So, is there a concerning difference regarding the type of amplification used in subwoofers? Specifically, Class D vs A/B? Trying to figure out most "musical" subwoofers (whatever that is), and have noted ML, JL and many others now use Class D, while REL uses A/B.
Do I Really Need a Sub?
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Rel uses A/B on a few subs, most of the T/i models. All the rest are one of several Class D amps.
In the past when I've demoed Class D amps, more than 4 years ago was the last time, I couldn't find any I liked for two channel usage. But for subwoofers I don't know how anyone would be able to tell the difference between A/B and D in those low frequencies.
Gordon Gray
Well-known member
RE: REL. I have one T7i with my Joseph Audio Pulsars. In my "medium" size room, the blend is marvelous with a surprising amount of "deeper" bass depending on the musical material. Also, it's relatively affordable ($1K) and comes highly recommended by TAS and various other online testimonies. I also use the "high level" input as recommended by REL.
This article on the REL site explains it pretty good, why they like the high level input.
https://relsupport.zendesk.com/hc/e...whether-to-use-High-Level-Low-Level-and-LFE-1
https://relsupport.zendesk.com/hc/e...whether-to-use-High-Level-Low-Level-and-LFE-1
Wow, you're planning on four L22's??? That's gonna be a mighty lot of bass! How big is your room? FWIW, my actual AV room is approximately 16' by 25'... but it opens into another room that adds an additional 13' by 21' space (plus a couple of alcoves). While I'm sure that the REL team would prefer that I built a pair of their stacks, they ultimately recommended that I go with a pair of their 212/SX, as they felt it would be needed to adequately 'pressurize' my room.
It's kind of interesting that while both of us seem to be headed in the same direction, that REL and Rythmic came to the same conclusion and pointed us both toward their 2 X 12" subs. Of course I'm choosing the integrated approach while you are going with the RDL converter, but we will likely end up at the same place.
Wait just a second! What happened with the car?
Two stacks is what I'd like to end up with, but by the time I get the second sub it might be evident that only two are enough. But I really want to feel like I'm at a 1970's Deep Purple concert with lots of Marshall stacks all over the place!
The info on Rythmik's web site is not organized well enough to know which amp is being used on some models. So there was some confusion which was cleared up today, at which point they told me there's a new model, E22, which has upgraded drivers, the amp is 800 watts rms instead of 600, couple more features on the amp, and comes in a nicer finish if desired (yes it is), and costs 2/3 more. I asked how to order the new model since it's not on the web site yet, but that was late in the afternoon, so hoping to hear tomorrow.
The thing to keep in mind with Rythmik is there are reasons the price is reasonable. Most of the cabinets are covered in vinyl, with some being upgradeable to piano black or white. The E22 can be ordered in piano black. A lot of the amps do not have high level inputs, they have a mix of features for specific models. The dual driver models are not available with high level inputs, so that's why I need to use an outboard converter. I'm really not worried about the amp qulaity though because it doesn't seem to matter how much audio products cost, they all can have amp problems, just name a company, I don't know of a single company that hasn't had failures - just ask Bob Carver and his failing Amazing Line Source (they're start'n to fizz'n'spark, something in the crossovers). I've been seeing a lot of exploding parts on power amps and speaker amps lately. Lots of blowed up transistors and capacitors ("That blowed up real good!" (SCTV: Farm Film Report skit)). So even though I don't like pudding, that's where the proof will be.
The Rel 212/SX is about 5.3 cubic feet, the Rythmik E22 is about 3.7 cubic feet (based on outside dimensions). They each have two drivers, but 212/SX also has two passives while the E22 is sealed, so the extra weight of the Rel might be the two passive radiators in addition to the larger cabinet, so I gotta believe the cabinet thickness is probably the same. The Rel weighs 30lbs more.
After reading quite a bit of Rel info I decided to try something that is a furthering of what I'm already doing, which is separating LFE into dedicated subs. I've had my system setup for a few months with my subwoofers dedicated to LFE only and using the Expressions for Bass Management. But Rel has it going a step or two farther by having dedicated subs for at least 5 channels and setting up those speakers as Large and using the High Level connection.
The Left/Right each having their own sub, AND the Center having its own sub, all three set as Large and no LFE. The Center dedicated sub makes a lot of sense, and really doesn't need to be very large being that it's mostly voice. So I'm going to pickup a Rel T/5i for the Center channel.
Then Rel says to also use the High Level method for Surrounds. In my system that would mean two more subs, one for Surrounds, one for Rears. Now as crazy as this sounds, it begins to be a little more reasonable because Rel also says to pass the LFE to the Surround sub(s). So for this, I just happen to have a couple subs in the right locations for Surrounds and Rears, so I'm going to try this JUST FOR FUN!
So how is this denoted? I've been using 9.1(3).4 to denote that my system has 9 bed channels, 1 LFE channel with 3 subs, and 4 Height channels (Tops). Adding subwoofers to speakers doesn't increase the channel count, it just makes the "speakers" larger and multi-piece. So maybe it would be 9(3).1(3).4 ?
edit: The main reason for adding subs for the Expressions is to extend bass lower and support bass up to maybe 50Hz or so, which would mean setting the Bass Control on the Expressions to a lower setting. This obviously reduces the muscle needed for those lowest frequencies, which the Expressions do quite well, but if these are relieved a little there "might" be an improvement in clarity? Remains to be heard.
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Chops
Well-known member
Well, for one thing, I wouldn't use a "stack" of subwoofers right along side Martin Logan's, or Magnepan's, or any other kind of dipole loudspeaker. You are essentially putting up a wall along side your speakers. Might as well just plant the speakers right up against the side walls of the room. This is going to greatly effect stereo imaging and close in the sound stage, not to mention even more early reflections right along side the speakers.
Also, if you follow along in what REL is doing with those sub stacks, they are not all crossed over at the same frequency, nor are they all at the same gain setting. As you go up the stack, the crossover frequency is increased and the gain is decreased. They are NOT all set at say 60 Hz @ 1/3 gain.
Example:
Sub 1 (bottom sub) is set at 50 Hz @ 1/2 gain
Sub 2 (middle sub) is set at 100 Hz @ 1/3 gain
Sub 3 (top sub) is set at 150 Hz @ 1/4 gain
So if "that's" what you're wanting to achieve, using those Rhythmic L22's isn't going to do it, and they're going to be nearly 5 feet tall... Right along side your Martin Logan's.
Just as a side note, I have been playing around a bit with my JL subs crossover settings. I had started at around 40 Hz or just below. I now have them at 125 Hz (gains adjusted of course) and the sound is simply amazing. Seamlessly integrated, much larger sound stage, a larger wall of sound and it just makes these old SL3's sound much larger than they are. Vocals are much crisper and cleaner with more body. Instruments are even more natural and life-like. Recording venues as well as my own room feel larger and more open.
I tried this a few months back with the Polk subs but they just got boomy and sloppy sounding. With the JL subs however, because they are so responsive and musical, they can play up that high easily and still be extremely musical. They easily match the speed of the stock SL3's 10" woofer, if not better them. They are a perfect blend with the SL3's and sound just as great with movies as they do music.
Some times, it pays off to experiment and go outside the norm of what's usually done. This is definitely one of those times.
Also, if you follow along in what REL is doing with those sub stacks, they are not all crossed over at the same frequency, nor are they all at the same gain setting. As you go up the stack, the crossover frequency is increased and the gain is decreased. They are NOT all set at say 60 Hz @ 1/3 gain.
Example:
Sub 1 (bottom sub) is set at 50 Hz @ 1/2 gain
Sub 2 (middle sub) is set at 100 Hz @ 1/3 gain
Sub 3 (top sub) is set at 150 Hz @ 1/4 gain
So if "that's" what you're wanting to achieve, using those Rhythmic L22's isn't going to do it, and they're going to be nearly 5 feet tall... Right along side your Martin Logan's.
Just as a side note, I have been playing around a bit with my JL subs crossover settings. I had started at around 40 Hz or just below. I now have them at 125 Hz (gains adjusted of course) and the sound is simply amazing. Seamlessly integrated, much larger sound stage, a larger wall of sound and it just makes these old SL3's sound much larger than they are. Vocals are much crisper and cleaner with more body. Instruments are even more natural and life-like. Recording venues as well as my own room feel larger and more open.
I tried this a few months back with the Polk subs but they just got boomy and sloppy sounding. With the JL subs however, because they are so responsive and musical, they can play up that high easily and still be extremely musical. They easily match the speed of the stock SL3's 10" woofer, if not better them. They are a perfect blend with the SL3's and sound just as great with movies as they do music.
Some times, it pays off to experiment and go outside the norm of what's usually done. This is definitely one of those times.
Yeah, my ML depth i sounds better when the crossover is set up to 100 hz. I was surprised. Thats what the Audyssey program set it for and I tried turning to down to 80 and 60 and got the same results as you. Im just running mine off the sub out LFE.
That might change when I get my new Prodigy panels. Pretty sure Audyssey had the bass way down on the Prodigy speakers because my panels were so weak.
That might change when I get my new Prodigy panels. Pretty sure Audyssey had the bass way down on the Prodigy speakers because my panels were so weak.
No worries! When she is ready, she will get her car. My comment was tied to going for a 'six pack' of REL No. 25's at $45K, which if I had done something like that would have likely put her in a used Yugo!
Actually, she is sort of getting 'her car' as we are both sports car fans and when I asked for her advice on the new center channel sub... she told me to go for the Ferrari Red Ltd Ed T/9i as an accent to the 212/SX's. How could I say no???
Chops
Well-known member
I just wanted to start off with saying that in that last post of mine, that first paragraph sounded a bit harsh. I definitely didn't mean it that way, so I apologize in advance if anyone else sees it that way.
Now back to the regular scheduled program...
Running a single sub and having it crossed over at 100 Hz, I would think it would be drawing attention to itself and would be effecting stereo imaging and such, unless of course you have the sub right in the middle of the front wall.
Didn't sound out of place or harsh Charles. You made a valid point.
Chops
Well-known member
Thank you Brad. Just trying to help out.
Mine is at 80 now and sounds great. Between 80 and 100 is a sweet spot for me and I only have 1.
I hear thee. I'm on a quest to learn'n up about all this since there's almost nothing that explains the hows and whys when it comes to multi-subs for stereo only, whether they be stacks, singles, whatever. Just not enough info to explain it all.
I'm impressed with several ideas Rel is pushing for stereo audio setup and x.1 setup. I stayed up way past my bed time yesterday experiment'n (must be pronounced using a laid back country manner like some of my relatives).
One idea I love - not as much as Rel - is using dedicated subs for each channel or pairs of channels in a system. We all know about Rel pushing a sub for each main speaker, L&R. But they also say to do the same for the Center channel, which makes a lot of sense. But then they maybe go a bit too far by suggesting to do the same for the Surrounds by connecting the Left and Right surrounds to a common subwoofer, also using the high level connection, and then I guess they would recommend doing the same for the Rears.
I have been using my subwoofers for LFE only for several months. The bass management for all Small speakers is sent to my Expressions. The improvement in general system sound quality is very noticeable. LFE needs to be separate as much as possible.
I, like you, am using a high crossover setting for the Motif center. Yesterday I connected my small subwoofer, an old Rel R218, to my Motif center speaker. It's connected only through the high level input. This is where it got interesting, and a bit frustrating. Rel states many times how to adjust the settings when doing this, but it doesn't work for a speaker that is rated for only 73Hz, it's just not low enough. Rel says to set the XO on the sub to its minimum, 30Hz, then increase the gain until it matches the speaker, then increase the XO till it's too much and back off a little. Again, it just doesn't work. Lots of low freq comes through but nothing even close to 73Hz, so there's a gap. Lucky for me I have REW, which made it simple. It ends up that the crossover on the sub is now set to 120Hz, and the gain is set very low where it blends perfectly with the Motif at around 100Hz, which is where the frequency drops like a rock on the Motif. So this is working very well, very happy. Also, I was not aware at how much very low frequency audio comes through the center channel. I always thought it was almost exclusively for voice, it's not. Lots of low bass, music, sounds - but not LFE. So having a dedicated sub for the Center is a really good thing, the audio seems clearer and more natural. I'm hoping to even out a plateau the Motif has when it's calibrated.
Stacks next to the Fronts, yeah, I can see where this might have an issue, but, the stack would be held back a few inches from the face of the Expression. Either way, I'm going to check it out. I love trying things like this. Trying a wacky method on speaker placement as professed by an audio guru is how I ended up with extreme toe-in and loving it.
Regarding dual-driver stacks vs single driver stacks, I like the single driver idea better. And you're correct that Rel uses a method like you describe. That's what I had in mind until Rythmik suggested the two driver model. I'm awaiting some answers to questions I posed a couple days ago, and now I have more questions after becoming confused by seeing conflicting info on their web site.
Rythmik has some info on their site that's the same but for different models, and some images - one of which is wrong for a particular model and conflicts with another which is correct, so it's been very confusing. They need to update their web site to clear up this stuff. After reading their info on the drivers in a couple models I'm now left with doubt that this new E22 is better "for my system and usage" than the "cheaper" version - the L22, mostly based on the drivers used and what Rythmik says about them, saying one is better for music - the driver used in the L22. The downside of the L22 is that it's not available in a better looking finish like the E22. But I care more about performance, so I just want whichever is best for me. I really want to try Rythmik subs simply because so many folks love 'em.
Chops
Well-known member
The nice thing about my JL subs is that they are small. Even on the IsoAcoustics isolators, the tops of the subs are still below the tops of the bass enclosures of the SL3's. And they are positioned about 8" behind the face of the SL3's.
Honestly, if I were to go with Rythmik subs (which I was going to do if these JL subs were going to be too costly to repair), I would only go with the F12G subs for several reasons.
1) They extend down to 14 Hz which is considerably deeper than even the L22.
2) They're small.
3) They use a lighter cone driver designed by Danny Richie of GR-Research, which makes them incredibly fast drivers.
4) They can be had with XLR inputs. (*)
5) These would be perfect for a stereo stack, set up the way REL suggests (although the crossover only goes up to 120 Hz).
These are a perfect match for electrostats, planars, open baffles, fully loaded horns, small drivers, etc, etc.
If I were to get six of these F12G's and use them in stacks, I would end up reinstating my dbx DriveRack Venu360, use the second set of XLR outputs of my preamp to feed the dbx and have the dbx control all six subs (crossover point, gain, phase, timing, etc, etc) via their (*) XLR inputs, bypassing the internal crossovers. Their internal crossovers are quite capable and comprehensive, but the dbx can do everything they can and more, and with more precision, and can all be adjusted from the listening seat in real time.
IF... I were to use four of the L22 subs, I would place one on the outside of each main channel, crossed high, the other two in the rear corners in the back of the room, crossed low for extra bass extension reinforcement.
And keep in mind, in all of these scenarios, I would keep my SL3's playing full range.
Well, no stacks for me! I am officially committed (as in... paid for) a pair of the 212/SX and a T/9i for the center. Likely arriving end of next week or beginning of the following week. Each 212/SX will be placed outside and behind my ESL 15's, with the T/9i obviously close to the center, but set back from my Illusion. The one thing that worries me is originally I intended to bring in a pair of the BF 212's as not only would they better match my ESL 15's, but I liked the idea of the ARC room correction. Now I have given that up, so you will likely see me back up here asking for some help on setting crossovers, etc. As for my rear channels... while I do buy into the REL 3D theater approach, I've got to get all the front side integrated before I really even think much about that...
Congrats!!
The important channels to keep isolated from all other duties for me are LCR. So you got my vote.
I used REW to tune a subwoofer for my center speaker. It was quick to do. Just made a sweep with center speaker only, then one with center and sub together and adjusted as needed for level, crossover, and phase. It only took maybe 8 sweeps to get a smooth blend.
edit: oops, I just realized that model isn't the brand I thought it was. Brain fart. sorry
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My Expressions are operated as Large, full range, exclusively. Never even a thought of cutting off the low end with the processor. Integrating subs with them will probably require adjusting the Bass Control on the back of the Expressions, but I don't want to change anything in the processor.
I asked Rythmik again about which drivers are better for music just yesterday. There's some confusing info on their web site so I need some clarity. I've just been going with the flow of information from Rythmik since some of their products have complete info and others don't. My initial information request was where I mentioned the F12 and L12, and also mentioned that I wanted to end up with stacks, and this is when Enrico suggested the L22.
Today I emailed Rythmik and expressed my interest in preferring the paper drivers. I think Enrico was trying to provide suggestions based on the aluminum cones having "better output" versus what is really intended more for music. Maybe he didn't understand that my preference for a musical sub is as deliberate as it is. I know what capability I want, just need to know which of their products will do what I want.
When I am starting to deal with a company I'm unfamiliar with, I begin with my questions and follow their advice, with as little leading-the-witness stuff as possible going on, to find out what they truly recommend. Then once I have a feel for their product I begin to have a direction based on decisions of my own, but right now I don't have a sense of direction that I can take without more detailed info. In other words, I'm flexible and willing to try what is recommended but I need information. No harm, no foul.
Right now everything is on the table for which model to choose. I'm sure we can work through this once they can get a little more information to me tomorrow.
OK, I am replying to my own post and have made a change in connections for my 4 Depth i subs.
Part of the thread was about running subs in a mono configuration. There was input from members and ML about differentially balanced amps and possibly single ended amps being damaged by connecting both channels to one sub to create the mono signal.
My EE friend pushed me hard to stop this type of connection so I decided to go back to L & R configuration with 2 subs for each.
I moved the sub that had been at the back of the room to the front and placed them as close to the center of the wall as was possible. That gives them a 2' space between them. I left the 2 subs that were on the side walls in the same position. I feed the 2 main subs from the 16ohm taps on my amps at the suggestion of Phil the EE. From there the Belden cable connects to the second sub for each channel.
It meant starting over to find the proper settings on the subs again but I am working that out. So far I have changed the 2 on the front wall from 180 deg. Phase to 90 deg. I moved the low pass from the CLX crossover slope of 30 Hz to 35 Hz. The 25 Hz control went to -4db and the volume to 6.
The side wall subs only have had the crossover moved to 35 Hz and volume to 6 also. The phase is still at 180 deg, 25 Hz control at -6db.
The bass has never so accurate and clean. Going back to the part of this thread about needing subs and how it effects the sound above the crossover point. I sat yesterday for about 4 hours in disbelief that everything about the sound had improved. I would have lost money on that bet as to my room sounding better going back to L & R setup. I can only guess that changes I have made with my room and system in the last couple of years have been the difference. I am at a loss for an accurate explanation and I'm OK with that.
Have you had any issues with your depth i subs? Mine has had several problems and now once in awhile will emit a random period of a static scratching sound. I dont think I will buy another ML sub. Mine had issues right out of the box brand new.
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