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Neumann KH310a or KH120a with 805 sub?

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Re: Neumann KH310a or KH120a with 805 sub?

PostPosted: Sat Oct 24, 2020 6:17 pm
by Tomster
RichardT wrote:
Tomster wrote:
blinddrew wrote:Depends if you stuff the closet with rockwool first. ;)

It's basically eaves space that contains boiler and tank. It's pretty deep. I could put fluffy insulation behind the tank and probably put a decent size bass trap in front of the tank and behind /around the subwoofer.

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I’m no expert, and I’m sure others will weigh in if I’m wrong, but I have though you would want as little sound as possible to get into that side space. It will only cause you problems. Some kind of door seals would help, keep the door shut, and put the subwoofer away from the door.

I have no idea if you are right or wrong but why do you think that?

I was planning to seal it actually - I even have the seals here :-)

Re: Neumann KH310a or KH120a with 805 sub?

PostPosted: Sat Oct 24, 2020 7:17 pm
by blinddrew
Sorry, can you confirm the layout of the room, and the closet again please? I've got a bit lost.

Re: Neumann KH310a or KH120a with 805 sub?

PostPosted: Sat Oct 24, 2020 10:18 pm
by Tomster
Hi,

Yes, the room is 3.7m L x 2.4m W x 2.3m H. It's in the loft, and the entrance door is rear left . There is a door mid front wall that leads to the storage space in the roof eaves pictured earlier where the tank is. ceiling is sloped.

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Re: Neumann KH310a or KH120a with 805 sub?

PostPosted: Sat Oct 24, 2020 10:25 pm
by Tomster
Today I did some extra REW measurements at mid way and towards the back of the room and the mid point was actually flatter than the 1/3 points. There is quite a pronounced peak at 45hz when I measured at 38% from front wall that was much flatter at the mid way. All three positions had a consistent drop at ~120hz.

Re: Neumann KH310a or KH120a with 805 sub?

PostPosted: Sun Oct 25, 2020 12:21 am
by blinddrew
My gut feel is that stuffing the cupboard with absorbent stuff will turn it into an effective bass trap, but i'm no expert.

Re: Neumann KH310a or KH120a with 805 sub?

PostPosted: Sun Oct 25, 2020 11:26 am
by Sam Spoons
blinddrew wrote:My gut feel is that stuffing the cupboard with absorbent stuff will turn it into an effective bass trap, but i'm no expert.

But would make access to the boiler and tank somewhat difficult?

Re: Neumann KH310a or KH120a with 805 sub?

PostPosted: Sun Oct 25, 2020 4:43 pm
by blinddrew
Lightly stuff the stuffing into old duvet covers and you can easily drag it in and out for access.

Re: Neumann KH310a or KH120a with 805 sub?

PostPosted: Sun Oct 25, 2020 6:40 pm
by Tomster
blinddrew wrote:Lightly stuff the stuffing into old duvet covers and you can easily drag it in and out for access.


Yes, thats the sort of thing I had in mind, either a bag, hanging from a hook, or a freestanding bass trap on wooden frame I can slide around.

Today I spent £55 on 2 bags of Rockwool RW3 insulation (12 sheets of 75mm 1200mmx600mm) and placed it in two's around the room corners and at the first reflection points.

Smells and looks terrible but Holy Batman - it sounds phenomenal !!

My Mackie's are now sounding better than my Spendor D7s!

Re: Neumann KH310a or KH120a with 805 sub?

PostPosted: Sun Oct 25, 2020 8:39 pm
by RichardT
Tomster wrote:
blinddrew wrote:Lightly stuff the stuffing into old duvet covers and you can easily drag it in and out for access.


Yes, thats the sort of thing I had in mind, either a bag, hanging from a hook, or a freestanding bass trap on wooden frame I can slide around.

Today I spent £55 on 2 bags of Rockwool RW3 insulation (12 sheets of 75mm 1200mmx600mm) and placed it in two's around the room corners and at the first reflection points.

Smells and looks terrible but Holy Batman - it sounds phenomenal !!

My Mackie's are now sounding better than my Spendor D7s!

That’s great news. Rock wool emits formaldehyde so make sure to ventilate the studio.

Re: Neumann KH310a or KH120a with 805 sub?

PostPosted: Sun Oct 25, 2020 8:59 pm
by orbita
RichardT wrote:
Tomster wrote:
blinddrew wrote:Lightly stuff the stuffing into old duvet covers and you can easily drag it in and out for access.


Yes, thats the sort of thing I had in mind, either a bag, hanging from a hook, or a freestanding bass trap on wooden frame I can slide around.

Today I spent £55 on 2 bags of Rockwool RW3 insulation (12 sheets of 75mm 1200mmx600mm) and placed it in two's around the room corners and at the first reflection points.

Smells and looks terrible but Holy Batman - it sounds phenomenal !!

My Mackie's are now sounding better than my Spendor D7s!

That’s great news. Rock wool emits formaldehyde so make sure to ventilate the studio.

Thanks for mentioning it. Is it just temporary?

Re: Neumann KH310a or KH120a with 805 sub?

PostPosted: Sun Oct 25, 2020 9:23 pm
by James Perrett
orbita wrote:Thanks for mentioning it. Is it just temporary?

I hadn't been aware of the issue before but apparently it reduces with time according to

https://www.eurofins.com/media/2266/for ... s_1086.pdf

For bass traps you can leave the Rockwool in its packaging and possibly cover the exposed ends with cling film.

Re: Neumann KH310a or KH120a with 805 sub?

PostPosted: Sun Oct 25, 2020 11:05 pm
by Sam Spoons
My experience is that it doesn't smell much and it is short lived.

Re: Neumann KH310a or KH120a with 805 sub?

PostPosted: Sun Oct 25, 2020 11:08 pm
by RichardT
orbita wrote:
RichardT wrote:
Tomster wrote:
blinddrew wrote:Lightly stuff the stuffing into old duvet covers and you can easily drag it in and out for access.


Yes, thats the sort of thing I had in mind, either a bag, hanging from a hook, or a freestanding bass trap on wooden frame I can slide around.

Today I spent £55 on 2 bags of Rockwool RW3 insulation (12 sheets of 75mm 1200mmx600mm) and placed it in two's around the room corners and at the first reflection points.

Smells and looks terrible but Holy Batman - it sounds phenomenal !!

My Mackie's are now sounding better than my Spendor D7s!

That’s great news. Rock wool emits formaldehyde so make sure to ventilate the studio.

Thanks for mentioning it. Is it just temporary?

Yes it’s quite temporary. Most people are not bothered by it but a few get sore throats or headaches.

Re: Neumann KH310a or KH120a with 805 sub?

PostPosted: Mon Oct 26, 2020 11:35 am
by Hugh Robjohns
The formaldehyde comes from the binders used in the production of most types of Rockwool (and most other equivalents), but most of it disappears during production and it is emitted only at extremely low levels in the finished product -- and lots of other things emit just as much including many forms of timber, most soft furnishings, and even your own exhaled breath! So it's not something to get eye-bulgingly worried about.

Obviously, it makes sense to ensure adequate ventilation in any space fitted with Rockwool (and its equivalents)... and if you're really concerned Rockwool do make broadly equivalent products now that don't use formaldehyde binders -- as do many other equivalent manufacturers.

Re: Neumann KH310a or KH120a with 805 sub?

PostPosted: Mon Oct 26, 2020 11:40 am
by Hugh Robjohns
Tomster wrote:Today I spent £55 on 2 bags of Rockwool RW3 insulation (12 sheets of 75mm 1200mmx600mm) and placed it in two's around the room corners and at the first reflection points.

Smells and looks terrible but Holy Batman - it sounds phenomenal !!

Yes, it's amazing what a difference some acoustic absorption can make!

The smell goes away... but I try to leave the rockwool batts out in the garage for a week or two before use to let that smell disappear before installation. Same goes for commercially made panels.

Regarding your attic space... I'd be quite concerned about that becoming a resonant chamber at the low frequencies your sub will generate -- especially if you plan on placing your sub in the door way! It could potentially make your music room rather boomy and it might well annoy your neighbours considerably, too!

It's impossible to tell from the drawings, so you'll have to experiment... but you may well need to put in extensive bass trapping of one form or another, and be very careful about vibrations from the sub rattling whatever you use to fill the door space!