speaker isolation.... advice

paulmapp8306

Ok, so my monitors are mounted on a raised shelf - actually made from a twin tier keyboard stand - with kitchen worktops mounted on both tiers to for a twin height workstation.

The monitor sit on the upper shelf (no space on the lower).  This puts the woofer at approx ear height - but the tweeter is obviously higher.

I currently use some iso pads, and they have an 8 degree down tilt. This still isnt perfect - I could do with a little more tilt, but there not bad.

As Im upgrading my monitors Im considering Iso stands to replace the pads - however these will add approx 6.5 cm of base height, and the max tilt is 6.5 deg.  so basically more height and less tilt.

For those in the know, is there a way to tilt the stands more somehow?  mixing the leg height, or the tilt risers for instance.  If not, are there any similar products allowing for more tilt angle?   Im guessing I need between 15 and 20 deg down tilt if the stands are 8cm tall.  I know thats a lot.  Or am I better just sticking with the pads?

The speaker sit at the front edge of the shelf though - so even firing down that much they fire into space not at the desktop, and for info, the height difference between the two worktops is approx 29 cm.

Branshen

Dedicated monitor stands are not very expensive (around 40 quid for entry level stuff) and will be height adjustable to solve your problem. Being freestanding, you can adjust their positioning freely to what sounds best. Your setup sounds like a compromise to me. Plus won't tilting speakers that much cause them to be unbalanced and possibly make them fall over?

Whistler

Most speakers are seen with the tweeter at the top and the woofer at the bottom. If you are tilting your speakers down then try having your speakers with the tweeter at the bottom. The acoustic axis of the speaker will be nearer the tweeter and so getting that nearer to ear level will help. Bass frequecies are omnidirectional so it is less important where the woofer is relative to you.

As for isolation, you won't be able to acoustically isolate the speakers from the kitchen worktop so the best option is to dampen them using sorborthane hemispheres of the correct size and durometer for the weight of your speakers.

paulmapp8306

Never thought about tweeter down.  I've had my a5x on their sides as well as upright, but the kh120s dont really allow that as the hd wave guide is oval to allow greater left to right spread and less up and down.

Tweeter down will mean even with iso stands I'd need less down angle to get them pointing at ear height.

Re speaker stands, not an option.  The desktop covers the whole room width so nowhere to put them, and wall mounted brackets would be higher up than the top shelf plus iso mounts

octatonic

Personally I would decouple the speaker from your monitor shelf.
Good stands are expensive- have a look at the prices for the industry standards, such as Sound Anchor ADJ2's.

You generally want a lot of mass in the stand with small contact points for the stand to the ground (ie spikes) and to decouple the speaker from the stand as well.

The problem is that the differences are marginal but noticeable.
I have my two sets of monitors on ADJ2's, with ISO pucks between the speaker and the stand.

There is no point in doing any of this without decent acoustic treatment in the room though.

paulmapp8306

Room has some treatment, but there isnt room for more for various reasons.

Stands arnt an option.  Speakers are already too high really.

It's the iso 155 product I'm considering which is a push height wise already.

The top shelf does have some decoupling from the stand arms but it's a chunky bit of wood itself.

As long as there is a small but noticeable difference in the lf without compromising direction to ear I'll be happy.

Got to say the comment on lf sounds being omnidirection isnt true.  All waves are as directional as each other.  What changes is the human ears capability to determine the direction the wave is comming from.  The lower the freq the worse the ability.  Picky maybe as the resulting effect is the same, but still.

PolarityMan

paulmapp8306 said:

Never thought about tweeter down.  I've had my a5x on their sides as well as upright, but the kh120s dont really allow that as the hd wave guide is oval to allow greater left to right spread and less up and down.

Tweeter down will mean even with iso stands I'd need less down angle to get them pointing at ear height.

Re speaker stands, not an option.  The desktop covers the whole room width so nowhere to put them, and wall mounted brackets would be higher up than the top shelf plus iso mounts

Hmmm I need to have my speakers a touch too high and angled down so that they clear my screen mounts meaning the tweeter is about 8 inches above my head in the listening position. I wonder if turning the speakers on their side would help here for me too.

How did you wind the info on the wave guide?

paulmapp8306

OK - got some Iso 155s to try.   I cheated a little, because I fitted both the little risers (there are two sizes for two angles) one at each end of the back tubes - so I actually get nearer 10 deg angle (I believe there designed for 3.5 degree and 6.5 degree respectively - so fitting both gives 10 deg).  I have the small bars fitted to both front and back (rather than big ones at the back)

Turning the speakers upside down (tweeters down) actually puts them directly pointing at my ears in my listening position (sitting them in the normal orientation and the tweeters point just over the top of my head).  It looks a little odd - but only because its not a normal look (and the Neumann logo is upside down) - and Im going to have to come up with a cable management solution as the KH120s have the power and signal cable connectors mounted downwards normally (rather the straight out of the box) meaning in the upside down position the cables point straight up upwards - but I can sort a hook system on the back way to provide some strain relief.  

Sound wise, theres actually a very distinct improvement from the pads as well - the bass is tighter and has more definition.  

Just need to find how to properly calibrate the KHs now I have them on iso pads (that is the bass/mid/treble switches).  

paulmapp8306

OK - pink noise / spectrum checked and a feq sweep done as well.

My room has a big dip (cancellation) at 110 and less so at 220 hz (obviously double the freq).  Its huge....   Theres also a bump around 60hz - but thats the sub.  The KHs have a low fre (quoted) of 52 hz, but the lowest freq the subs low pass goes to is 80hz, so that 60hz is where the mains really kick in but the sub is still full on.  I did have to raise the subs volume a touch from where it was when using iso pads - I guess thats the result of tightening the low end with the isolation stands.

I can solve it for playback (in media player) with a 4db cut at 62hz and a 5db raise at 120hz.  Its then pretty flat (from the pink noise played via media player).   Ill do the same test from my DAW later.  This is all at 85db give/take.

To achieve this, I have the KHs freq controls set with mid level flat, a 2,5bd cut on the low and a +1db rise on the highs - otherwise anything over 5k drops.

Bass is much tighter than without the isos, and theres more clarity.  The stereo imaging and depth of the sound field is a lot better with the KHs compared to the A5Xs (got them out to A/B).

I need to remember those 60/110/220 hz bumps/curts when I mix and need to work out how to minimise them (especially the cuts).  Im assuming there reflections from the rear wall because moving the speakers doesnt change it - and moving position only moves the freq slightly - unless Im stood flat against the rear wall.

Cant use any damping on the wall itself as its the only storage (wall cabinate) space - but could do something in the top corners and along the wall/ceiling join IF thats gong to help (might not mind if its reflections from the flat rear wall itself).  Opening the door to 45 deg (which is in one rear corner) does help though - it reduced the amount of cut I see - so maybe treating those wall/ceiling boundaries might be worth a go.

I will say - I only ever mix my own stuff, for fun - and occasionally band stuff (mine and friends) again though only for self consumption, so its not worth ripping the room apart (and its a small room as well).  Actually taking the known issues into account when mixing - and checking on my AKG702s (which obviously dont have those issues) may well yield perfectly decent results. 

paulmapp8306

PolarityMan said:

paulmapp8306 said:

Never thought about tweeter down.  I've had my a5x on their sides as well as upright, but the kh120s dont really allow that as the hd wave guide is oval to allow greater left to right spread and less up and down.

Tweeter down will mean even with iso stands I'd need less down angle to get them pointing at ear height.

Re speaker stands, not an option.  The desktop covers the whole room width so nowhere to put them, and wall mounted brackets would be higher up than the top shelf plus iso mounts

Hmmm I need to have my speakers a touch too high and angled down so that they clear my screen mounts meaning the tweeter is about 8 inches above my head in the listening position. I wonder if turning the speakers on their side would help here for me too.

How did you wind the info on the wave guide?

The info on the guide is on Neumanns website and noted in many of their promotional vids on the KH 80/120s.

paulmapp8306

Even listening to some of my favourite tracks (through media player with those couple of EQ adjustments..... Its so much more immersive and Im hearing things Ive NEVER heard before.

Tracks of note are "Tears for Fears "Women in Chains", Duran Duran "The Chauffeur"  and Depeche Modes "World in my Eyes".

Winny_Pooh

Personally, I'd hate your setup. I like monitors not angled. That way I can move closer and further away to get a different feel for how the centre channel is balanced w left & right without the highs then disappearing. Plus it's useful to hear the low end change depending on your position.

Re the dips, how close are your speakers to the wall and is it totally solid? Try moving them a bit away and see if you get less wavelength cancellation. 

I use iso-acoustic stands with my kh120s and they're fine. Great monitors. 

paulmapp8306

Ive tried moving the monitors as close, and as far as I can from the walls.  Seems to make no difference.  I think its the reflection from the far wall cancelling with the original from the speaker (1/4 wave cancellation I think)..

Ive never though of NOT angling the speakers.  Pretty much EVERYTHING Ive ever seen, be it Hifi, surround or studio monitor placement recommends the equilateral triangle system to the listening position - and with the tweeters firing at ear height..  Of course people listening to your mix arnt going to be doing that in many cases.... or always if there on headphones. 

The angling down is purely so the tweeters fire at my ears - its a necessity given the space and the amount of kit I have to get in (its not just my recording space, Its my guitar practice space, my keyboard practice space, my Gaming space, my workspace when at home, and mu general PC based space).

Might try not Toeing them in as much (so I can still get the direct fire but at a further distance) and/or not angling them down (tweeters still woundnt be too far above my ear height - and I could always stand up.....)   Anything/everythings worth a go.