Official Rythmik Audio Subwoofer thread - Page 221

I had a little trouble following all this... There are pictures of the various amplifiers on the Rythmik site, and of course Brian can provide more insight.

Using a passive filter you would like very low driving impedance and very high load impedance, which you have. Yes, a simple first-order RC filter provides 6 dB/octave slope, but many passive filters use an LC circuit to get 12 dB/octave with just two components (the inductor allows you to get an extra 6 dB/octave). There are probably websites that describe the filter, or you could buy one. Most balanced passive filters add an extra component so (+) and (-) signal see the same impedance to each other and to ground.

A typical balanced LC HPF would put capacitors in series with each signal line (+ and -) and an inductor across the +/- signal lines after the capacitors. The inductor is a low impedance ("short") at low frequencies, and the capacitors high-impedance ("open") at LF, so the combination of shunt L and series C provides a second-order (12 dB/octave) HPF.

You could use transformers to convert your single-ended passive design to balanced, but the same effort should get you a new balanced design.

HTH - Don

Thanks again Don. I was hoping that Rythmik offered the connection capability that SVS does on their SB13-Plus, but looks like it's no. If I can't have HPF'ed balanced XLR outputs on a Rythmik sub (which is very understandable), I atleast expect to simply be able to connect the sub to a 2-channel stereo system via balanced XLR inputs and outputs. The most important thing I want to be able to do is send the L & R channel balanced outputs of my stereo pre-amp, to L & R balanced XLR inputs on the Rythmik sub, and for the sub to then send the L & R signal to the power amps from balanced XLR jacks on the sub. It's just like the regular A370PEQ, but with XLR's instead of RCA's, isn't it? But on the Rythmik site I don't see any version of the Rythmik amp that accepts a 2-channel signal via XLR's, nor sends the same signal to the power amps also via XLR's. A single channel yes, 2-channel no. Is there a version of the amp that will even just accept a 2-channel signal (L & R for stereo) on XLR jacks? If so, I don't see it on the Rythmik website. Yes, I realize that most people no longer have just stereo pre-amps, and that balanced XLR inputs and outputs aren't common in home use. But Rythmik's claim to fame is providing the highest quality of music reproduction, yet the companys product doesn't allow for the highest quality hook-up. Is it just me?! The SVS SB13-Plus accepts 2-channel signals via both RCA's and XLR's, and provides for the 2-channel signal to be sent, both unfiltered and HPF'ed (at either 12db/octave or 24db/octave), to the power amps, via both RCA's and XLR's on the sub. Plus, the crossover frequencies themselves (a choice of about a dozen) for both the low pass to the sub (also at either 12db/octave or 24 db/octave) and the high pass to the power amps are selectable via a knob making the choices electronically. After that, mere 2-channel balanced XLR inputs and outputs on a Rythmik sub isn't asking much, is it? I don't want to have to choose between having a Rythmik sub and being able to use my pre-amp and power amp's balanced XLR outputs and inputs. I want both! Putting your power amps directly behind your stereo speakers, and running long balanced interconnects with XLR connectors from your pre to your power, and short wire runs from your amps to your speakers, is the ONLY way to fly! If I can't put a Rythmik sub into a stereo system and ask only that it can be done on XLR's, what choice do I really have? Unless I go for two Rythmik subs with the A370XLR2 amps!
Edited by BDP24 - 6/21/12 at 9:45pm

Based on a whole lot of hours reading just about every large room ID sub thread there is, and the 1:1 help of a few respected forum participants I ordered an FV15HP for my listening room. I should have stopped reading there, the inner geek in me did not agree. Yesterday I read a thread, with a very large room Rythmik advised the gentleman to choose the F15HP over the FV15HP, so I wonder whether I made the right choice. I've since contacted Rythmik, awaiting a reply.

My room is a refinished basement, a rectangle of 20 x 34 x 8 room. Speakers and display are at the far end of the room on the 20' wall, shifted roughly to the left - about a third of the space on the right side is a small bar area 7' wide, so my HT space itself is about 13'x22'. The only placement option I have for sub is on the left wall (to the right of a couch), pointed either 90 degrees from my main speakers (and pointed at the bar area) or towed in slightly toward the listening area. I don't have the placement options for two subs. Construction is heavy carpet, drywall and wood paneled ceiling.

Music tastes are rather broad. In order of most air time: alternative/indie, classical, rock/classic rock, world & reggae, jazz

My usage is roughly 50/50, I want an immersive HT experience while also preserving accuracy in music listening. Speakers, soon to be ready, are custom Philharmonic Audio 2's, approx 30Hz with planar midrange & RAAL tweeter. While I would prefer sealed I've learned that with roughly 5500 cubic ft ported is probably the better way to go, yet that new feedback to the individual recommending sealed really has me thinking. Watching movies I don't care much to be punched in the chest but I definitely want to feel it, and although much of my music will not reach extremely low when it does I want accuracy.

Rythmik FV15HP has a very good reputation in both applications and my gut tells me this is still the right choice for my space, but my very slight preference for the tighter characteristics of sealed subs and the new hope that a single 15" sealed sub just may work in this large space has me thinking again.

Please, if you must, have at it, but all arguments in favor of dual subs will be ignored. I'd like to focus on specifics and the experiences of others like me with large rooms and those attempting to meet their needs with either of these choices.

Thanks much in advance.

Edit: I finally found the aforementioned thread.
Edited by Nethawk - 6/21/12 at 8:56am

Don't second guess yourself Nethawk, you made a great choice in the FV15HP. That is a pretty good sized basement so at the very least you should have one ported beast. The HP will fit the bill nicely. I seriously doubt you would have enough room gain to make the frequencies below what the FV can handle noticeable on the F15. You chose wisely now go enjoy these agonizing days waiting for it to arrive.

They have a balanced version you can connect XLRs to.

You bought a ported sub to handle your large HT space, and a Rythmik to deliver tightness /musicality / accuracy. Listen to your gut and enjoy your new sub!

And congratulations!

You could always build a passive XLR summer to drive the subwoofer's amp, e.g. http://www.diyrecordingequipment.com/4203/how-to-build-a-diy-passive-summing-box/

Thanks Nemesis, and Brian. So I did have it figured right, needing two XLR2 amps for stereo? Your question, Brian, made a good point, and got me to thinking. I want to roll off the signal to the electrostatics below 80hz or so, to increase their dynamic range and lower their distortion, and knowing you pick your parts after assessing their sound quality, I thought the HPF'ed output of your sub would be a good way to do it. But now that you mention the opamp/ IC in the signal path, I guess not! I could instead run the sub off one of my pre-amps outputs, and run my speakers off of the balanced XLR output of my pre, putting the network Don detailed above (thanks Don!) on my amp's balanced XLR input jacks. Problem solved! Thanks Brian and Don and Nemesis. Now I just have to decide which Rythmik sub to get!

I think you're asking the wrong question . . . Rather than pondering ported vs sealed, have you considered how many subs are needed for that sized room?

its hard to serve two masters (HT and music).... if you spend more hours listening than viewing go for the sealed one :-) and buy another when funds allow

...you could cheat the room by locating the sub nearfield

Listen, I was told an F15 would be good enough for my size room. I will not nor will I ever include the large opening that goes back to the kitchen/diningroom. If I did I would be up to 6K cu. ft. I bought a FV15 based on advice here and the subwoofer shootout. (despite the fact most told me that I needed 2 subs) The FV15 is more than enough for my listening area which is about 2300 cu. ft. And it's rattling things throughout the house in rooms that have nothing to do with my listening area. You made an excellent choice. My FV15 does an outstanding job on movies, TV, AND music. It's a musical sub that kicks major butt with movies.

Jeff

New guy here,

I’ve been perusing some of the 6600+ responses in this thread to see if anyone had built the DS1200s cabinets and noticed there were a few inexperienced woodworkers that could have benefited from a couple of tools/techniques commonly employed in woodworking.

They will save you time, frustration, and money:

Zero-clearance plate
A circular saw can yield a fairly decent cut if you outfit it with a zero-clearance plate.

Here’s how to make one from a piece of scrap fiberboard:
http://www.finehomebuilding.com/how-to/tips/minimize-circular-saw-tearout-on-cabinet-grade-plywood-cuts.aspx
And please—use a sharp blade!

Cauls
Yes, you do need more than a couple of clamps. Not a truckload—but several good clamps along with a few homemade cauls and you’re in business. One caul can do the work of several clamps.




Here’s a link to a comprehensive tutorial by Mike Henderson on how to make wood cauls from 2x4s. http://www.mikes-woodwork.com/Cauls.htm
Edited by Pan Head - 6/22/12 at 10:11am

Sigh. Yeah, one.

Thanks for all of the encouraging posts, I'm now convinced I made the right decision. My FV15HP shipped today. The world is saved, I am... Hiro Nakamura!!

With the right plugin on the MiniDSP, you could feed 2 x XLR to the miniDSP and have it sum them out to the single sub I think.

Check out the "2 way + sub" plugin.

minidsp.com
Edited by Nemesis.ie - 6/22/12 at 9:57am

^ He has a stereo, tube setup and does not want to add SS, let alone ADC/DAC conversion, into the main speaker path. A simple passive summer should do fine for the sub, using the built-in LPF, and a second-order passive HPF would do for the mains.

Curious: Do you have a miniDSP, if so how do you like it? I keep toying with the idea but have no real need; still, it would be fun to play with!

Nemesis and Don---Thanks for the helpful suggestions. What I'm going to do is get the XLR2 version of the plate amp, feed the pair of RCA inputs on the sub from the RCA outs on my pre-amp, then feed the XLR's on my mono power amps from the XLR outs on my pre, putting the roll-off filter suggested by Don on the amps' input jacks. While it's true I won't be using the XLR's on a single sub, I'm getting the XLR2 for two reasons: 1 - When I get a second sub, and run them stereo L & R, I can then hook them up balanced from my pre; and 2 - I have no use for the high level inpus (binding posts) on the other versions of the Rythmik plate amp. By removing them, Brian was able to put every other feature he has on the control panel. Why is running balanced in a home hi-fi so important to me? Well, both my pre-amp and power amps have fully balanced circuits, and measure and sound better when used that way. Plus, they are quite a ways apart (I believe in long interconnects and short speaker cables, if you have a pre-amp with low enough output impedance and power amps with high enough input impedance and sensitivity), so balanced is the only way to go for me. As for the roll-off on my speakers, the electrostatic panels sound much better when relieved of the low-frequency excursions. That's somewhat true for all speakers, but especially mine. Thanks again guys!
Edited by BDP24 - 6/22/12 at 1:56pm

No explanation needed. I have had numerous 'stats roll through my system though never actually owned them (advantage of being in the biz in my wayward youth) and have Maggies now. I use an active crossover to drive all the PAs. panels have limited dynamic range and I don't want to waste it on LF sounds they won't generate, nor the octave above they say they will but exhibit very high distortion when driven reasonably hard.

Interestingly, the sub I designed and built for myself several decades ago because nothing at the time sounded as good for any reasonable price, was a servo design using the second voice coil in an Infinity IRS woofer. All sorts of folk liked it. I could have been Brian.

It's been a week and here are the updates.

First, I followed Brian's instruction to change from LFE IN to LINE IN. The sound level did improve. Before, it was unsatisfactory even at Max level. After, it was acceptable (to me) at Max level. However, it did not leave me much headroom here.

Second, I ordered the Y splitter. With it, the sound level improved once more. Net net, now I'm quite comfortable with sub level at 3 o'clock position.

About the sound:
- My Mozart Grand speakers produce very accurate sound with large sound stage. However, they sound a little bit cold and shallow sometimes.
- Rythmik F12 provides just what I need. It added the depth and warmth that I've been longing for.

About the size:
- I remember someone on this thread said the sub is quite small. Well, it's all relative. The sub dwarfed my Mozart Grand speaker, let alone the Bose cubes of my HT system. I'm so glad I ordered the F12SE not the F15 because the latter could immediately trigger return order from wife Well, actually, I'm not sure about it. She's been very nice about the F12SE, just asked me what it does and said she couldn't recognize the (sound) difference.


Edited by Foreverandone - 6/23/12 at 6:36pm

Don---Maggies! I loved mine, when I had the original 1-U's in the mid-70's. I too bi-amped mine, but with that little passive x/over ARC offered back then. Those speakers blew a lot of my friends minds (I was the only audiophile in my crowd. Stll am!). By the way.....I bought my Maggies from Walter Davies, the guy who does the Last record care products. In the 70's he had a hi-fi store in Livermore, CA. Very nice guy!

I have 3 of them but currently only use one at a time.

Works beautifully for bass EQ (via REW), if I was to EQ the speakers as well, I'd probably go for the 10 x 10 (8 x 8 analogue) unit as it supports 96KHz, the 48KHz of the standard one is plenty for sub frequencies though.

The 8 x 8 unit is a bit expensive though at about 5x the price of the 2 x 4.

@BDP24: I learned decades ago that servos worked best for me and my Maggies. Rythmik was an easy choice, especially after going back and forth with Brian and learning what an incredible guy he is in so many ways.


@Foreverandone: So, are you done yet? Glad you are getting everything dialed in!

@Nemesis.ie: I may pick one up for fun. I only need the small one, but would add a gain stage to make sure it can drive my amps to full scale (output of the unbalanced models is a little low). Primary use would be the sub, though it is tempting to see how it does on the mains. I have heard mixed reviews on sound quality, ranging from "completely transparent" to "completely changed the sound of my XXXX for the worse". I was kind of waiting to see if they upgraded the 4x4 with higher output and sampling rate. I'm in no rush.

Since learning of Rythmik, I have read almost everything on the website, and am now making my way through all of the postings on this thread (I am up to page 140). Getting into Rythmik subs is like peeling an onion---every answered question leads to new questions! Here are my questions:

1 - I have just read about the XLR2 and XLR3 versions of the Rythmik amp. The pre-production silkscreen layout of XLR2 that I saw had "HPF Output" RCA jacks next to the "Input" RCA jacks, whereas the production XLR2 and 3 have "LFE Input" in their place. What is an LFE signal? Is it for HT use only? Can a buyer of a sub with either XLR2 or 3 request outputs (either unfiltered or HPF) instead of "LFE Input" on those jacks?

2 - Do the XLR versions of the A370 have a different price than the PEQ version?

3 - Are XLR2 and 3 available now?

4 - On a different subject.....The 370W F15 comes with the 1501 driver. What is the added dollar amount for getting a 1505 driver instead? Can the 1510 driver be partnered with the 370W amp? The price differential?

5 - And finally, regarding the discount on multiple subs.....is it only the second sub that is discounted 10%, or both? If I purchase two at the same time, do I get 10% off each? If I get one sub now and the second in, say, six months, do I at that time get 10% off the second sub AND 10% off the first sub, retroactively, with the 20 % for both taken off the second as it's time of purchase?

That's it for now! Thanks---Eric.
Edited by BDP24 - 6/26/12 at 9:10pm

Brian---Does this apply to the XLR amps as well? Can an XLR2 or XLR3 get "HPF OUT" on RCA jacks in place of the "LFE IN"? Sorry if I sound like a broken record!



!!! A new thought! The XLR2 has a three position switch, the XLR3 a two position. Is it possible to offer the XLR3 with three positions, the two already on it ("NORMAL"---"L SOURCE IN" and "R SOURCE IN", and "DUAL"---"SOURCE IN" and "LFE IN"), and the new added third position for "SOURCE IN" on one of the XLR's and "HPF OUT" (or unfiltered) on the other? That way a user running balanced can use a single sub for stereo now, and then add a second when he/she is able to, keeping the original XLR3. Just a thought!
Edited by BDP24 - 6/27/12 at 4:40am

Hi Brian,

You mentioned before that the A370PEQ amp when plugged into 220 volts will be able to produce a bit more that the rated 370 watts any ideas estimate on the wattage ?

The reason I am asking is that I am in a pissing contest with my neighbor who has a "3500" watts mini component system with TWO 6.5 subwoofers, which when added together makes a "13 inch subwoofer".. which is just 2 inches short of my 15 inch sub, I just feel inadequate saying that I just have 370 watts

Brian,

Did you get my PM?

Area = pi * r^2

Two 6.5" drivers = 2 x 33.18 = 66.4 square inches

One 15" = 176.7 square inches

The 15" driver has 2.66 times the area of the two 6.5" drivers.

Jez' sayin'....