I posted this on a UK forum. I thought it might be useful for the Monolith owners I've noticed on here and anybody else with a down firing sub with, shall we say, an active floor covering.
I have a laminate wood floor which is foam backed on a suspended concrete floor. Coupled with the relatively hard surface of the rest of the room, leather sofas etc, I thought I'd try and tackle the floor interaction by deflecting some of the acoustic and mechanical output from the Monolith, thereby taming some of the in-room peaks that I suffer.
I have no shame in suggesting that I got the idea from the base panel of the SVS box subs. I don't see why it should'nt work for any down firing sub although, obviously, the panel dimensions would have to be adjusted to suit your sub. All references are to UK suppliers and measurements which are metric, as they should be in this day and age:devil:
It should also be noted that I have a BFD which I am prevented from taking possession of until my birthday on June 2nd. I was bored and reckoned that anything that could help wouldn't hurt things once the BFD is up and running.
For this I bought a 450x420x19mm panel of MDF. Hombase supplied this cut to size. They were accurate in the size if not in actually charging me for the wood. The fact that it was amongst about 15 matchpots of paint my wife had chosen may have helped.
Jpeg 1. Turn the DF upside down and align the panel acurately on the upturned spikes. Once you're happy, press down hard. You now have perfectly aligned pilot holes for the drilling that follows. Look carefully and you can just see them.
Jpeg 2. You will need some M8x25mm bolts and some 25mm washers. Now I look at my receipt again, I can't see these on there either - This keeps getting cheaper! All in they were supposed to be about a couple of quid.
Jpeg 3. Using the 25mm wood drill and the pilot holes, drill a hole deep enough to recess the head of the bolt and the 25mm washer. I used the 25mm washer to prevent the bolt crushing the MDF when everything is tightened up when bolting to the DF. The washers in the bolt pack are inadequate. Turning the bolt and washer upside down, as shown, allows you to judge when this is about right. Once happy, drill the center of the hole with an 8mm wood bit. The DF spike holes are 8mm hence the requirement for 8mm bolts.Sand the edges and corners of panel to suit. I did my best to approximate to the radius of the Monoliths edges and upon refection, I could've done a bit more, but I'm no pro.
Jpeg 4. Spray the panel with ordinary grey primer for cars (Mine came from Halfords). MDF absorbs quite a lot of paint and I sprayed 3 coats with light sand papering (240 grade) after each to achieve a smooth finish. The edges in particular need quite a lot of attention to get smooth, as the paint tends to exagerate the particle nature of the board. I sprayed the 2 top coats in Halfords Citroen Arctic Silver - it was the best match to my Atacama stands, from memory. I sanded lightly after the first coat again. It's worth noting that you will never see the bottom of the panel, nor the middle of the top, so pay your attention to the edges. This image is of the primed panel.
Jpeg 5. This image looks like poop. The camera flash is really unforgiving, but I may well apply another can of the silver to get a perfect finish. From my listening position it looks to be a decent match to my Atacama stands and it looks shiny. You can see the panel bolted in place and one of the Focul Polidods which I placed directly over the bolt hole. They are exactly the same diametre as the DF feet which is a happy coincidence and serve to decouple any mechanical energy from the floor. I used a touch of carpet tile spray to hold them in place, but anything from Prit Stik upwards will work. Placing my hand on the floor next to the sub whilst playing shows no vibration from the floor. Plenty of air is moving over the back of my hand however. I used 4 of the large Polipods, one at each corner, plus one small spare Polipod in the center of the panel. The four big ones compress enough under the weight of the DF that the small one also touches the floor. It's a bit 'belt and braces' but by their nature the 'Pods', whilst isolating the DF from the floor, also absorb any resonance within the panel. So no harm there then.
Jpeg 6. DF, right side up fixed to panel. Overall height is about the same as with the spikes fitted. The same arrangement will work with spikes fitted if you are on a carpeted floor, but you would need to source spikes with a longer thread as they first have to pass through about 10mm of MDF plus the 25mm washer before reaching the thread in the feet.
End result, visually you decide. Paint it any colour you like to match your decor, or not at all if you can't be arsed! Aurally, in my room at least, there is a definite tightening of the bass. I assume this is due to the supression of the floors contribution. The once slightly overpowering upper sub bass is now tamed and as a result, I have turned the DF up slightly. This has allowed the lower frequencies to step up a notch, which has increased the perceived depth of the bass response.
All of this was already there, I haven't added anything to the audio chain, but a bit of subtraction has added to the overall effect in a very positive way. God knows what difference the BFD is going to make with active equalisation, if this is the difference £20 of wood, bolts and a little time can make.
Give it a wizz. If it makes no difference, so what? It's the price of a very average interconnect that can make things sound worse.
Edit: For some reason (I'm an idiot?) Jpeg1 is the last image and Jpeg2 is the first.
Russell
I have a laminate wood floor which is foam backed on a suspended concrete floor. Coupled with the relatively hard surface of the rest of the room, leather sofas etc, I thought I'd try and tackle the floor interaction by deflecting some of the acoustic and mechanical output from the Monolith, thereby taming some of the in-room peaks that I suffer.
I have no shame in suggesting that I got the idea from the base panel of the SVS box subs. I don't see why it should'nt work for any down firing sub although, obviously, the panel dimensions would have to be adjusted to suit your sub. All references are to UK suppliers and measurements which are metric, as they should be in this day and age:devil:
It should also be noted that I have a BFD which I am prevented from taking possession of until my birthday on June 2nd. I was bored and reckoned that anything that could help wouldn't hurt things once the BFD is up and running.
For this I bought a 450x420x19mm panel of MDF. Hombase supplied this cut to size. They were accurate in the size if not in actually charging me for the wood. The fact that it was amongst about 15 matchpots of paint my wife had chosen may have helped.
Jpeg 1. Turn the DF upside down and align the panel acurately on the upturned spikes. Once you're happy, press down hard. You now have perfectly aligned pilot holes for the drilling that follows. Look carefully and you can just see them.
Jpeg 2. You will need some M8x25mm bolts and some 25mm washers. Now I look at my receipt again, I can't see these on there either - This keeps getting cheaper! All in they were supposed to be about a couple of quid.
Jpeg 3. Using the 25mm wood drill and the pilot holes, drill a hole deep enough to recess the head of the bolt and the 25mm washer. I used the 25mm washer to prevent the bolt crushing the MDF when everything is tightened up when bolting to the DF. The washers in the bolt pack are inadequate. Turning the bolt and washer upside down, as shown, allows you to judge when this is about right. Once happy, drill the center of the hole with an 8mm wood bit. The DF spike holes are 8mm hence the requirement for 8mm bolts.Sand the edges and corners of panel to suit. I did my best to approximate to the radius of the Monoliths edges and upon refection, I could've done a bit more, but I'm no pro.
Jpeg 4. Spray the panel with ordinary grey primer for cars (Mine came from Halfords). MDF absorbs quite a lot of paint and I sprayed 3 coats with light sand papering (240 grade) after each to achieve a smooth finish. The edges in particular need quite a lot of attention to get smooth, as the paint tends to exagerate the particle nature of the board. I sprayed the 2 top coats in Halfords Citroen Arctic Silver - it was the best match to my Atacama stands, from memory. I sanded lightly after the first coat again. It's worth noting that you will never see the bottom of the panel, nor the middle of the top, so pay your attention to the edges. This image is of the primed panel.
Jpeg 5. This image looks like poop. The camera flash is really unforgiving, but I may well apply another can of the silver to get a perfect finish. From my listening position it looks to be a decent match to my Atacama stands and it looks shiny. You can see the panel bolted in place and one of the Focul Polidods which I placed directly over the bolt hole. They are exactly the same diametre as the DF feet which is a happy coincidence and serve to decouple any mechanical energy from the floor. I used a touch of carpet tile spray to hold them in place, but anything from Prit Stik upwards will work. Placing my hand on the floor next to the sub whilst playing shows no vibration from the floor. Plenty of air is moving over the back of my hand however. I used 4 of the large Polipods, one at each corner, plus one small spare Polipod in the center of the panel. The four big ones compress enough under the weight of the DF that the small one also touches the floor. It's a bit 'belt and braces' but by their nature the 'Pods', whilst isolating the DF from the floor, also absorb any resonance within the panel. So no harm there then.
Jpeg 6. DF, right side up fixed to panel. Overall height is about the same as with the spikes fitted. The same arrangement will work with spikes fitted if you are on a carpeted floor, but you would need to source spikes with a longer thread as they first have to pass through about 10mm of MDF plus the 25mm washer before reaching the thread in the feet.
End result, visually you decide. Paint it any colour you like to match your decor, or not at all if you can't be arsed! Aurally, in my room at least, there is a definite tightening of the bass. I assume this is due to the supression of the floors contribution. The once slightly overpowering upper sub bass is now tamed and as a result, I have turned the DF up slightly. This has allowed the lower frequencies to step up a notch, which has increased the perceived depth of the bass response.
All of this was already there, I haven't added anything to the audio chain, but a bit of subtraction has added to the overall effect in a very positive way. God knows what difference the BFD is going to make with active equalisation, if this is the difference £20 of wood, bolts and a little time can make.
Give it a wizz. If it makes no difference, so what? It's the price of a very average interconnect that can make things sound worse.
Edit: For some reason (I'm an idiot?) Jpeg1 is the last image and Jpeg2 is the first.
Russell
