Blocking hot tub pump noise in garden?

MMDXL

Hi everyone
One of my neighbours has an inflatable hot tub in his garden - and the pump is causing a low electrical humming noise which can be clearly heard in my garden two doors down (about 50 ft away). We've had a chat with them and discovered the noise is the result of vibrations from the pump hitting a nearby wooden fence (about 3ft from the pump), which appears to be amplifying the noise, it's then carried to a second wooden fence between me and my next-door neighbour, which is amplifying it again. You can't actually hear much in the garden where the pump is situated, but by the time it reaches us, it's a pretty horrible noise, audible right across the garden.
The neighbours seem to be reasonable people and have said they'll see what they can do about fixing the problem but aside from occasionally turning the pump off, nothing has changed in over a month. We've asked if they can perhaps turn the hot tub around so the pump isn't close to the fence but they say this won't work for them (something to do with the way their garden is laid out).
Does anyone know if there's anything I can do on my side of the fence to mask or stop the noise? I've read about acoustic fencing - does anyone know if it works against low-frequency noise? 
I'm pretty upset, as I love my garden - but the constant humming noise is driving me potty to the point I have to put earplugs in before I can go out there! 
By the way, from looking on other hot tub-related threads, I can see they can be rather polarising! I have nothing against hot tubs and anyone who likes them - I just want to be able to enjoy my garden again.
Thanks in advance.

Davesnave

Have you invited these 'reasonable people' round to hear the noise in your garden? They will only act reasonably if they believe there is a problem, so hearing the noise first hand will form a strong element in that belief.

TELLIT01

Rubber matting under the pump would reduce vibration if that is the cause of the noise.  If it is the pump itself which is making the noise, some sort of housing for the pump with sound deadening in that might help.  They would have to make sure that the pump doesn't over heat if they do try to enclose it.

rob7475

Agree with above. Rubber matting under the pump should help dampen vibration. We've got a lazy spa and the pump is barely audible. If it's vibrating that loudly, I'm guessing there's a fault with it

MMDXL

Hi and thanks for the replies.
Yes we've invited them round to listen - but they've declined. 
They already have rubber matting under the pump but we can still hear it. As I said, it's barely audible in their garden - but by the time it reaches us, it's been amplified by two wooden fences.
I think moving the pump right away from the fence would solve the problem but they appear unwilling to do this. So I'm stuck with what I can do to minimise the impact... aside from moving house (which I'd rather not have to do because of someone else's inflatable hot tub), does anyone have any ideas?

Thanks again 

rach_k

Is their next door neighbour being annoyed by it too?  If they are, they might have more luck convincing them to sort it.  

My neighbour has a hot tub against the fence between our gardens.  If they left the pump going when they weren't using it and it was causing a nuisance, I'd be removing the fence panel for some quiet!  I'd probably remove the panel if another neighbour was being annoyed by it too, and tell them it would be going back once they sorted the noise.  Not sure they'd appreciate me sitting chatting to them while they're in their hot tub!

Davesnave

MMDXL said:

 does anyone have any ideas?

Isolating the fence panels by putting in an extra post leaving a 50mm gap and shortening the affected panel.

Or if you want to up the anti, 20w portable speaker pointing their way linked to contact mike on fence.

Apodemus

Davesnave said

Or if you want to up the anti, 20w portable speaker pointing their way linked to contact mike on fence.

Way too subtle!  I’d go with a much larger speaker and hit them full belt with the Glasgow Police Pipe Band at 06.00 for a few mornings!

MMDXL

rach_k said:

Is their next door neighbour being annoyed by it too?  If they are, they might have more luck convincing them to sort it.  

My neighbour has a hot tub against the fence between our gardens.  If they left the pump going when they weren't using it and it was causing a nuisance, I'd be removing the fence panel for some quiet!  I'd probably remove the panel if another neighbour was being annoyed by it too, and tell them it would be going back once they sorted the noise.  Not sure they'd appreciate me sitting chatting to them while they're in their hot tub!

I believe they can hear the hum and find it annoying but they have worse problems with music and other noise coming from that property.... which doesn't bother us so much as we;re that bit further away.... 

Apodemus said:

Davesnave said

Or if you want to up the anti, 20w portable speaker pointing their way linked to contact mike on fence.

Way too subtle!  I’d go with a much larger speaker and hit them full belt with the Glasgow Police Pipe Band at 06.00 for a few mornings!

Ha ha yes don't tempt me!! 

Davesnave

Apodemus said:

Davesnave said

Or if you want to up the anti, 20w portable speaker pointing their way linked to contact mike on fence.

Way too subtle!  I’d go with a much larger speaker and hit them full belt with the Glasgow Police Pipe Band at 06.00 for a few mornings!

Ah, but that wouldn't be true feedback, unless they had said band in their garden.

 But as these clearly aren't reasonable people at all, I wouldn't bother with that, just clamp your own speaker to the fence and give them Rolf Harris's didgeridoo; annoying and politically incorrect!