Author Topic: Unable to hear 30Hz on sub  (Read 766 times)

Offline naks

Unable to hear 30Hz on sub
« on: December 02, 2019, 08:55:48 AM »
Hi everyone,

I recently bought an SVS-PB-1000 sub, and enjoying the nice bass that it puts out.

Having read the specs that it goes down to 19Hz, I thought I'd see if I can hear at that frequency.

I queued up a few Youtube clips with test tones, and sure enough, there was still a barely-audible sound at 19Hz. I could be mistaken, but I'm sure I could still hear/feel something at 18Hz as well.

However, in almost every test tone that I played, at 30Hz the sub seems to 'disappear': I can't hear anything at that frequency, and neither can my wife.

this is the clip that I played a few times: https://youtu.be/2tr9-PzJl_c

Firstly, are these clips reliable enough?

Seconly, is the 'dip' at 30Hz normal, or is something wrong with the sub?  :???:

Thanks
LG OLED55C7, Oppo UDP-203, Cambridge Audio CXR200, PSB Imagine T2 towers (bi-amped), PSB Image C5 centre, Monitor Audio Bronze FX surrounds (bipole), SVS PB-1000 sub

Offline Jason Willemse

Re: Unable to hear 30Hz on sub
« Reply #1 on: December 02, 2019, 09:08:55 AM »
Welcome to the world of “modes”. Every room has them... unique to each.

Place that sub in a different room and you will find the loss will be at a different frequency.

Equally, you will find a certain frequency being naturally amplified in your room, and applied each time that frequency is doubled or halved.


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Offline naks

Re: Unable to hear 30Hz on sub
« Reply #2 on: December 02, 2019, 09:28:33 AM »
Ah, interesting, thanks.

Does this subwoofer setup procedure look ok to you:

Quote
Lets start with the subwoofer:
  • Set the Volume to 2 pm.
  • Set the Low Pass Filter to LFE (all the way to the right)
  • Set the Phase to 0 (all the way to the left)

On the Receiver please go into manual settings and make the following setting changes as needed:
  • Set all speakers to small.
  • Set the level of your subwoofer to -5 dB
  • Set the crossover for all your speakers to 80 Hz
  • Let the LPF to LFE and LFE to 120 Hz (in the bass menu)
  • In the audio menu, locate Auddyssey and make sure Dynamic EQ is on with a Reference level of 0 and Dynamic Volume is off.
LG OLED55C7, Oppo UDP-203, Cambridge Audio CXR200, PSB Imagine T2 towers (bi-amped), PSB Image C5 centre, Monitor Audio Bronze FX surrounds (bipole), SVS PB-1000 sub

Online windshear

Re: Unable to hear 30Hz on sub
« Reply #3 on: December 02, 2019, 09:32:48 AM »
With regard to the room modes, just move to a different location in the room and that will take you out of the null if it is one. Literally 1 or 2 m will shift the null in frequency so the 30 Hz should become audible. If not then something else is at play. How have you set the sub up in terms of its back panel settings?

Offline KenMasters

Re: Unable to hear 30Hz on sub
« Reply #4 on: December 02, 2019, 09:36:47 AM »
Ah, interesting, thanks.

Does this subwoofer setup procedure look ok to you:

2pm seems a bit high, do you have a means of testing output - does your receiver have an auto-setup feature or do you use REW?

If your AVR doesn't have a room EQ feature, then you need to play around with the phase, leaving it at 0 is for systems with room EQ.

Saying you should set your AVR's sub level to -5 is arbitrary, you should set the gain on the sub to as close to correct as you can, the AVR's setup routine (or yourself) can adjust thereafter if necessary.

80Hz is a good rough guide for the crossover, but if you are able to measure your system's performance, you might find something higher or lower works better.

I don't like to use Dynamic EQ personally, I find with my setup in my room, it swings too dramatically.

Offline chrisc

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Re: Unable to hear 30Hz on sub
« Reply #5 on: December 02, 2019, 10:23:48 AM »
I got a sub to reproduce even lower frequencies than the spec by having it fire into the corner of the room
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Offline naks

Re: Unable to hear 30Hz on sub
« Reply #6 on: December 02, 2019, 10:51:17 AM »
2pm seems a bit high, do you have a means of testing output - does your receiver have an auto-setup feature or do you use REW?
If your AVR doesn't have a room EQ feature, then you need to play around with the phase, leaving it at 0 is for systems with room EQ.
Saying you should set your AVR's sub level to -5 is arbitrary, you should set the gain on the sub to as close to correct as you can, the AVR's setup routine (or yourself) can adjust thereafter if necessary.
80Hz is a good rough guide for the crossover, but if you are able to measure your system's performance, you might find something higher or lower works better.
I don't like to use Dynamic EQ personally, I find with my setup in my room, it swings too dramatically.


Well, the Cambridge Audio has an auto-setup, but no room correction, and I've found the auto-setup to be quite useless.

At the moment, I have the AVR subwoofer output to +15dB and the sub's volume to about 8 o'clock - but that is to mainly get the sub's active standby to fire up.

I will try the setup procedure from SVS and see if it makes a difference.

thanks
LG OLED55C7, Oppo UDP-203, Cambridge Audio CXR200, PSB Imagine T2 towers (bi-amped), PSB Image C5 centre, Monitor Audio Bronze FX surrounds (bipole), SVS PB-1000 sub

Offline DACMan1

Re: Unable to hear 30Hz on sub
« Reply #7 on: December 02, 2019, 11:28:47 AM »
I got a sub to reproduce even lower frequencies than the spec by having it fire into the corner of the room

Well, the frequency range for a sub is usually the -6dB point - so there is still plenty of energy there. After that it drops off at a slope determined by the box design, 24dB/octave for vented (more accurately after the -3dB point).

Youtube is probably also not the best source for test tracks.

Offline Carnajo

Re: Unable to hear 30Hz on sub
« Reply #8 on: December 02, 2019, 12:02:34 PM »
Have you tried with a tone generator app or something other than Youtube? It's always possible that youtube is doing something funny, or the compression kills something, or well, something? I know for example youtube cuts frequency above 16khz.

Offline naks

Re: Unable to hear 30Hz on sub
« Reply #9 on: December 02, 2019, 12:09:22 PM »
Have you tried with a tone generator app or something other than Youtube? It's always possible that youtube is doing something funny, or the compression kills something, or well, something? I know for example youtube cuts frequency above 16khz.

no, I haven't, thanks for the suggestion.

Ok, so I tried the SVS method for setting up the sub, and it was pretty spot on. The only tweak I did was to turn down the sub's volume from 2 o'c'ock to just short of 1 because the bass was bit too 'boomy' for my taste.
LG OLED55C7, Oppo UDP-203, Cambridge Audio CXR200, PSB Imagine T2 towers (bi-amped), PSB Image C5 centre, Monitor Audio Bronze FX surrounds (bipole), SVS PB-1000 sub

Offline Katji

Re: Unable to hear 30Hz on sub
« Reply #10 on: December 02, 2019, 12:54:46 PM »
16 KHz is where 128 Kbps mp3 compression cuts off, how I check downloaded 320 Kbps to verify...but I'm sure it does something with the bass too.