Official JTR Speakers Subwoofer Thread - Page 311 - AVS Forum | Home Theater Discussions And Reviews
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post #9301 of 14521 Old 08-03-2018, 12:28 PM
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Originally Posted by beastaudio View Post
Should be fine, albeit I never used that way previously so I can't comment on the results and if they are any different than adjusting the actual trim of the subs in the manual setup menu. Maybe @jdsmoothie can chime in
Thanks for letting me know about the speaker and sub level adjustments by input using the Options button. I have tweaked my Apple TV and Roku to bump up my Atmos ceiling speakers and I bumped up my sub on my Panasonic UB900 input for movies.

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post #9302 of 14521 Old 08-03-2018, 01:05 PM
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Originally Posted by farsider3000 View Post
Thanks for letting me know about the speaker and sub level adjustments by input using the Options button. I have tweaked my Apple TV and Roku to bump up my Atmos ceiling speakers and I bumped up my sub on my Panasonic UB900 input for movies.
Cheers Mate! It's a great feature that is a little known shortcut.
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post #9303 of 14521 Old 08-03-2018, 09:21 PM
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Did your last bass hum with the cables you are using now?
I am also curious if you fixed the flat bass response and are hearing thundering lows from that CAP 2400ULF.
No, my last subwoofer did not have that hum. Am using the same RCA cable too. WIll need to try and figure out the cause of the hum. I haven't fixed the flat bass response as of yet too, going o work on it this weekend.
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post #9304 of 14521 Old 08-03-2018, 10:41 PM
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OK, Holy Crap did I have a revelation today!


I re-tuned my 2X4 HD EQ tonight and the attached is the result. The green line is the un-treated response (no EQ), the red is after the EQ that REW created for me. There is a slight increase to the red line at lower frequencies, that is exactly what I configured in REW.



I left the subs disabled in my tower speakers and I must say, my system has NEVER sounded more balanced and more powerful! The desire for a second 2400 to balance things out has disappeared.


Last nit-pick to investigate is the severe dip just above 80 hz but to be honest, the balance of the remainder sounds much better, even with the 80 hz dip.


Going to watch John Wick 2 now to see if the gunshots can draw actual blood!
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post #9305 of 14521 Old 08-03-2018, 10:54 PM
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Originally Posted by schwaggs View Post
OK, Holy Crap did I have a revelation today!


I re-tuned my 2X4 HD EQ tonight and the attached is the result. The green line is the un-treated response (no EQ), the red is after the EQ that REW created for me. There is a slight increase to the red line at lower frequencies, that is exactly what I configured in REW.



I left the subs disabled in my tower speakers and I must say, my system has NEVER sounded more balanced and more powerful! The desire for a second 2400 to balance things out has disappeared.


Last nit-pick to investigate is the severe dip just above 80 hz but to be honest, the balance of the remainder sounds much better, even with the 80 hz dip.


Going to watch John Wick 2 now to see if the gunshots can draw actual blood!
Nice!!!
Can you post up a center + sub graph? chances are that dip may be filled in

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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post #9306 of 14521 Old 08-04-2018, 02:00 AM
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Originally Posted by mir3acles View Post
No, my last subwoofer did not have that hum. Am using the same RCA cable too. WIll need to try and figure out the cause of the hum. I haven't fixed the flat bass response as of yet too, going o work on it this weekend.
If the only change is the CAP 2400 sub then it seems to reason that the 2400 is the source of the hum.

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post #9307 of 14521 Old 08-04-2018, 08:19 AM
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Originally Posted by schwaggs View Post
OK, Holy Crap did I have a revelation today!


I re-tuned my 2X4 HD EQ tonight and the attached is the result. The green line is the un-treated response (no EQ), the red is after the EQ that REW created for me. There is a slight increase to the red line at lower frequencies, that is exactly what I configured in REW.



I left the subs disabled in my tower speakers and I must say, my system has NEVER sounded more balanced and more powerful! The desire for a second 2400 to balance things out has disappeared.


Last nit-pick to investigate is the severe dip just above 80 hz but to be honest, the balance of the remainder sounds much better, even with the 80 hz dip.


Going to watch John Wick 2 now to see if the gunshots can draw actual blood!
Now go back and connect the subwoofers in your towers to another output of the 2x4HD and overlay the 2400, left main sub, right main sub, both left+right main subs together, and then all 3 together. Depending on the responses you see, you may have a lot of options to tinker with.

Point here is to use the woofers in your speakers as additiona subwoofers and your speakers as small speakers. After measuring you should probably high pass the subs in your speakers in the 30-40Hz range to make sure they don't limit the system. Which model speakers are they again? Based on the response you saw previously with the LFE+ main, I expect they might significantly fill in that upper bass dip (~50Hz) without having to apply so much EQ and put the subs in your towers to some practical use. The connection to your receiver should remain the same with a single subwoofer connection to the 2x4 and then route the input signal to all 3 subwoofers. If it makes connection easier, you could also combine both tower subwoofers off a single RCA from the 2x4HD.

Here's your last measurement so we have things visible in one spot:

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post #9308 of 14521 Old 08-04-2018, 02:30 PM
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Originally Posted by Mark Seaton View Post
Now go back and connect the subwoofers in your towers to another output of the 2x4HD and overlay the 2400, left main sub, right main sub, both left+right main subs together, and then all 3 together. Depending on the responses you see, you may have a lot of options to tinker with.

Point here is to use the woofers in your speakers as additiona subwoofers and your speakers as small speakers. After measuring you should probably high pass the subs in your speakers in the 30-40Hz range to make sure they don't limit the system. Which model speakers are they again? Based on the response you saw previously with the LFE+ main, I expect they might significantly fill in that upper bass dip (~50Hz) without having to apply so much EQ and put the subs in your towers to some practical use. The connection to your receiver should remain the same with a single subwoofer connection to the 2x4 and then route the input signal to all 3 subwoofers. If it makes connection easier, you could also combine both tower subwoofers off a single RCA from the 2x4HD.

Here's your last measurement so we have things visible in one spot:

Thanks for the suggestion Mark! I'm having a ton of fun watching movies with just the 2400! I'll try your suggestion later tonight or tomorrow morning.



I have a Pioneer SC-97 which has dual sub woofer outputs. Would you suggest I run the output of the 2400 on the primary output and the ancient Polk 2000i subs on the second? This way I get easily adjustable gain and delay settings for each from the AVR (adjusting the 2X4 is a bit of a pain). I can connect sub output 2 into input 2 on the 2X4 and separate outputs to each tower which allows for separate EQ for R and L for maximum flexibility.


Thoughts?
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post #9309 of 14521 Old 08-04-2018, 06:39 PM
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Originally Posted by schwaggs View Post
Thanks for the suggestion Mark! I'm having a ton of fun watching movies with just the 2400! I'll try your suggestion later tonight or tomorrow morning.

I have a Pioneer SC-97 which has dual sub woofer outputs. Would you suggest I run the output of the 2400 on the primary output and the ancient Polk 2000i subs on the second? This way I get easily adjustable gain and delay settings for each from the AVR (adjusting the 2X4 is a bit of a pain). I can connect sub output 2 into input 2 on the 2X4 and separate outputs to each tower which allows for separate EQ for R and L for maximum flexibility.

Thoughts?
You are best off just using one output from the Pioneer, and do all of the blending in the 2x4. You have to connect the computer to set routing and filtering, so I'd go with that as well. You can always pick up a 15' USB extension if that helps. After measuring to see if the subs deliver much energy to that 50Hz recession, you can put say a 2nd order (12dB/oct) high pass on them around 40Hz, and play with level and delay to see if they offer any help. Unless the 2400 is much closer than the mains, you will probably want to add the delay to the L/R subs. It's somewhat unlikely you would want to set the pair at different levels or EQ separately, and definitely not if your room is reasonably symmetrical left-right.

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post #9310 of 14521 Old 08-05-2018, 09:01 AM
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Originally Posted by Mark Seaton View Post
Now go back and connect the subwoofers in your towers to another output of the 2x4HD and overlay the 2400, left main sub, right main sub, both left+right main subs together, and then all 3 together. Depending on the responses you see, you may have a lot of options to tinker with.

Point here is to use the woofers in your speakers as additiona subwoofers and your speakers as small speakers. After measuring you should probably high pass the subs in your speakers in the 30-40Hz range to make sure they don't limit the system. Which model speakers are they again? Based on the response you saw previously with the LFE+ main, I expect they might significantly fill in that upper bass dip (~50Hz) without having to apply so much EQ and put the subs in your towers to some practical use. The connection to your receiver should remain the same with a single subwoofer connection to the 2x4 and then route the input signal to all 3 subwoofers. If it makes connection easier, you could also combine both tower subwoofers off a single RCA from the 2x4HD.

Here's your last measurement so we have things visible in one spot:

I connected everything up last night and took some measurements. I ran separate outputs from the 2X4 into each sub (2400, Left, Right).

The tower speakers are along the screen wall and flank my 120" screen which is centered on the screen wall. Each speaker is about 38 inches from each side wall. I have ZERO flexibility in this setup, there are doorways between the speakers and side walls. The 2400 is against the front wall in the exact center of the wall. MLP is 2 seats centered in the room (each MLP is off center by the width of a chair, if that makes sense).

I turned on 1/48 smoothing to make the above 80 response look less confusing. I can post non-smoothed graph if preferred. It really has little to no effect on the lower parts of the graph.

Subs without EQ
Blue - Towers
Yellow - 2400
Purple - combined

One HUGE takeaways from this for me: The 32hz spike I have been fighting for over a year is caused by the sub in my tower speakers. I was running the subs in the towers through the LR speaker signal. Breaking it out as Mark suggested will allow me to FINALLY tame that beast!

It appears that the 40 - 60 hz dip is room induced (both subs have a similar dip).

All 3 subs with EQ on all 3.
Green - 2400 alone
Missing - Towers alone (forgot to measure)
Purple - Combined

Questions:

I tried putting a high pass filter on the tower subs but whenever I did, it would cause a dip in the combined response. I was using the "LR 48db/octave" at 20hz setting in the crossover on the 2x4. Is it that the little bit of output the towers have below 20 makes a difference in combined response? Should I put the filter at 15 or 10hz?

What can I do about the crazyness above 60 hz? Is that helped by adjusting the delay between the subs? If so, what should I try? Would room treatments help in that area (I currently have none)? (my room is carpet over concrete, standard drywall, 10ft ceilings, 17' 5" wide, 16' 8" deep)

I have to admit, turning the tower subs on and off while listening does not give all that much of a difference. You can make out the change but it is not night and day. Turning the 2400 on and off does yield a bigger difference, mostly in frequency range, as expected. What I am gaining is more overhead (you can see the 3db gain in the area the tower subs have output) and probably (untested) more even bass response through the room which is totally worth it to me. Thanks for the suggestion Mark!
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post #9311 of 14521 Old 08-05-2018, 01:23 PM
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Originally Posted by bowlingbeeg View Post
As a reference point I have 2 cap 1400s and after I ran Audyssey I ended up raising the gain by 3 clicks plus I went +6 on the sub trim in the Denon. That works great for my normal listening volume(-15) but if I go above -5 it's a little too much so then I just back off the trim as appropriate. Best advice is to experiment.

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I am not sure but is it not recommended to not go above 0 on sub trim otherwise you might clip some sound. Can anyone please correct me on this. Thanks.
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post #9312 of 14521 Old 08-05-2018, 01:30 PM
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I am not sure but is it not recommended to not go above 0 on sub trim otherwise you might clip some sound. Can anyone please correct me on this. Thanks.


That is correct but I think he means he increase the trim by +6db. I could be wrong. Better right stay well in negative to prevent the sub signal from clipping when listening at higher volume


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Subwoofers: Dual Rythmik FV18s Rev2 with Paper cone, BOSS Platform mini riser, 2 BK LFE
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post #9313 of 14521 Old 08-05-2018, 02:13 PM
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Originally Posted by farsider3000 View Post
It's good to know about the options adjustment by input. But what about: Audio ---> Subwoofer Level Adjust? That seems a faster way to universally adjust the sub level.

So many TV programs and movies are so different I find I need to almost make adjustments per program (if its an action show / movie).
Dont use/enable the Audio-> Subwoofer level adjust function. It doesn't behave as you would expect (brings up sub trim up to 0 even if you had it set to -12 for example). I believe the latest Denon models have removed that function as it's just too confusing and broken.
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post #9314 of 14521 Old 08-05-2018, 03:19 PM
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I still have that subwoofer hum with the cap2400. I re-checked the old svs subwoofer by increasing the gain and noticed it had a slight hum to it too but not as loud the cap2400 (I believe its coz the cap2400 is stronger than the svs). So, I believe its not the Cap but either a ground loop issue or rca cable issue. I have a monoprice 50 feet premium sub cable and I tried switching to a mediabridge 25 feet sub cable but the hum didn't go away. Next was changing the power outlet..no help. Then I connected a long extension cord to the same outlet as the amp is connected to, and the hum decreased although not completely gone. So a this point I have 2 options: Try another rca cable like blue jeans (mentioned by Ereed in his previous post) or go with a ground loop isolator such as this one:

https://www.amazon.com/gp/product/B0...TPY3ZC5Y&psc=1

Both are expensive options but I dont have a choice at this time. Will a ground loop isolator also clip off some sounds for the lfe channel when connected between the rca cable? Any recommendations or suggestions please?
Thanks
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post #9315 of 14521 Old 08-05-2018, 09:02 PM
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@mir3acles before you buy anything I have encountered similar problems with AVRs with two-prong power cords connecting the subs with 3-prong power cords (earth ground).

If your AVR has a phono signal ground or any metal chassis screw you can run a wire from the AVR chassis to a ground lug on your power center or even the center screw on your outlet.

For a ground loop isolator (1:1 transformer) they start around $25 but some roll off around 20Hz. I do think it is worth the $50 for Ebtech or BJC.

Edit: The best solution I know of are the Audioquest subwoofer cables with connectors to tie the AVR chassis to the sub plate amp chassis. However, these cables are way overpriced! I have a few I've collected on closeout and they work wonderfully (Sub-A, Sub-X, Black Lab). You can always run your own ground cable alongside your coax.

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post #9316 of 14521 Old 08-06-2018, 07:30 AM
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Originally Posted by schwaggs View Post
I connected everything up last night and took some measurements. I ran separate outputs from the 2X4 into each sub (2400, Left, Right).

The tower speakers are along the screen wall and flank my 120" screen which is centered on the screen wall. Each speaker is about 38 inches from each side wall. I have ZERO flexibility in this setup, there are doorways between the speakers and side walls. The 2400 is against the front wall in the exact center of the wall. MLP is 2 seats centered in the room (each MLP is off center by the width of a chair, if that makes sense).

I turned on 1/48 smoothing to make the above 80 response look less confusing. I can post non-smoothed graph if preferred. It really has little to no effect on the lower parts of the graph.

Subs without EQ
Blue - Towers
Yellow - 2400
Purple - combined

One HUGE takeaways from this for me: The 32hz spike I have been fighting for over a year is caused by the sub in my tower speakers. I was running the subs in the towers through the LR speaker signal. Breaking it out as Mark suggested will allow me to FINALLY tame that beast!

It appears that the 40 - 60 hz dip is room induced (both subs have a similar dip).

All 3 subs with EQ on all 3.
Green - 2400 alone
Missing - Towers alone (forgot to measure)
Purple - Combined

Questions:

I tried putting a high pass filter on the tower subs but whenever I did, it would cause a dip in the combined response. I was using the "LR 48db/octave" at 20hz setting in the crossover on the 2x4. Is it that the little bit of output the towers have below 20 makes a difference in combined response? Should I put the filter at 15 or 10hz?

What can I do about the crazyness above 60 hz? Is that helped by adjusting the delay between the subs? If so, what should I try? Would room treatments help in that area (I currently have none)? (my room is carpet over concrete, standard drywall, 10ft ceilings, 17' 5" wide, 16' 8" deep)

I have to admit, turning the tower subs on and off while listening does not give all that much of a difference. You can make out the change but it is not night and day. Turning the 2400 on and off does yield a bigger difference, mostly in frequency range, as expected. What I am gaining is more overhead (you can see the 3db gain in the area the tower subs have output) and probably (untested) more even bass response through the room which is totally worth it to me. Thanks for the suggestion Mark!
Very good job on the homework, and very good info. There is a good deal more you can do with the results, and it is very useful to know about the ~35Hz peak.



A few things to understand before you start tinkering. When the 2 curves are at the same level, the two curves can combine to up to +6dB vs the individual. This is where the big potential gain lies in the 40-60Hz range. The key will be figuring out the correct delay and high pass filter settings. Right now you are not getting maximum summation quite where you need it as you can see just above 50Hz where the curves cross, the summed response is almost the same. This means the signals are about 90 deg out from each other. If you left things as is and added 4-5ms of delay to the Polks I expect you would see a dramatic change that interaction, but the delay needed will change once you add some EQ and a high pass.

The complicating factor is that when you add a high pass filter, it also shifts the phase/delay around vs frequency. The steeper the filter, the more delay. There's no need for a 48dB/oct filter on the Polk tower subs, so I would first add at PEQ filter around 35Hz only to the Polk's. Adjust this without the high pass in place, and use a gain of -5 to -8dB to bring the peak toward the 80dB line on the graph you posted. Adjust the width/Q of the filter to not impact too much above 40Hz, but still wide enough so it still looks like a smooth mound (a notch in the middle of the peak means it's too narrow or too deep a cut). Once that peak is tamed some I would then add a 24dB/oct set around 35-40Hz, where the roll off will help further pull down the peak in the Polks. You really only care about the contribution of the Polk's above 40Hz, and this will help make sure they don't work so hard keeping up with the system. Once you have the PEQ and high pass set, now redo the overlay you posted of the 2400, the Polk's, and the combined response.

Once you have the responses to combine, I believe the multi-subwoofer optimizer would allow you to load in the measurements and play with delay and level settings in the computer if you didn't want to do it with the real responses. You can calculate the approximate amount of delay needed to shift a frequency by 1/4 or 1/2 period. If the 2 curves add to the same value, they are 1/4 wavelength, or 90 deg off. If they cause a deep cancellation, they are 1/2 wavelength or 180 deg off. You can calculate in milliseconds the value for either by taking 1/(4*F), or 1/(2*F) and multiplying by 1000. This gives you a starting point to make a big change, and then you can make +/- adjustments from that starting point.

Referencing the curves you posted above, I expect the right settings should allow you to reduce the dip in the 50Hz range such that it doesn't go below 75dB. This will allow you to reduce the boost you have on the 2400 in the 40-60Hz range, and will likely make things a little more even through the room.

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post #9317 of 14521 Old 08-06-2018, 06:32 PM
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Very good job on the homework, and very good info. There is a good deal more you can do with the results, and it is very useful to know about the ~35Hz peak.



A few things to understand before you start tinkering. When the 2 curves are at the same level, the two curves can combine to up to +6dB vs the individual. This is where the big potential gain lies in the 40-60Hz range. The key will be figuring out the correct delay and high pass filter settings. Right now you are not getting maximum summation quite where you need it as you can see just above 50Hz where the curves cross, the summed response is almost the same. This means the signals are about 90 deg out from each other. If you left things as is and added 4-5ms of delay to the Polks I expect you would see a dramatic change that interaction, but the delay needed will change once you add some EQ and a high pass.

The complicating factor is that when you add a high pass filter, it also shifts the phase/delay around vs frequency. The steeper the filter, the more delay. There's no need for a 48dB/oct filter on the Polk tower subs, so I would first add at PEQ filter around 35Hz only to the Polk's. Adjust this without the high pass in place, and use a gain of -5 to -8dB to bring the peak toward the 80dB line on the graph you posted. Adjust the width/Q of the filter to not impact too much above 40Hz, but still wide enough so it still looks like a smooth mound (a notch in the middle of the peak means it's too narrow or too deep a cut). Once that peak is tamed some I would then add a 24dB/oct set around 35-40Hz, where the roll off will help further pull down the peak in the Polks. You really only care about the contribution of the Polk's above 40Hz, and this will help make sure they don't work so hard keeping up with the system. Once you have the PEQ and high pass set, now redo the overlay you posted of the 2400, the Polk's, and the combined response.

Once you have the responses to combine, I believe the multi-subwoofer optimizer would allow you to load in the measurements and play with delay and level settings in the computer if you didn't want to do it with the real responses. You can calculate the approximate amount of delay needed to shift a frequency by 1/4 or 1/2 period. If the 2 curves add to the same value, they are 1/4 wavelength, or 90 deg off. If they cause a deep cancellation, they are 1/2 wavelength or 180 deg off. You can calculate in milliseconds the value for either by taking 1/(4*F), or 1/(2*F) and multiplying by 1000. This gives you a starting point to make a big change, and then you can make +/- adjustments from that starting point.

Referencing the curves you posted above, I expect the right settings should allow you to reduce the dip in the 50Hz range such that it doesn't go below 75dB. This will allow you to reduce the boost you have on the 2400 in the 40-60Hz range, and will likely make things a little more even through the room.

Wow Mark, thank you for all the expert advise, detailed information and help! Very nice of you!


I have a long USB cable so I can adjust the 2X4, measure, repeat from the comfort of my chair. I will spend some time tweaking tomorrow and/or the next day.


Thanks for the lead on the multi-sub optimizer software. Yet another fun tool to learn!



Thanks for the insight on the response curves crossing. What you explained makes perfect sense.



My AVR set the 2400 distance as 22 feet even though the actual distance is more like 10 feet. I suspect the 2X4 adds a little delay and the AVR may be compensating. All the testing so far has been done with the 22 foot distance MCCAC calculated. What AVR distance should I use while optimizing these subs? Keep what the AVR calculated? Override the AVR and set it to the physical distance? Measure various distances and start with the smoothest one? I know from prior testing that other distances yield smoother, un-equalized response curves but not sure if changing it is a good idea as it relates to blending with the main speakers.
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post #9318 of 14521 Old 08-07-2018, 07:51 AM
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Wow Mark, thank you for all the expert advise, detailed information and help! Very nice of you!


I have a long USB cable so I can adjust the 2X4, measure, repeat from the comfort of my chair. I will spend some time tweaking tomorrow and/or the next day.


Thanks for the lead on the multi-sub optimizer software. Yet another fun tool to learn!



Thanks for the insight on the response curves crossing. What you explained makes perfect sense.



My AVR set the 2400 distance as 22 feet even though the actual distance is more like 10 feet. I suspect the 2X4 adds a little delay and the AVR may be compensating. All the testing so far has been done with the 22 foot distance MCCAC calculated. What AVR distance should I use while optimizing these subs? Keep what the AVR calculated? Override the AVR and set it to the physical distance? Measure various distances and start with the smoothest one? I know from prior testing that other distances yield smoother, un-equalized response curves but not sure if changing it is a good idea as it relates to blending with the main speakers.
Just make sure to keep in mind (and it's a good thing) that when you add distance to your sub in the AVR, what it's actually doing is adding delay to the rest of the system to bring it in line with the delay the minidsp or other DSP is inherently causing. If you end up adding more delay in the mini to the subs, you may need to increase the distance even more in the AVR after the fact.

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post #9319 of 14521 Old 08-07-2018, 09:49 AM
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@ mir3acles

I read over your last few posts and it doesn't seem that you have figured out the source of the hum. Before you start ordering possible remedies online, you need to do that. Amazon prime membership is handy now...

First thing I can think of is, is the subwoofer plugged into a circuit that has a dimmer switch on it? If you have the sub in the family room, this might happen. Dimmer switches cause hum. If so, you should move the sub to another location where the receptacle is in a different circuit. If not, get this:

https://www.amazon.com/Transformer-E...on+transformer

Then what happens if you disconnect the coaxial cable (RG-6U) for the cable box? Does the hum go away? This is usually the No. 1 culprit. If the hum goes away, then you need something like this:

https://www.amazon.com/Isolation-Tra...+loop+isolator

Many people have had great success with the following, but it costs 3 times as much as above. You should try the cheaper one first.

https://www.amazon.com/Viewsonics-VS...+loop+isolator

If the hum is still there after you disconnect the coaxial cable, then you can try a different (new) subwoofer cable.

Then you can try the following:

https://www.amazon.com/Transformer-E...on+transformer

Good luck!
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post #9320 of 14521 Old 08-07-2018, 08:59 PM
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I still have that subwoofer hum with the cap2400. I re-checked the old svs subwoofer by increasing the gain and noticed it had a slight hum to it too but not as loud the cap2400 (I believe its coz the cap2400 is stronger than the svs). So, I believe its not the Cap but either a ground loop issue or rca cable issue. I have a monoprice 50 feet premium sub cable and I tried switching to a mediabridge 25 feet sub cable but the hum didn't go away. Next was changing the power outlet..no help. Then I connected a long extension cord to the same outlet as the amp is connected to, and the hum decreased although not completely gone. So a this point I have 2 options: Try another rca cable like blue jeans (mentioned by Ereed in his previous post) or go with a ground loop isolator such as this one:

https://www.amazon.com/gp/product/B0...TPY3ZC5Y&psc=1

Both are expensive options but I dont have a choice at this time. Will a ground loop isolator also clip off some sounds for the lfe channel when connected between the rca cable? Any recommendations or suggestions please?
Thanks
This may sound like a no-brainer, but did you check the switch on the amp plate to make sure the toggle is set to RCA and not XLR? When I first got my Cap 1400 it was also humming, and I had never even thought about the switch. I eventually figured it out, flipped the switch, and the hum disappeared.

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post #9321 of 14521 Old 08-08-2018, 10:44 AM
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That is correct but I think he means he increase the trim by +6db. I could be wrong. Better right stay well in negative to prevent the sub signal from clipping when listening at higher volume


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Yes, that is what I meant. Still in the negative range. -9 to -3

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post #9322 of 14521 Old 08-09-2018, 01:03 PM
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Just wanted to chime in..

A posted a thread a few weeks ago looking for suggestions on a new sub and pulled the trigger on TWO Cap 2400s!! Really looking forward to joining the JTR family and share my impressions

I'm coming from Dual PB12NSDs and have no idea what I'll be in store for but I'm excited to find out!

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post #9323 of 14521 Old 08-09-2018, 10:43 PM
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This may sound like a no-brainer, but did you check the switch on the amp plate to make sure the toggle is set to RCA and not XLR? When I first got my Cap 1400 it was also humming, and I had never even thought about the switch. I eventually figured it out, flipped the switch, and the hum disappeared.
Where is the toggle switch located? Cannot find it on the back. Thanks.
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post #9324 of 14521 Old 08-09-2018, 11:55 PM
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Originally Posted by mir3acles View Post
Where is the toggle switch located? Cannot find it on the back. Thanks.
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Subwoofer: JTR Captivator 4000ULF.
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post #9325 of 14521 Old 08-10-2018, 12:27 AM
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Where is the toggle switch located? Cannot find it on the back. Thanks.
It was reported previously that the newer amps do not have the switch.
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The XLR/RCA switch was really just a 6dB pad. The RCA & XLR inputs have always both been active on the Speakerpower amps AFAIK. Some folks probably have them flipped and don't even know. Guilty!
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post #9326 of 14521 Old 08-10-2018, 05:45 AM
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Originally Posted by srw1000 View Post
This may sound like a no-brainer, but did you check the switch on the amp plate to make sure the toggle is set to RCA and not XLR? When I first got my Cap 1400 it was also humming, and I had never even thought about the switch. I eventually figured it out, flipped the switch, and the hum disappeared.
Weird, I have two cap 1400's and after I read your post I switch both mine over to XLR and nothing, no hum, no bass. Switched them back to RCA and they were back to normal. I wonder if something else is going on with the subs you guys have. Sounds like time for process of elemination. Try a different receiver, then swap out cables etc.
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post #9327 of 14521 Old 08-10-2018, 08:02 AM
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Originally Posted by sthompson View Post
I'm looking to add two ULF4000's to my home theater. A few questions.

1) Is there anything in this price range that beats the ULF4000 in terms of output? I currently have a set of Seaton Submersives and want to add some additional mid-bass slam and lower output.
2) Is there anyone in the Omaha/Lincoln NE region that would be willing to demo their ULF4000?
3) Are there any upcoming audio shows where the ULF4000 will be at?

Thanks
I will be delivering two Captivator 4000ULF's to sthompson in several weeks. Hopefully they will satiate his bass desires.

I'm also doing a little bit of a JTR speaker/sub shuffle this weekend. I'm picking up an S2 and a pair of Noesis 210RT's for my new house. I'm delivering my 215RT's to a new customer since I'm going with 215RM's in my new theater. I may be picking up some 212HTR's for another customer. Finally, I'm calibrating a 7.1.4 room with Noesis 212HTs (original 3-way), dual Orbit Shifter LFU's, and (8) Single 8's. It will be the second dual Orbit Shifter LFU room I've heard in the past two weeks. I also setup a dual Captivator S1 room last weekend.

I demoed several systems for a customer a few weeks ago: a Danley DTS-10 and tactile transducers, Quad sealed Dayton UM18-22 with tactile transducers, dual ported Mach 5 Audio UXL-18 subs, and dual Orbit Shifter LFU's. After hearing the Orbit Shifter LFU's (which he will also have in his new theater), he decided tactile transducers aren't necessary.
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post #9328 of 14521 Old 08-10-2018, 08:54 AM
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Originally Posted by mir3acles View Post
Where is the toggle switch located? Cannot find it on the back. Thanks.
Yeah, my new 2400's do not have a toggle switch for RCA/XLR.

Todd
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post #9329 of 14521 Old 08-10-2018, 07:51 PM
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Weird, I have two cap 1400's and after I read your post I switch both mine over to XLR and nothing, no hum, no bass. Switched them back to RCA and they were back to normal. I wonder if something else is going on with the subs you guys have. Sounds like time for process of elemination. Try a different receiver, then swap out cables etc.
That is odd. My Cap 1400s were the original version, one from the special introductory offer. Maybe that has something to do with it? Hasn't been a problem since I flipped the switch.

I didn't know that the toggle was eliminated, so I guess that eliminates it as a possible cause for mir3acles.

Scott

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post #9330 of 14521 Old 08-10-2018, 08:08 PM - Thread Starter
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Originally Posted by mir3acles View Post
I still have that subwoofer hum with the cap2400. I re-checked the old svs subwoofer by increasing the gain and noticed it had a slight hum to it too but not as loud the cap2400 (I believe its coz the cap2400 is stronger than the svs). So, I believe its not the Cap but either a ground loop issue or rca cable issue. I have a monoprice 50 feet premium sub cable and I tried switching to a mediabridge 25 feet sub cable but the hum didn't go away. Next was changing the power outlet..no help. Then I connected a long extension cord to the same outlet as the amp is connected to, and the hum decreased although not completely gone. So a this point I have 2 options: Try another rca cable like blue jeans (mentioned by Ereed in his previous post) or go with a ground loop isolator such as this one:

https://www.amazon.com/gp/product/B0...TPY3ZC5Y&psc=1

Both are expensive options but I dont have a choice at this time. Will a ground loop isolator also clip off some sounds for the lfe channel when connected between the rca cable? Any recommendations or suggestions please?
Thanks

Besides methods that other people (Marc/chucky) have suggested, if you haven't done so may I also suggest Home Depot cheater plugs for both the subwoofer and any amp/preamp/componets with 3 prong plug? Cheap and quick trial.

Regards, Can
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