Curious problem about subwoofer placement

[Miguelón]

Hello!

I recently purchased my first sub, Kali WS 6.2, very happy with the integration with my speakers but I have an original personal issue.

I suffer from a visual impairment that led to automatic use of echo-location since I was a child: as a result it seems I use time delay reflections from the floor to help balance.

I don’t know exactly how it works, but since I have my sub I inevitably tilt my head to the floor, I ended by switching it off.

My solution can be to place the sub at a height, over a floor stand, to reduce strong floor reflections or keep celling / floor reflections balanced.

Any technical reason to place always the subs on the floor? Otherwise It’s performances will be importantly reduced?

If not, I will purchase a 1 m floor stand or a variable height one, to try different heights.

Thanks!

 

[alex-z]

There is nothing wrong with elevating a subwoofer, it is just inconvenient. Performance may improve due to exciting room modes more evenly.

Being able to hear the location of a subwoofer is usually due to the crossover slopes being too shallow or the frequency being set too high.

The W.S 6.2 appears to only have an 80Hz option and the slope is not listed. If your speakers can play low enough try a more aggressive external crossover, such as 60Hz with a 24dB slope.

 

[Miguelón]

There is nothing wrong with elevating a subwoofer, it is just inconvenient. Performance may improve due to exciting room modes more evenly.

Being able to hear the location of a subwoofer is usually due to the crossover slopes being too shallow or the frequency being set too high.

The W.S 6.2 appears to only have an 80Hz option and the slope is not listed. If your speakers can play low enough try a more aggressive external crossover, such as 60Hz with a 24dB slope.

I use the digital crossover of my WiiM at 90 Hz. It doesn’t allow to change the slope, but I can set the cutoff as low as I want.

Thanks for the advice, my Genelecs G Three behave reasonably good at 60 Hz, at the SPL I use to play: no problem to change.

In fact I chose the Kali because my intention was to reinforce the 40-50 Hz range in jazz and some rock music, not so interested in very low ends.

PS: I’ve just tried now, thanks a lot! The floor reflections seems to be way lees perturbing, if not at all. The monitors doesn’t sound as airy as at 85-90 Hz cutoff, but is a minor problem.

Getting to 100 Hz as an experiment, it becomes horrible to me !

 

[ZolaIII]

Try to lower the inherent vibrations from the floor and place sub to the middle of speakers (it's much more important horizontal [separation] then vertical). To the back wall so it picks up back to front but with minimal timing difference. The low end of spectrum under 45 Hz is a big unified standing wave which sums perfectly (+6 dB) from 75 that drops to +3 dB and in between it's a slope in that regard. Lower you go you exide woofer more and it dosent have time to decay before next amplitude comes up. Up to 10" sealed it's not a problem to let it lose, over that you aim to have it under control by cutting it off so it stays very good or good (7~10 ms frame). Best practice is just to after where impedance and phase meet after driver FS but you can go a bit under it also depending what you prioritise there. Then there is a room decay time's to indexes to frequency ranges (RT) and what's considered good and very good to index how it's level is to direct sound and ways to improve it. Ambient noise also plays a role (of acceptable program SPL) but I believe you are also very sensitive to it and live in rather quiet environment (mid to uper 30's range). Timings are the key thing no matter how you look at it.
You aim at mid to low 30's Hz output and as linear as you can when you go to pick to buy a sub and remember it's to enclosure and used measuring methodology.
That what you bought is 2x opposite firing 6.5" drivers as a good single 8" one and probably very stiff and inefficient (that's why they tried to compensate with amp) doing 0 dB at about 70 Hz (65 combined) hardly will ever get you even close to desired by any means even with clever use of room reinforcement (which again has its upside down regarding room decay).
If its desktop uper desk plate is a problem which you won't solve and explains the feeling you are getting. Scale it in space and it will get better, when you get chance try with 2.2 out of desk bounderis (behind and wider than desk is to each side and belonging main speaker it's own sub crossed high at 120 Hz [let them sum on their own] with at least two good compression 10" ones to get to 30, 25 Hz with room 0 dB).

 

[Hear Here]

I'd agree that the XO should be set as low as you can without creating a "gap" between what the main and sub speakers deliver. Also remember you can place your sub well away from your main speakers as very low frequencies disguise their source location. If floor reflections are a problem, consider positioning the sub behind a sofa or on a carpet or rug somewhere.

 

[Miguelón]

I'd agree that the XO should be set as low as you can without creating a "gap" between what the main and sub speakers deliver. Also remember you can place your sub well away from your main speakers as very low frequencies disguise their source location. If floor reflections are a problem, consider positioning the sub behind a sofa or on a carpet or rug somewhere.

I realized that, when placing my exploration table after closing my clinic over the sub, the issue is less pronounced.

I can do that, the carpet is not a good solution because I use the floor for exercises: maybe I can install a mosaic rubber floor that probably has less reflective index than my wood floor.

 

[Miguelón]

Try to lower the inherent vibrations from the floor and place sub to the middle of speakers (it's much more important horizontal [separation] then vertical). To the back wall so it picks up back to front but with minimal timing difference. The low end of spectrum under 45 Hz is a big unified standing wave which sums perfectly (+6 dB) from 75 that drops to +3 dB and in between it's a slope in that regard. Lower you go you exide woofer more and it dosent have time to decay before next amplitude comes up. Up to 10" sealed it's not a problem to let it lose, over that you aim to have it under control by cutting it off so it stays very good or good (7~10 ms frame). Best practice is just to after where impedance and phase meet after driver FS but you can go a bit under it also depending what you prioritise there. Then there is a room decay time's to indexes to frequency ranges (RT) and what's considered good and very good to index how it's level is to direct sound and ways to improve it. Ambient noise also plays a role (of acceptable program SPL) but I believe you are also very sensitive to it and live in rather quiet environment (mid to uper 30's range). Timings are the key thing no matter how you look at it.
You aim at mid to low 30's Hz output and as linear as you can when you go to pick to buy a sub and remember it's to enclosure and used measuring methodology.
That what you bought is 2x opposite firing 6.5" drivers as a good single 8" one and probably very stiff and inefficient (that's why they tried to compensate with amp) doing 0 dB at about 70 Hz (65 combined) hardly will ever get you even close to desired by any means even with clever use of room reinforcement (which again has its upside down regarding room decay).
If its desktop uper desk plate is a problem which you won't solve and explains the feeling you are getting. Scale it in space and it will get better, when you get chance try with 2.2 out of desk bounderis (behind and wider than desk is to each side and belonging main speaker it's own sub crossed high at 120 Hz [let them sum on their own] with at least two good compression 10" ones to get to 30, 25 Hz with room 0 dB).

I will take few of the ideas, others I don’t understand well: I will think about them later.

Thanks so much!

 

[Mort]

I realized that, when placing my exploration table after closing my clinic over the sub, the issue is less pronounced.

I can do that, the carpet is not a good solution because I use the floor for exercises: maybe I can install a mosaic rubber floor that probably has less reflective index than my wood floor.

How are you getting reflections from a sub? Should be omnidirectional, no?

 

[Miguelón]

How are you getting reflections from a sub? Should be omnidirectional, no?

I don’t know if are reflections. I feel them from the floor, or at least I tilt my head towards it.

That’s logical, in that frequency they act more as standing waves than irradiating pattern.

But this not exclude reflections, I think… I don’t know.

As far as I know, the wall, floor and celling will restitute sound energy by reflection, and the front wave should be at some angle. So why not calling them reflections?

Light from a bulb travels also omnidirectional, and we call reflections when it bound from a reflecting surface…

 

[dominikz]

Hello!

I recently purchased my first sub, Kali WS 6.2, very happy with the integration with my speakers but I have an original personal issue.

I suffer from a visual impairment that led to automatic use of echo-location since I was a child: as a result it seems I use time delay reflections from the floor to help balance.

I don’t know exactly how it works, but since I have my sub I inevitably tilt my head to the floor, I ended by switching it off.

My solution can be to place the sub at a height, over a floor stand, to reduce strong floor reflections or keep celling / floor reflections balanced.

Any technical reason to place always the subs on the floor? Otherwise It’s performances will be importantly reduced?

If not, I will purchase a 1 m floor stand or a variable height one, to try different heights.

Thanks!

Just note that if you elevate the sub you will change the floor/ceiling SBIR null frequencies.

With a 2.6m ceiling height and the sub on the floor, the floor SBIR null will be out of the subs operating range, while the ceiling null will be around 35Hz.

If you elevate the sub so that the center of the sub's driver is at 1.3m (center point between floor and ceiling) both nulls would overlap at 66Hz - making the null more severe.

Perhaps this online calculator may be helpful.

 

[Miguelón]

Just note that if you elevate the sub you will change the floor/ceiling SBIR null frequencies.

With a 2.6m ceiling height and the sub on the floor, the floor SBIR null will be out of the subs operating range, while the ceiling null will be around 35Hz.

If you elevate the sub so that the center of the sub's driver is at 1.3m (center point between floor and ceiling) both nulls would overlap at 66Hz - making the null more severe.

Perhaps this online calculator may be helpful.

Thanks!

By the other advices I understood that elevating the sub won’t improve the problem, this confirms the same and add poorer room response.

Actually I replaced the subwoofer close to a coin, put some stuff around (foam gym mats, foam cushions…), resynchronized WiiM with sub by placing the WiiM in my listening position, and down the crossover.

All was very useful, thanks for your advice!

PS: I understood that low freq. perturbe my balance and cause some fatigue, so I cutoff <80 Hz frequencies from time to time, specially when I let the ambience music during work. I reserve the sub and low frequencies to dedicated listening

 

[dominikz]

Thanks!

By the other advices I understood that elevating the sub won’t improve the problem, this confirms the same and add poorer room response.

Actually I replaced the subwoofer close to a coin, put some stuff around (foam gym mats, foam cushions…), resynchronized WiiM with sub by placing the WiiM in my listening position, and down the crossover.

All was very useful, thanks for your advice!

PS: I understood that low freq. perturbe my balance and cause some fatigue, so I cutoff <80 Hz frequencies from time to time, specially when I let the ambience music during work. I reserve the sub and low frequencies to dedicated listening

If you haven't, my advice is to try and run RoomFit to knock down any room resonances - perhaps that would help. I'd suggest to limit the RoomFit correction range up to 300Hz, use variable smoothing, and enable non-boost mode.
Do note that RoomFit works best if placement is optimized - so in case it helps, I've previously written some suggestions on subwoofer integration/placement on the WiiM forum (see link). Those were written for an SVS sub with on-board DSP (which adds some additional processing latency and so impacts delay settings).

Good luck!

 

[Miguelón]

I'd suggest to limit the RoomFit correction range up to 300Hz, use variable smoothing, and enable non-boost mode.

I used RoomFit many time, nice tool. Bit I found too much correction, usually I take half the SPL of filters and try to don’t go over 5 Q factor.

Never used “Non-boost mode”, I’ll try it.

I red your guide, nice work!

My Kali WS 6.2 has a tremendous amount of SGN in the LFE mode, a replacement unit didn’t solve the issue. Is so high that we can hear it at the opposite side of the room.

We’re thinking about selling it, and go to a WiiM Sub Pro.

The advantage is that I can move it without cables, and should integrate well with my WiiM Ultra.

Other option will be SVS 3000 micro, with also dedicated app to phase and tune.

Any suggestion between those 2 subwoofers?

The Kali must go, the noise is unacceptable and only disappears when using the 80 Hz internal crossover.

 

[dominikz]

I used RoomFit many time, nice tool. Bit I found too much correction, usually I take half the SPL of filters and try to don’t go over 5 Q factor.

Never used “Non-boost mode”, I’ll try it.

IMHO the introduction of the Non-Boost Mode, Moving Mic Measurement and variable smoothing significantly improved RoomFit.

We’re thinking about selling it, and go to a WiiM Sub Pro.

The advantage is that I can move it without cables, and should integrate well with my WiiM Ultra.

Other option will be SVS 3000 micro, with also dedicated app to phase and tune.

Any suggestion between those 2 subwoofers?

I don't have personal experience with either of those subs, sorry! I use a SVS SB-1000 Classic in one of my systems and I'm really happy with that one.
That being said, I'd personally expect the SVS 3000 Micro to do better than the WiiM Sub Pro - but it's hard to be certain since we have no CEA-2010 data for the WiiM Sub Pro.

 

[Neuro]

Hello!

I recently purchased my first sub, Kali WS 6.2, very happy with the integration with my speakers but I have an original personal issue.

I suffer from a visual impairment that led to automatic use of echo-location since I was a child: as a result it seems I use time delay reflections from the floor to help balance.

I don’t know exactly how it works, but since I have my sub I inevitably tilt my head to the floor, I ended by switching it off.

My solution can be to place the sub at a height, over a floor stand, to reduce strong floor reflections or keep celling / floor reflections balanced.

Any technical reason to place always the subs on the floor? Otherwise It’s performances will be importantly reduced?

If not, I will purchase a 1 m floor stand or a variable height one, to try different heights.

Thanks!

I'm a little confused. Echolocation actively uses higher frequencies that shouldn't be masked by a subwoofer. Maybe you're using lower frequencies than normal when navigating that can be masked by the subwoofer. Or maybe the subwoofer is broken and producing too high frequencies. A normally functioning subwoofer shouldn't mask echolocation. Or have I misunderstood your problem.

JM

 

[ZolaIII]

I used RoomFit many time, nice tool. Bit I found too much correction, usually I take half the SPL of filters and try to don’t go over 5 Q factor.

Never used “Non-boost mode”, I’ll try it.

I red your guide, nice work!

My Kali WS 6.2 has a tremendous amount of SGN in the LFE mode, a replacement unit didn’t solve the issue. Is so high that we can hear it at the opposite side of the room.

We’re thinking about selling it, and go to a WiiM Sub Pro.

The advantage is that I can move it without cables, and should integrate well with my WiiM Ultra.

Other option will be SVS 3000 micro, with also dedicated app to phase and tune.

Any suggestion between those 2 subwoofers?

The Kali must go, the noise is unacceptable and only disappears when using the 80 Hz internal crossover.

Why don't you buy two deacent cheap big sub's (nothing beets physics)? I read about Kali and peak humm. Supposedly as far as I reed they solve it out later on. They will be big and ugly and work. If for some reason you want separate self DSP depending on availability I would still recommend MiniDSP Flex and go by hand not Dirac, 10 PEQ's per chenel bank should be sufficient. Even if you go with very high end branded sub (KH750 for example) it will still have just average amplifier and there would be some humm especially from AC modulation. That problem you won't resolve without DIY (nor solve better). All of this makes me wonder how bad plate one on Kali is as those are very low efficiency drivers. As much as I remember problem whose more regarding nasty done inputs. I still prefer PC for DSP processor but that's me.

 

[Miguelón]

I'm a little confused. Echolocation actively uses higher frequencies that shouldn't be masked by a subwoofer. Maybe you're using lower frequencies than normal when navigating that can be masked by the subwoofer. Or maybe the subwoofer is broken and producing too high frequencies. A normally functioning subwoofer shouldn't mask echolocation. Or have I misunderstood your problem.

JM

I myself ignore how happens with my ears and vertical orientation.

It exists some research for complete blindness, that’s true echolocation: I had a colleague in the hospital who emitted “clicks” with his tongue and can detect walls distance or if the door is open. However this can only happens in a relatively silent ambience.

In my case, with a neurologic condition that moves constantly my eyes (congenital nystagmus), I have to tilt my head to reduce the tremor by relaxing some of the extraocular muscles.

That creates a conflict between propioceptors (tension and pressure detectors), labyrinth detectors (inner ear) and eyes: those are the 3 system to balance.

With an ear defenders, I loose balance quite easily, so I need ear to preserve vertical position. Nothing happens if I’m comfortably seated and block my ears, so is not a reaction to the hearing loss per se.

When I’m in an ambient with walls and low frequencies present (traffic, a rock concert), my body inclines towards the source if is large.

With an ORL we conjectured that I detect the front wave delay between both ears from various frequencies rebounding from the floor, and calculate the horizontal plane.

Maybe the low frequencies mask the detection or maybe they are the ones I use to balance.

I really don’t know, but the cervical and spine contraction is quite strong: with headphones I walk very rigid, and if the stereo image is good, I automatically put the head aligned with the left-right side: as I should tilt my head to read subtitles in a TV, for example, this creates a tension between my ear reflexes and my visual need.

That’s all I remember now, I use the word “echolocation” for simplicity

 

[Miguelón]

Why don't you buy two deacent cheap big sub's (nothing beets physics)? I read about Kali and peak humm. Supposedly as far as I reed they solve it out later on. They will be big and ugly and work. If for some reason you want separate self DSP depending on availability I would still recommend MiniDSP Flex and go by hand not Dirac, 10 PEQ's per chenel bank should be sufficient. Even if you go with very high end branded sub (KH750 for example) it will still have just average amplifier and there would be some humm especially from AC modulation. That problem you won't resolve without DIY (nor solve better). All of this makes me wonder how bad plate one on Kali is as those are very low efficiency drivers. As much as I remember problem whose more regarding nasty done inputs. I still prefer PC for DSP processor but that's me.

It was a good Erin review of them, linear to 31 Hz or so, reasonably SPL. Nothing I dislike.

AFAIK here in Europe the problem is not solved, maybe for the 12 inch sub, but not for mine.

 

[Pareto Pragmatic]

You may be picking up the port as well. If you have the port pointing into the room, try rotating the sub 180 degrees. Given side firing dual drivers, that should not change the overall sound, but might give you less directed sound from the port.

Worth a try given it takes very little time to do.


NEVERMIND!!!! Just saw that there are front and rear ports, so this would not work. Maybe the sub at a 45 degree angle might help though.

This is what I get for not looking at the sub before posting.

I'm a little confused. Echolocation actively uses higher frequencies that shouldn't be masked by a subwoofer.

I think the issue is more that this is someone who has a lot of time paying attention to echos, and more importantly the direction of sounds in general. Similar to how trained listeners hear more than untrained ones, people who practice navigation by sound are going to pick out more details in sound than those who don't.

 

[Miguelón]

I think the issue is more that this is someone who has a lot of time paying attention to echos, and more importantly the direction of sounds in general

Yes, that’s my case: if some objet falls, for example a coin or a screw, I often know where it went by the sound it made when kicking against the floor and some rebounds.