvlad
BDP24, a friend of mine pointed me to this thread - and your post in particular - knowing that I am researching Rythmik subs . I ordered the Eminents (LFT-8b) 45 days ago. Bruce assures me they will be shipped in a week. I have a few questions for you.
1) Did you consider purchasing a Hsu subwoofer ? I have never heard neither a Hsu nor Rythmik, but these two brands are described as best to be used with Maggies or Eminents. If you did, what made you choose a Rythmik?
2) Which Rythmik sub would you choose as best ? Is it the FV15HP or the F25? Mostly it will be used for music, not HT.
3) How low did you setup your crossover? 40hz, 80hz?
4) How would you describe the ET sound as opposed to the Maggies? I have 2.7's. I currently use them in a parallel stereo set up (meaning there are two power amps powering a pair of Polk LSiM 705s and the Maggies 2.7). So, if the ET's are close to the Maggies I may still use both Maggies and ET's at the same time.
5) How large is your room?
6) How far did you position the ET's from the rear wall? Did you experiment with that distance? What did you observe as you moved the speakers closer to the back wall?
7) Did you also order Anchor stands with the ET's? Did they make any difference?
8) Given the resources, would you consider biamping them?
9) Which speaker cables do you think work well with the ET's?
10) The Eminents have 3 tweeter settings . Do you run yours on the highest tweeter setting? Is there actually an audible difference?
11) When you bought the Eminents, how long did you have to wait before they were delivered. I have been waiting almost 2 months, which is a torture.
I started a PM to answer your questions, but then reconsidered. I think there may be enough information of general population interest to warrant this post. At least, I hope so! Grab a cup of coffee, here we go:
1- I bought a pair of the original Hsu HRSW10 subs from Peter at CES in the early 90's to augment my Quad loudspeakers ("loud" speakers and Quad an oxymoron if there ever was one ;-). They are now in a video system, where high performance is not a priority for me. After being out of the Hi-Fi game for a while, I re-entered it a few years ago and started looking into subs. I found the current Hsu's, SVS (initially finding the SB13 Ultra very appealing), JL Audio, Velodyne, Vandersteen, Seaton, Funk, DIY with the infamous TC Sounds LMS Ultra 18 driver, and all the other contemporary contestants. I sympathize with you youngins, having to buy blind, without being able to hear ID subs before purchase. It's not as bad for us grizzled old veterans, as we can tell a lot about a product simply by what the designer has to say about it. Such was the case for me with Brian Ding and Rythmik, and then Danny Richie (a sometimes collaborator of Brian's) and GR Research. My intuition and instincts have proven to be correct. I was looking for the ultimate sub for music when mated with dipole/panel loudspeakers, the most difficult type loudspeaker for a sub to integrate with. IMO, Rythmik/GR Research is that sub.
2- FV15HP versus F25? How did you narrow the choice to those two models, may I ask? Yes, the first decision in sub choice is between sealed and ported, but only the first. One then looks into all the models of that design available. The choice between sealed and ported can be made based on room size, SPL capability desired, bandwidth (how high and low in frequency), budget, and, most controversially, sound quality. Audiophiles "believe" sealed subs sound "tighter" than ported, ported a little "boomier". There are those who say nonsense, the two can not be distinguished in a blind listening test. Brian has supplied technical information on the lower group delay ("ringing") and superior transient response of sealed, and is himself a "believer". The choice is yours.
Assuming you choose sealed, why the F25? A single, or a pair? Do you really need all the output of the F25? The F12, F15HP, and F25 should sound pretty much identical unless you run out of output. How big is your room? How loud do you listen? The ET's play fairly loudly, but not THAT loud. They may be the limiting factor, not the sub. DonH50 found a pair of F12's to be all he needed for use with his speakers, the excellent Maggie III's. I WOULD stick with the "premier" Rythmiks (the F12, F15HP, and F25), not the economy models. This is for music after all, mankind's most important endeavor! If you have the dough, why NOT go for the 25's, ay?
I had decided on a pair of the DIY F15HP, wanting to put the amazing Rythmik DS1510 driver and H600 amp into a 4cu.ft. enclosure of my own design (dual-walled, the chamber between the walls filled with sand, and old trick from the 50's). But then I read about a very special design Brian and Danny had co-created, the OB/Dipole Sub. You can check it out on the GR Research site. Danny is a loudspeaker designer, being particularly gifted in Open Baffle and cross-over design. Upon hearing of Brian's Direct Servo Feedback system, he envisioned it incorporated into a sub of OB/Dipole design. I already knew of an OB/Dipole sub that the Finnish company Gradient had offered in the 80's and 90's, designed specifically for use with the Quad 63 loudspeaker. The Rythmik/GR Research OB/Dipole sub is the ultimate incarnation of the OB/Dipole design, and is, imo, THE sub for use with all panel loudspeakers, whether ET, Magneplanar, Quad, and all others. But, like all dipoles, it must be positioned away from the wall behind it, it has limited output (compared with a "normal" sub), and most importantly, sounds rather different than sealed and ported subs. "Leaner" is one adjective used to describe it's sound characteristic. It also "loads" a room differently than a normal sub, having a null at each side of the sub frame, just as all dipole speakers do. True, wavelengths at sub frequencies are so long as to be omni-directional, but that does NOT mean that the dipole radiation/side-null characteristic of the OB/Dipole sub is inconsequential. Unfortunately, it is available as a DIY kit only, the two opposing woofers and amp mounted in an OB frame (detailed building diagrams available on the GR website). Certainly not for everyone, in fact for almost no one, only nutty hardcore dipole loudspeaker fanatics. Too bad most people will never hear them (though attendants of the annual RMAF Hi-Fi Show voted it "Best Bass" many years running). At least you can read about them!
Still, I found myself lusting for that DS1510 driver. Being the gluttonous pig that I am, I bought a pair of the DIY F15HP kits as well, and had a local cabinet maker build my enclosures to mount them in.
3- The OB/Dipole sub can be used up to 300Hz, and I use mine in place of the woofer in the ET speaker, from 180Hz down (the frequency of the ET's 1st order, 6dB/octave x/o). Assuming you go with a normal sub, the x/o controls in the Rythmik amps are there to be used, so try all the settings. Start with 80Hz, then 60, 100, and 40. The higher the frequency chosen, the less you will be asking of the ET's 8" woofer, a good idea. It's a fine woofer, and mates well with the ET's magnetic-planar driver, but it is after all only an 8". A Rythmik sub will provide a drastic improvement to the bass of the ET. Plus, with it in use the ET's should be able to play a little louder, especially if you use a filter (even a simple r/c) to roll off their low end.
4- I have heard the current Maggie 1.7i, .7i, and 3.7, as well as the old Tympani T-I (I owned a pair in the 70's), T-ID (owned a pair in the 90's), and T-IV (I own a pair now). There are similarities and differences between them all, but as you will soon have both ET's and Maggies, you can compare them yourself.
5- My current room (soon to change---I'm moving) is 13' wide (I would love a couple more feet), 19' long, with a 10' ceiling. I have 14 ASC Tube Traps (found in the L.A. Recycler for ten bucks apiece!), RoomTune Corner Tunes, and wall-to-wall carpeting. An only okay room.
6- Being a dipole, the ET must be at least 3' from the wall behind them. Mine are now 6' from that wall, 8' from my listening location, and that location 5' from the rear wall. The outside edge of each ET is 18" from it's side wall (it's dipole radiation and line source characteristics allow close side wall placement), with the tweeters on the inner edge, 8' from each other (I favor the equilateral listener/speaker arrangement).
7- I had my ET dealer order the Sound Anchor stands at the same time as the speakers. When so ordered, ET does not send along the stock feet (weird, huh?). It's okay, though---you definitely want the SA's. But you can get them cheaper from The Cable Company than from ET.
8- Bi-amping: With a x/o frequency of 180Hz, why bother?
9- I like Clear Day Double Shotgun cables with the ET's. Of all silver wire construction (NOT silver coated copper), they are reasonably priced at $500/8' pair (I can hear you Flat-Earther's laughing from here ;-), with a 10% discount. Available ID only, though sometimes offered on Audiogon.
10- Ignore the lowest tweeter setting. The middle position provides the flattest middle-high response, with a gently rolled-off top octave. The high setting gives a flatter top octave, but raises the octave below that a little too much. The best compromise will be influenced by the absorption of your room's surfaces, and the sound of the rest of your system, especially of course your power amp. If the amp is a tube model with a slightly soft high end, try the highest tweeter setting first. If it is a slightly bright/hard solid state amp, the middle might be best. The setting is easy to change, so give them both a try.
11- Yeah, ET's Bruce Thigpen must make each pair himself, one at a time! All good things come to those who wait, as my mama use to say.
I hope the above will be of use and interest to you Greg (from your Forum handle I'm guessing that may be your name :-). For the rest of you, sorry!