AudioCircle
Industry Circles => GR Research => Topic started by: Ern Dog on 3 Jan 2016, 05:06 pm
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I'm in need of a sub for my 2 ch music/HT rig and I'll eventually get dual subs. I just ordered a Rythmik GR research sub. I'm wondering how this sub compares to the Rythmik standard version with the aluminum drivers. I'm guessing the aluminum offers less distortion because of the rigidness and the paper cone sound more natural sounding?
What I'm looking for is clean tight bass that will fill in the last couple octaves that my main speakers don't capture. I like realistic sounding bass. I have some live cd's that don't sound real without a bass foundation, for example the Eagles 'Hell freezes over' or Dead can Dance new live cd. I sometimes like to listen loud too. I also love classical music and jazz, so the subs need to do it all.
I'm interested in people's thoughts about these two sub designs who have heard them both.
Thanks,
Ernie
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I forgot to add that my listening room is 23'x13.5'. My main speakers are Coincident Total Eclipse II. I also have some room treatment, 2 Gik corner traps positioned in the front corners, and 2 Gik panels to capture the 1st reflection points.
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Nice size room and speakers. I have heard the aluminum hits harder and just as fast in lower regions. Either way you should be good.
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Link to the speakers the OP owns:
http://www.coincidentspeaker.com/total_eclipse.htm
Best,
Anand.
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Nice speakers! 8)
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Thanks guys.
Somebody here must have heard both subs?
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The person I shared with you did and that was the opinion. If you already ordered the GR version why worry about it. The time to have asked was before the purchase. My guess is the GR might blend better with your speakers.
Rocket_Ronny
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Thanks guys.
Somebody here must have heard both subs?
From the Rythmik website: "The main performance difference is in the drivers. F12G uses a paper driver designed by GR Research. The paper driver is lighter than our standard aluminum drivers and has a more extended response. It can handle a higher crossover point, however, this is only significant when crossing above 80 Hz If a higher crossover point is desired, F12G is the subwoofer of choice."
Best,
Anand.
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Here is the entirety of what Anand posted from the Rythmik website: The main performance difference is in the drivers. F12G uses a paper driver designed by GR Research. The paper driver is lighter than our standard aluminum drivers and has a more extended response. It can handle a higher crossover point, however, this is only significant when crossing above 80 Hz If a higher crossover point is desired, F12G is the subwoofer of choice. Please note: when crossing this high, localization can become an issue and dual subwoofers are recommended. Regarding the lower mass, this results in slightly better dynamics at low to moderate output levels. The downside with the paper cone is that it is not as stiff as our aluminum drivers. Our standard F12 subwoofer features the same driver and amplifier as our signature edition, but has a vinyl veneer.
I obviously like the lighter weight paper based cone. It does offer a more natural sound to it. And unless you are going to be pushing it constantly to the X-Max it really doesn't give up anything to the Aluminum version.
You made a good choice with your purchase. You'll really enjoy it.
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Hello, Ernie.
I have not heard the aluminum cone, but I do own a single F12G. I think it is a tremendously good sub and a great deal for the price. As good as it is and as good as it sounds, I personally think you will be happier with two of them (or more if you subscribe to the Swarm theory). I've used mine in three rooms - ~15'L X 12'W X 8.5'H, 13.5' X 29' X 8.5', and a huge cathedral ceiling family room/kitchen/breakfast nook.
No time to finish....will add later...
Okay, more time now.
In the smallest room there was never any doubt that one sub was enough. The room was filled with low Hz bass in a very pleasing way.
In the cavernous family room, I struggled to find an ideal location for just one sub. There were just too many cubic ft of open space to fill. It wasnt the sub's fault because I never got my L/R speaker to sound very good there either. I suspect my family room was deliberately designed to be the 'acoustic room from Hell'. The architect ought to be shot. I briefly tried using two subs (an F12G and a PSB 12" sub) and realized even this was inadequate. My wife wasn't quite ready for a subwoofer swarm invasion, so I never pursued multiple subs in that room. The only speaker that sounded 'right' in this room was my Ancora CC.
In my 13.5' X 29' room (formal living room/dining room), the single F12G was adequate, but everything sounded better when I added the PSB sub. My two-channel system sounds best in this space.
Three things kept me from running out to buy a second F12G: my deciding I 'had to' get a pair of the Rythmik double eight subs (increased WAF appeal), but never happened due to unfortunate investment decision; my relocating to Taiwan for 6 months (had planned to buy a pair of double eights for Taiwan until I discovered the 21% import duty!), and my 'discovering' the GR Research OB sub sound at Captainhemo's (Jay) home - six hours of wonderful music, food and conversation. Simply magical.
So do consider buying two F12G subs, but start with one. Perhaps I could sell you mine down the road once my future living location is clearer.
Michael
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Sorry, I haven't heard the aluminum cones either, but I have GR drivers running in three different rooms (sounds excessive), dual open-baffle in one and a single sealed in the others, transformative in every one.
I have also come to appreciate Danny's experience and willingness to share it -- I certainly wouldn't worry about your purchase, and just look forward to completing the pair :).
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Thanks guys!
I'm excited about this!
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I am still confused about the difference in paper vs alu drivers (among other things).
Let me try to put it this way, my plan is to use two F12 (sealed) subwoofers to augment Harbeth P3ESR and will be used 90% for the music. The crossover FQ will be lower than 80Hz (I cannot apply High pass so P3ESR will be run full range).
I wondered what would be the better match to Harbeth, a paper or alu driver?
One generic question about subwoofers too. As they will be placed on the front wall some 3 ft behind the main speakers, there will obviously be some timing issues. And, as I cannot delay the main speakers would phase correction be enough or the integration simply won't work and I shouldn't waist my time in trying to integrate them?
I have also read somewhere that the box sizes are not the same for F12G and F12, correct?
Also: "Light weight paper cone with foam surround for superior dynamics". -> What is typical life expectancy for the foam?
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These servo-controlled subs from Brian and Danny are in my opinion the best out there for the money. They simply disappear leaving only the music. Even after years of use I'm surprised by their performance. No bloat. No boom unless there's supposed to be boom. I often forget they're working until I turn them off and the foundation they provide vanishes.
They're also great for movies and TV!
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As a dealer over the years showing our wares at the audio shows to date I have yet to experience better bass than what Danny offers. When we used his design at Capitol Audiofest with the BG Radia speakers we received rave reviews. As soon as we put an Organ or bass recording on the room was filled.
One will never go wrong with a GR OB sub. Never ! KABOOM for the buck as well.
charles
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The paper based drivers have more of a natural sound. The paper drivers offer a little better resolution, are slightly faster, are a little cleaner, and have a little better dynamics. They really don't give up anything to the metal cone drivers.
And the foam surrounds will last a lifetime. They are not like the old foam products of many years ago that rot and fall to pieces.
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I've heard a ton of subs and I've built some subs myself. GR Research are the best I've heard, period. They aren't the loudest I've heard. That would be the 12 Shiva's Dancing that my friend TomW built into an Infinite Baffle and used his entire basement as an enclosure for the 12 Shiva woofers and cut a hole in the floor of his home theater and vented the base into the HT room from the basement below. That was some crazy sh!t. But the GR Research subs sound way better. And hey, if you need more output, just buy another one. Most rooms will only need one, though.
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The paper based drivers have more of a natural sound. The paper drivers offer a little better resolution, are slightly faster, are a little cleaner, and have a little better dynamics. They really don't give up anything to the metal cone drivers.
And the foam surrounds will last a lifetime. They are not like the old foam products of many years ago that rot and fall to pieces.
That was an answer which sold two F12G, Danny ;) Thanks.
I do have one concern so one more question, please.
I would like to pair two F12G subs with Harbeth P3ESR, but my integrated amp cannot neither delay the signal nor cut off low FQ to main speakers. Based on this I would only be able to do some phase adjustment on the subwoofer, but the sound from the subwoofers would always be behind in time due their placement behind the main speakers. The main speakers are some 3ft from the front wall, 4.5ft apart and I listen some 4ft from the speakers' plane (near field). The subs would be be few inches from the front wall, behind the speakers, but outside of them.
In case I cannot change the amp, should I even bother trying to integrate those subs with P3ESR?
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If you look at the specs for the Rythmik A370PEQ servo amp, it has both crossover and phase controls along with a single PEQ. That is in the F12G servo sub.
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If you look at the specs for the Rythmik A370PEQ servo amp, it has both crossover and phase controls along with a single PEQ. That is in the F12G servo sub.
The thing is I can only send line level signal and speakers signal from the amp at the same time, but I cannot get it back to input as the input is used by let's say CD player (it is an integrated amp). So, I cannot send the line out and bring it back as for input. The only way I can do it is by sending it to the sub and speakers at the same time.
Given the fact main speakers are in front of the subs, the sound from subs will always lag behind in time.
Maybe I don't understand the matter well enough. I am trying to comperhand if I correct the phase at crossover FQ, the time will still be delayed from the subwoofer compared to the mains.
In short, I believe I can fix the phase, but not the time. Hence, my concern, is it even worth trying to integrate subs and mains given this limitation?
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The A370PEQ Delay/Phase control lets you adjust the time delay or phase at the crossover frequency for the sub. That is what the 0mS to 18mS range means on the control means. The high level inputs will take the integrated outputs. Even though they are behind the speakers at those frequencies, but wavelengths are very long and phase will get you close.
You can use PC or MAC with a program like Room EQ Wizard and a measuring mic for setup for best bass response running the sub with the main speakers.
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The A370PEQ Delay/Phase control lets you adjust the time delay at the crossover frequency for the sub. That is what the 0mS to 18mS range means on the control means.
HAL, I appreciate your effort, however, I don't think you understood well what my concern was (not sure if it is valid).
If the subwoofer is placed behind the main speakers, the sound coming from it would be delayed compared to the main speakers. By using the knob which delays the signal from 0ms to 16ms I will be able to put the sound in phase, but I will delay it even more.
My understanding is the mains and sub will end up being in phase, but the sound from the sub will be delayed by a cycle, two cycles, not sure.
That's why I posted the question whether this time difference is the sound arriving to the listener position between the mains and subwoofer will be noticeable or not (even though sounds of both sources are "in phase").
I hope this makes more sense now. I will repeat, I am not claiming anything just trying to comperhand whether it is worth trying to integrate my mains with the subs or not.
Thanks!!!
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Yes, I understand the sound of the subs is delayed being behind the mains. That is very typical. The phase control will do a lot to align the two speakers. It is not perfect, but much better than no adjustment. The wavelengths you are using at the crossover frequency are very long, so phase adjustments get close.
You are correct that the best is adding time delay to the mains to match the subs, but that would not work with an integrated that does not have a user input connection between the preamp and power amp sections and splitting the signal with time delay to the mains, and feed the servo subs line level inputs.
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Keep in mind that your speakers crossover also causes a delay. So they may not be near as in front of the woofers as you think. You may actually have to add delay. And the length of the wavelength of 40Hz is about 28 feet long. So a three foot time delay at those frequencies are not much of a phase rotation.
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Thanks for the clarification!!
As P3ESR has -3db@75Hz, and I can only send line out to the subwoofer, would it be better if I purchased something like this http://www.parts-express.com/harrison-labs-fmod-inline-crossover-pair-70-hz-low-pass-rca--266-252 , plug them between the line out and line in and set the amp to AVR/12?
My line outs are one L and one R, do I need to use some splitter in case of two subs or I simply connect line out L to L of 1st subwoofer and line out R to L of 2nd subwoofer?
Also, P3ESR has 12db roll off and sub will have 24db will this be hard to integrate?
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This discussion got me to thinking.
Let's say the crossover point between mains and subs is 80Hz. What if you could dial in an oscillator with an 80 Hz sine wave and send the tone to both main and sub at the same time? With microphones set up in front of each and outputs routed to an oscilloscope, wouldn't it be possible to sync the two signals into looking like a single sine wave by adjusting the A370PEQ (or other) phase control? And wouldn't this be more accurate than trying to set the system up by ear?
My friend, Greg chimed in: Also you could eliminate possibility of microphone differences by using only a single microphone. For that case you could store and display the first waveform (as reference), after which you could watch the 2nd waveform (real-time, superimposed on the screen). You would then adjust phase control for zero phase between the real-time waveform vs. stored reference waveform.
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There is one other thing I cannot find the information for, and that's how sensitive the volume knob is, so anyone's comment is welcome.
P3ESR's sensitivity/m is as follows:
1w 83dB
2w 86dB
4w 89db
8w 92dB
16w 95 dB
32w 98 dB
I only found the info GR driver is 88dB. If I understand this well, then I would need to turn the volume knob on the amp to use a bit less then 4w to level the volume up with main soeakers, and in case of two subs even less.
Will this be hard to do given the amps power of 370W?
Actually, how does the vokume knob work is it linear?
Thanks!!
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And then I thought, why would you need an oscilloscope? Why not just reverse the leads on the sub and listen for a null by adjusting the phase control knob?
I probably should try this for myself before spouting off , but I'd like to hear what you guys think.
To recap:
1. Place the mains and subs where you want to
2. Reverse the leads on one of the the subs so that it is 180 degrees out of phase with its main
3. Send a tone at the crossover point to both the main and the sub (say, 80 Hz)
4. Use the phase control to null out the sound.
5. If you run out of travel on the phase control knob, move the sub and try again.
6. Do the same for the other main/sub combo
Should this work? If not; why not?
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Thanks for the clarification!!
As P3ESR has -3db@75Hz, and I can only send line out to the subwoofer, would it be better if I purchased something like this http://www.parts-express.com/harrison-labs-fmod-inline-crossover-pair-70-hz-low-pass-rca--266-252 , plug them between the line out and line in and set the amp to AVR/12?
My line outs are one L and one R, do I need to use some splitter in case of two subs or I simply connect line out L to L of 1st subwoofer and line out R to L of 2nd subwoofer?
Also, P3ESR has 12db roll off and sub will have 24db will this be hard to integrate?
Are you talking about using the line out RCA outputs on the servo amps?
Also, the FMod values can be a bit misleading. They advertise a crossover value, but the actual crossover value varies a LOT depending on the input impedance of your amp. So it may or may not work as advertised. Also, the quality level of those are mediocre at best.
And you will never need to add something like that to the servo amp. The amp already has crossover control functions right there on the amp.
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This discussion got me to thinking.
Let's say the crossover point between mains and subs is 80Hz. What if you could dial in an oscillator with an 80 Hz sine wave and send the tone to both main and sub at the same time? With microphones set up in front of each and outputs routed to an oscilloscope, wouldn't it be possible to sync the two signals into looking like a single sine wave by adjusting the A370PEQ (or other) phase control? And wouldn't this be more accurate than trying to set the system up by ear?
My friend, Greg chimed in: Also you could eliminate possibility of microphone differences by using only a single microphone. For that case you could store and display the first waveform (as reference), after which you could watch the 2nd waveform (real-time, superimposed on the screen). You would then adjust phase control for zero phase between the real-time waveform vs. stored reference waveform.
I set them up using measurements from our Clio system. It just takes a few minutes to dial the subs and main speakers in so that they are in phase.
But once you know what to listen for you can also dial them in by ear pretty quick too.
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There is one other thing I cannot find the information for, and that's how sensitive the volume knob is, so anyone's comment is welcome.
P3ESR's sensitivity/m is as follows:
1w 83dB
2w 86dB
4w 89db
8w 92dB
16w 95 dB
32w 98 dB
I only found the info GR driver is 88dB. If I understand this well, then I would need to turn the volume knob on the amp to use a bit less then 4w to level the volume up with main soeakers, and in case of two subs even less.
Will this be hard to do given the amps power of 370W?
Actually, how does the vokume knob work is it linear?
Thanks!!
You are making this way more difficult than it is. This is actually very easy.
Play your main speakers to a constant level then turn up the volume knob on the servo amp until the levels match. You don't even need a meter. I use a reference song that gets me there in about 15 seconds.
And driver sensitivity is irrelevant.
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And then I thought, why would you need an oscilloscope? Why not just reverse the leads on the sub and listen for a null by adjusting the phase control knob?
I probably should try this for myself before spouting off , but I'd like to hear what you guys think.
To recap:
1. Place the mains and subs where you want to
2. Reverse the leads on one of the the subs so that it is 180 degrees out of phase with its main
3. Send a tone at the crossover point to both the main and the sub (say, 80 Hz)
4. Use the phase control to null out the sound.
5. If you run out of travel on the phase control knob, move the sub and try again.
6. Do the same for the other main/sub combo
Should this work? If not; why not?
It is easier than that. You don't even have to reverse the wiring on the subs. You can just turn the dial to do the same thing. You can create a complete null or perfect alignment just by turning the knob.
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Are you talking about using the line out RCA outputs on the servo amps?
Also, the FMod values can be a bit misleading. They advertise a crossover value, but the actual crossover value varies a LOT depending on the input impedance of your amp. So it may or may not work as advertised. Also, the quality level of those are mediocre at best.
And you will never need to add something like that to the servo amp. The amp already has crossover control functions right there on the amp.
Thank you very much for spending your time in answering my questions, I truly appreciate it.
My amplifier has L and R line level outputs so L would be used to be connected to the left subwoofer and R would be used to connect it to the right subwoofer.
I just wondered where exactly should these be connected to the subwoofer inputs, L to L of left subwoofer's RCA input and R to L of right subwoofer's RCA input?
In regards to the crossover, I am just worried not to mess up the clarity of Harbeth. P3ESR are specified as -3db @75Hz and they roll off at 12db/octave. On the other hand subwoofer crossover switch can be set to 80Hz (I assume -3db), but with the slope of 24db/octave. I am worried there will be too much overlap between the two and I would need to use the PEQ to level it up (in that case I would not be able to use it at some other frequency which I would probably need due to the room modes). Hence, my idea of using FMods. Given your comments, I understand FMods wouldn't be a wise choice.
Ideally, I would need to have an amp which also had an option of 80Hz HPF which would relieve the mains of low freq load, but unfortunately I don't have such an option.
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Thank you very much for spending your time in answering my questions, I truly appreciate it.
My amplifier has L and R line level outputs so L would be used to be connected to the left subwoofer and R would be used to connect it to the right subwoofer.
I just wondered where exactly should these be connected to the subwoofer inputs, L to L of left subwoofer's RCA input and R to L of right subwoofer's RCA input?
You can use either the left of right input on either amp. It won't matter.
In regards to the crossover, I am just worried not to mess up the clarity of Harbeth.
The clarity of the Harbeth? Aren't these the speakers with lightly built un-braced boxes.
P3ESR are specified as -3db @75Hz and they roll off at 12db/octave. On the other hand subwoofer crossover switch can be set to 80Hz (I assume -3db), but with the slope of 24db/octave. I am worried there will be too much overlap between the two and I would need to use the PEQ to level it up
The controls on the plate amp will allow you to do anything you want with the response of the servo woofer. Just leave the control in the middle EXT/12 position and you simply have 12db per octave slopes controlled infinitely but the crossover control knob. You then can add an additional 12db per octave slope at 80Hz or 50Hz with the flick of a switch.
(in that case I would not be able to use it at some other frequency which I would probably need due to the room modes). Hence, my idea of using FMods. Given your comments, I understand FMods wouldn't be a wise choice.
You won't need the PEQ of blending the subs to your main speakers.
And yes, never add an FMod inline with the plate amp.
Ideally, I would need to have an amp which also had an option of 80Hz HPF which would relieve the mains of low freq load, but unfortunately I don't have such an option.
That's easy. Just use a high quality capacitor like a Sonicap Platinum as a high pass filter for your amp.
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Harbeth and clarity :) ...well, what I thought was the change in sound due to the fact both speakers would play same frequencies. Anyhow, I read somewhere AVR was used with the AMP which has bass management and totally ignored the crossover knob. :duh: I guess I am back on the track.
So if one sets the switch to AVR the crossover knob is what determines the line in lowpass frequency, but if one switches to 50Hz or 80Hz on the line in lowpass than the crossover knob becomes irrelevant?
Regarding the high pass filter, the problem is it is an integrated amp. The only way would be to put something before the speakers, but I am not sure if this is wise as I would actually add something to the crossover.
Thanks a lot. I don't think there any other reason not to get these subs. :thumb:
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Harbeth and clarity :) ...well,
You mean this speaker?
(http://www.6moons.com/audioreviews/harbeth3/5.jpg)
what I thought was the change in sound due to the fact both speakers would play same frequencies.
You cross them over to one another where they are each 6db down. That will make your response flat.
Anyhow, I read somewhere AVR was used with the AMP which has bass management and totally ignored the crossover knob. :duh: I guess I am back on the track.
Some of those receivers will send a 12db per octave sloped output to the sub outs. So using the center position on that switch adds just a 12db per octave slope controlled by the crossover control knob. So you get a 24db per octave slope depending on where you set the control.
So if one sets the switch to AVR the crossover knob is what determines the line in lowpass frequency, but if one switches to 50Hz or 80Hz on the line in lowpass than the crossover knob becomes irrelevant?
No, the crossover knob is always active and is infinitely adjustable with a 12db per octave slope.
Regarding the high pass filter, the problem is it is an integrated amp. The only way would be to put something before the speakers, but I am not sure if this is wise as I would actually add something to the crossover.
In that case the only way to filter the lows off of your speakers is to add a coupling cap to the input on the amplifier internally.
Thanks a lot. I don't think there any other reason not to get these subs. :thumb:
You'll love the subs.
I can also help you upgrade those speakers. If you like the speakers and want to keep them then we can upgrade the crossover parts (the stock ones are really poor), binding posts, wire, and line the cabinets with No Rez. Clarity can be increased significantly on that model and across the board. It will improve the bass response and imaging as well.
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Thank you for all the details. I think the speakers are intentionally made "without" bracing. I am not sure I would like to change this.
I guess the crossover could be updated, there's always room for make crossover better, but for now the only thing I am willing to invest in is the lower two octaves from where the speakers roll off. I do appreciate your offer, though.
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Thank you for all the details. I think the speakers are intentionally made "without" bracing. I am not sure I would like to change this.
I guess the crossover could be updated, there's always room for make crossover better, but for now the only thing I am willing to invest in is the lower two octaves from where the speakers roll off. I do appreciate your offer, though.
Yeah those speakers are known for cabinet resonances in several ranges. Some feel like the resonances add a pleasing effect. But in reality it is noise that is not part of the input signal. And removing it can be quite an improvement. A sheet of No Rez will do wonders for them.
Subs, upgrades of any kind, etc. I'll help you with any of that whenever you're ready.
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Subs, upgrades of any kind, etc. I'll help you with any of that whenever you're ready.
Thank you very much, I'll certainly keep this in my mind.
Cheers!!!