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Brian,


Is there a non-plate version of your amps for anyone who wants to place their sub in-wall?
 

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Also Brian,


Did you ever come out with the low impedance 8 inch driver?
 

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Quote:
Originally Posted by sdurani  /t/1214550/official-rythmik-audio-subwoofer-thread/14400_60#post_24475383


Luckily the fourth width mode for his room is 188Hz, so his subs shouldn't be contributing much that high above the crossover point.


The answer was directed at the figure from Dr. Toole's book that you presented with your question. Based on a 20 foot 5 inch wall given in the figure the fourth mode would be at 110 Hz. The subs might contribute to that mode depending on the crossover frequency to the main speakers and its slope.


The 12 foot wall (dimension) has a first mode at 47 Hz and a second at 94 Hz. With an 80 Hz crossover these might be the only modes in this dimension that are affected by the subs. The 94 Hz and higher modes will be fed by the main and any other speakers present which will be harder to control given that the positions of these speakers is likely less flexible. A good position for the main speakers would likely be where the subs are located which creates a conflict. Interesting...
 

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Quote:
Originally Posted by bigguyca  /t/1214550/official-rythmik-audio-subwoofer-thread/14400#post_24479731


The answer was directed at the figure from Dr. Toole's book that you presented with your question. Based on a 20 foot 5 inch wall given in the figure the fourth mode would be at 110 Hz. The subs might contribute to that mode depending on the crossover frequency to the main speakers and its slope.


The 12 foot wall (dimension) has a first mode at 47 Hz and a second at 94 Hz. With an 80 Hz crossover these might be the only modes in this dimension that are affected by the subs. The 94 Hz and higher modes will be fed by the main and any other speakers present which will be harder to control given that the positions of these speakers is likely less flexible. A good position for the main speakers would likely be where the subs are located which creates a conflict. Interesting...

With a 12' x 16' room, it seems like a 100hz crossover makes the most sense, then, in terms of room modes (assuming I am going to position the subs for optimum placement...
 

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Quote:
Originally Posted by nathan_h  /t/1214550/official-rythmik-audio-subwoofer-thread/14400_60#post_24475296


Thanks yes and that's probably the best one can do, but it would be very nice to see the data presented in the same manner as the Harman paper -- which shows how positions impact evenness of response

differently based on different sized rectangular rooms

differently based on different seating locations and

differently in terms of the SPL hit one experiences.



The Harman charts are actual real measurements, down to the centimeter, and down to the actual modeled SPL impact -- taking into account seating locations, sub locations, number of subs.


In some instances, four sibs are better or worse than two subs, depending on the real world size of the room, even when in the same place in a smaller room, and vice versa.


And the Harman data takes seating position into account, and quantifies seat to seat variation so one can judge the relative merits, and then quantifies the SPL impact of the different sub placements and seating placements.


The only thing missing is that their two-sub models don't cover 1/4 length and width placement. Only their four sub models do.


It would be great to have their matlab results for two subs in a room, at the quarter lengths, for various seating configurations -- and see what the seat to seat variation is (since the data shows that) and the SPL hit is.


In the above, it isn't clear if you are discussing calculated or actual, measured results.


Harmon (Welti and Devantier) published measurements taken in three actual room(s) in an AES paper, "Low- Frequency Optimization Using Multiple Subwoofers," showing the results of their Sound Field Management Algorithm. The paper available in the Scientific Publications section of Harmon's website. The paper includes selected results from Welti's work using MATLAB software referenced next.


Harmon (Welti) published extensive MATLAB results developed by varying subwoofer locations, listener locations and room sizes. These results are available in MS Excel format as color plots that are available in the Whitepapers section on Harmon's site. The plots are a supplement to an AES presentation, "Subwoofers, Optimum Number and Locations." (Welti)


Are other Harmon sponsored measured or calculated results available?


It would be nice to have both types of additional data but additions to the MATLAB work seem a lot more practical.
 

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Quote:
Originally Posted by bigguyca  /t/1214550/official-rythmik-audio-subwoofer-thread/14400#post_24479731


Based on a 20 foot 5 inch wall given in the figure the fourth mode would be at 110 Hz. The subs might contribute to that mode depending on the crossover frequency to the main speakers and its slope.
True, though the reason I was more concerned with the width modes than length modes is because his main concern is a single row of seats. Cleaning up the width modes will reduce variation from seat to seat across the row.


IF that row happens to be where the room's 110Hz length mode is peaking, then whatever room correction or equalization he is using will see the same peak in all the seats in that row, making it an easy decision to pull the peak down (i.e., it won't see the peak in some seats and not others).
Quote:
Originally Posted by bigguyca  /t/1214550/official-rythmik-audio-subwoofer-thread/14400#post_24479731


A good position for the main speakers would likely be where the subs are located which creates a conflict.
Personally, I would put the L/C/R speakers at the three nulls of the third width mode, which should keep the first five width modes from being excited. The room correction in his receiver will thank him for that.
 

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Quote:
Originally Posted by bigguyca  /t/1214550/official-rythmik-audio-subwoofer-thread/14430#post_24479939


In the above, it isn't clear if you are discussing calculated or actual, measured results.


Harmon (Welti and Devantier) published measurements taken in three actual room(s) in an AES paper, "Low- Frequency Optimization Using Multiple Subwoofers," showing the results of their Sound Field Management Algorithm. The paper available in the Scientific Publications section of Harmon's website. The paper includes selected results from Welti's work using MATLAB software referenced next.


Harmon (Welti) published extensive MATLAB results developed by varying subwoofer locations, listener locations and room sizes. These results are available in MS Excel format as color plots that are available in the Whitepapers section on Harmon's site. The plots are a supplement to an AES presentation, "Subwoofers, Optimum Number and Locations." (Welti)


Are other Harmon sponsored measured or calculated results available?


It would be nice to have both types of additional data but additions to the MATLAB work seem a lot more practical.

Good clarification. I was responding to the suggestion of relying on Toole's book -- and suggesting that using the later research, first in real rooms + models, then in models, was more useful to me, since real world dimensions and seating locations made a difference with how effective 1/4 wall placement was (for example.) http://www.avsforum.com/t/1214550/official-rythmik-audio-subwoofer-thread/14400#post_24475132


So, to answer your question: I started with the paper (first item in your list) and then moved onto the color excel sheets from the later work (second item in your list). And my post was about wanting more of those color excel charts, for more room/sub location/seat location types -- in particular, a two sub set up, with each sub at a 1/4 the length of the front wall.... since that seems very promising, based, for example, on Toole's rather generic drawing, and it would be great to see it modeled with more rigor.


That is: I would be thrilled with additions to the second set of graphs and analyses. I think the first document helps demonstrate how their modeling actually ends up working in real rooms. So the second, assuming similar correlation exists between models and the real world, is both much easier to expand on (just models) and still very useful (seem to correlate with measured behavior).
 

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Quote:
Originally Posted by sdurani  /t/1214550/official-rythmik-audio-subwoofer-thread/14430#post_24480132


True, though the reason I was more concerned with the width modes than length modes is because his main concern is a single row of seats. Cleaning up the width modes will reduce variation from seat to seat across the row.


IF that row happens to be where the room's 110Hz length mode is peaking, then whatever room correction or equalization he is using will see the same peak in all the seats in that row, making it an easy decision to pull the peak down (i.e., it won't see the peak in some seats and not others).

Personally, I would put the L/C/R speakers at the three nulls of the third width mode, which should keep the first five width modes from being excited. The room correction in his receiver will thank him for that.

That's interesting.


12'wide room.


Screen is 8' wide (2.35:1) AT.


Speakers (LCR) are at 2.2' in from each wall & in the center (to get them just within the viewable area of the screen).


Subs (proposed) at 3' in from each wall.


I don't think third width placement for the LCR works. Too close together....
 

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For a 12-foot wide room, L/R would be 2 feet in from the side walls, giving you an 8-foot spread. Unusable for you since it would put the tweeters behind the 8-foot wide frame of your screen.
 

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Quote:
Originally Posted by klh1790  /t/1214550/official-rythmik-audio-subwoofer-thread/14370#post_24467034


Cool, thanks. I'll try that.

Hey Kyle,


Did you ever figure out your settings and dial in that FV15HP? Sounds like the Marantz SR7008 didnt help? WTF? The output should be F_kn insane in your apartment. Did the new AVR help at all on that level? I'd love to come down again and check it out. just got an Umik-1 from cross spectrum if it helps. From what I heard during the demo (cloverfield and Ender's game) Im completely stumped about the output that everyone describes in this thread for the FV15HP. THeres gotta be something up, cause I know just with my klipsch RF-7II's I can outperform the output (and extension) you produced and I have a 24'x15' room, NO SUBS!!. Astonishing as it sounds, thats how I felt. Just to be clear, I am definitely a prospective buyer of a FV15HP pair and prior to that demo I have never heard a rythmik or any sub at that price level...but after the demo I was left more confused then I was before about what to place in my space. If everythings right, then Im gonna look to the Captivator 2400s or SubM+ master/slave pair price level if I have to to fill my space with the output I'd like to hit. I cant place more than 2 of those in here my wife would flip. Can't DIY cause I just dont have the time. Can anyone help?? Anyone close to southern California to compare to? I wish Ascend in San Clemente had an FV15HP, they only have a F12.
 

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Quote:
Originally Posted by sdurani  /t/1214550/official-rythmik-audio-subwoofer-thread/14430#post_24480191


For a 12-foot wide room, L/R would be 2 feet in from the side walls, giving you an 8-foot spread. Unusable for you since it would put the tweeters behind the 8-foot wide frame of your screen.

Exactly. Much more likely once things are dialed in is at 36". Right now that's the inside edge of the speakers.
 

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Quote:
Originally Posted by DrMJ  /t/1214550/official-rythmik-audio-subwoofer-thread/14430#post_24480557


Hey Kyle,


Did you ever figure out your settings and dial in that FV15HP? Sounds like the Marantz SR7008 didnt help? WTF? The output should be F_kn insane in your apartment. Did the new AVR help at all on that level? I'd love to come down again and check it out. just got an Umik-1 from cross spectrum if it helps. From what I heard during the demo (cloverfield and Ender's game) Im completely stumped about the output that everyone describes in this thread for the FV15HP. THeres gotta be something up, cause I know just with my klipsch RF-7II's I can outperform the output (and extension) you produced and I have a 24'x15' room, NO SUBS!!. Astonishing as it sounds, thats how I felt. Just to be clear, I am definitely a prospective buyer of a FV15HP pair and prior to that demo I have never heard a rythmik or any sub at that price level...but after the demo I was left more confused then I was before about what to place in my space. If everythings right, then Im gonna look to the Captivator 2400s or SubM+ master/slave pair price level if I have to to fill my space with the output I'd like to hit. I cant place more than 2 of those in here my wife would flip. Can't DIY cause I just dont have the time. Can anyone help?? Anyone close to southern California to compare to? I wish Ascend in San Clemente had an FV15HP, they only have a F12.

Just got the 7008 on Monday. I've been messing with that and the FV15HP here and there all week. I'm still lost. It SOUNDS pretty good, but has even less sub output than my old Harman/Kardon avr. But yeah come on down. I was gonna pm you for advice soon anyway seeing as you also have a Marantz avr with Audyssey. I feel like the more I put into this system, the harder it is to get it sounding right. Bummer levels are getting high.
 

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Quote:
Originally Posted by DrMJ  /t/1214550/official-rythmik-audio-subwoofer-thread/14430#post_24480557


Hey Kyle,


Did you ever figure out your settings and dial in that FV15HP? Sounds like the Marantz SR7008 didnt help? WTF? The output should be F_kn insane in your apartment. Did the new AVR help at all on that level? I'd love to come down again and check it out. just got an Umik-1 from cross spectrum if it helps. From what I heard during the demo (cloverfield and Ender's game) Im completely stumped about the output that everyone describes in this thread for the FV15HP. THeres gotta be something up, cause I know just with my klipsch RF-7II's I can outperform the output (and extension) you produced and I have a 24'x15' room, NO SUBS!!. Astonishing as it sounds, thats how I felt. Just to be clear, I am definitely a prospective buyer of a FV15HP pair and prior to that demo I have never heard a rythmik or any sub at that price level...but after the demo I was left more confused then I was before about what to place in my space. If everythings right, then Im gonna look to the Captivator 2400s or SubM+ master/slave pair price level if I have to to fill my space with the output I'd like to hit. I cant place more than 2 of those in here my wife would flip. Can't DIY cause I just dont have the time. Can anyone help?? Anyone close to southern California to compare to? I wish Ascend in San Clemente had an FV15HP, they only have a F12.

DrMJ,


Once you have the UMIK-1 and REW software, can you post a frequency response graph of your subs response from 15Hz to 300Hz, no smoothing? Advise the dB level test signal in the graph, try and target 85dB or above (if it's tolerable or yourself and neighbors). Be sure that Audyssey is OFF on the SR7008. Subs at their current location, mic at Main Listening Position (MLP) and at ear height. Tell us your MLP, LCR and sub placement within the room. What is the height of your room? Advise what the noise floor you measured at.
Quote:
Originally Posted by klh1790  /t/1214550/official-rythmik-audio-subwoofer-thread/14430#post_24480760


Just got the 7008 on Monday. I've been messing with that and the FV15HP here and there all week. I'm still lost. It SOUNDS pretty good, but has even less sub output than my old Harman/Kardon avr. But yeah come on down. I was gonna pm you for advice soon anyway seeing as you also have a Marantz avr with Audyssey. I feel like the more I put into this system, the harder it is to get it sounding right. Bummer levels are getting high.

klh1790,


If DrMJ is in the same neighborhood and proficient with REW, you can ask him to come over and carry out a few measurements - be sure to compensate him accordingly.
Try this experiment, measure the 15Hz to 300Hz as outlined above in the following scenarios:

(a) with your old sub + HK avr;

(b) with your old sub + SR7008;

(c) Rythimik FV15HP + HK avr; and

(d) Rythimik FV15HP + SR7008.


Place the sub (old & Rythmik) exactly where you originally thought it gave the best response. Not sure if you've given room dimensions, LCR position and MLP relative to the room dimensions. The graphs will give help identify the problems you are hearing.


Edit:

See below on my example. Note that the sub is placed at mid-wall along the main length and raised about 2"8' off the floor (due to window bay). The FR says I've got a 62Hz null of about 28dB and this is very audible. I'm getting a Rythmik to help with bass issues.



Room details.
 
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Looks like I've decided on dual F12G's.


Question about the amp options:


I don't want to lose PEQ. I would like to have XLR in and out. If I add the XLR option when ordering, do I lose the PEQ option on the amp? I think so.


XLR is nice for me because my gear closet is is about 30 feet from the where the subs will be (as the cable goes) and while I haven't in the past had any audible signal interference, why tempt fate? I also like the master/slave option.


But PEQ is a must. While I will also have PEQ in the gear rack, that may not always be the case, and my calibrator STRONGLY recommends having it on the sub, too, for maximum adjustability.
 

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Quote:
Originally Posted by nathan_h  /t/1214550/official-rythmik-audio-subwoofer-thread/14430#post_24481420


Looks like I've decided on dual F12G's.


Question about the amp options:


I don't want to lose PEQ. I would like to have XLR in and out. If I add the XLR option when ordering, do I lose the PEQ option on the amp? I think so.


XLR is nice for me because my gear closet is is about 30 feet from the where the subs will be (as the cable goes) and while I haven't in the past had any audible signal interference, why tempt fate? I also like the master/slave option.


But PEQ is a must. While I will also have PEQ in the gear rack, that may not always be the case, and my calibrator STRONGLY recommends having it on the sub, too, for maximum adjustability.

Why F12G? If for music exclusively, I find my F12SE/PEQ3 ideal for both music and cinema.


EDIT: To clarify, with my system music has always been my highest priority.
 

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Quote:
Originally Posted by Iain-  /t/1214550/official-rythmik-audio-subwoofer-thread/14430#post_24481738


Why F12G? If for music exclusively, I find my F12SE/PEQ3 ideal for both music and cinema.


EDIT: To clarify, with my system music has always been my highest priority.

I'm agreeing with you, I need the parametric EQ, even if it means I cannot have XLR inputs.
 

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Quote:
Originally Posted by nathan_h  /t/1214550/official-rythmik-audio-subwoofer-thread/14430#post_24482084


I'm agreeing with you, I need the parametric EQ, even if it means I cannot have XLR inputs.

If longer cable run is an issue, use BJC LC-1:
http://www.bluejeanscable.com/store/subwoofer/index.htm


I've used a 10 metre run of it on my F12SE for the past two years, without issue. It's well screened and low capacitance.
 

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Quote:
Originally Posted by nathan_h  /t/1214550/official-rythmik-audio-subwoofer-thread/14430#post_24482084


I'm agreeing with you, I need the parametric EQ, even if it means I cannot have XLR inputs.

Both XLR2 and XLR3 have PEQ, and both have unbalanced LINE and LFE IN on RCA jacks. XLR2 has balanced in and out, though the out is HPF. XLR3 has SOURCE and LFE in on XLR's, but no OUTPUT's.
 

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Quote:
Originally Posted by BDP24  /t/1214550/official-rythmik-audio-subwoofer-thread/14430#post_24482835


Both XLR2 and XLR3 have PEQ. XLR2 has balanced in and out, though the out is HPF. XLR3 has balanced and RCA in, including LFE.

Good to know. So in the F12G options, I cannot accidentally choose an amp lacking parametric EQ? Sounds like all options have it.
 
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