I knew this was going to happen, when making my new ported speakers with 15" going flat to 25 Hz and each powered by 400 Watts 
My Lenco CD-player can't handle the vibrations at higher volumes, and shuts down momentarily
My house has a wooden floor where the speakers are placed, the CD-player is placed in a rack on the same floor (I know! Not the best solution)
Has one of you experienced the same problem, and found a good solution ?
Back in time, when LP's was the source I had my turntable hanging from the selaing placed in a sand filled box and with rubber bands as vibration absorbers
Worked just amazing but not a pretty sight
My Lenco CD-player can't handle the vibrations at higher volumes, and shuts down momentarily
My house has a wooden floor where the speakers are placed, the CD-player is placed in a rack on the same floor (I know! Not the best solution)
Has one of you experienced the same problem, and found a good solution ?
Back in time, when LP's was the source I had my turntable hanging from the selaing placed in a sand filled box and with rubber bands as vibration absorbers
Worked just amazing but not a pretty sight
Hi Jan,
This one of the most fun and cheap parts of DIY. I've messed around with rubbber bouncing balls, squash balls, sand trays, inner tubes, concrete slabs ...... but have finally settled on large sorbothane feet for convenience. Most methods work quite well but I like the idea that sand and sorbothane doesn't resonate like rubber. I did have fun experimenting though.
Do you think that some of the problem could also be airborne and require mass tuning or repositioning away from resonant spaces?
This one of the most fun and cheap parts of DIY. I've messed around with rubbber bouncing balls, squash balls, sand trays, inner tubes, concrete slabs ...... but have finally settled on large sorbothane feet for convenience. Most methods work quite well but I like the idea that sand and sorbothane doesn't resonate like rubber. I did have fun experimenting though.
Do you think that some of the problem could also be airborne and require mass tuning or repositioning away from resonant spaces?
Hi Sonusthree
Frankly I´m afraid that some of my problems are also airborne due to the lhigh output and very low frequency (at 20-25 Hz).
I will start with trying some different ways to isolate the CD-player from vibrations from the floor, and if thats not working, I have to go the "long way" and try to repositioning the CD-player (which isn't easy, when the wife also has something to say c )
Frankly I´m afraid that some of my problems are also airborne due to the lhigh output and very low frequency (at 20-25 Hz).
I will start with trying some different ways to isolate the CD-player from vibrations from the floor, and if thats not working, I have to go the "long way" and try to repositioning the CD-player (which isn't easy, when the wife also has something to say c
)
Hi Jan, I hope you are well.
Repositionig may not be absolutely necessary.
It would be interesting to use a test tone disc and find out which frequencies are the problem. Then, you could see how added mass (from self adhesive bitumen to concrete!!) or mechanical isolation helps.
You have a very interesting problem to solve here. Me, I just try to make it sound a little better but you have a pretty black or white goal to achieve.
More mass will help the airborne problem or at least shift it to a less problematic frequency.
Mechanical isolation would definitely help as long as it is, itself, non resonant.
Mechanical damping: Try bitumen (dynamat or similar) on the case panels. The constrained layer damping will help to dissipate some energy. Try some bags filled with sand in any safe space you have inside the player.
You should definitely experiment. It would be great to have a stethoscope and listen to the different surfaces of your player and your rack.
It reminds me of trying to D.J. vinyl in clubs when I was a little younger. The ultimate aim was to whip the crowd into a frenzy on the dance floor but some venues had badly designed suspended wooden flooring.
More excited dancing people = More jumping needles. It was sometimes a mess. Most places had concrete slabs under the decks or big and wobbly foam pads!! It wasn't pretty but it did usually work. I like your idea of elastic though.
I try to isolate my player from vibrations as much as reasonably possible. I'm not really sure that it's necessary but it just makes sense somehow as long as it's not expensive.
I'll post a couple of pics later.
Regards,
Martin.
Repositionig may not be absolutely necessary.
It would be interesting to use a test tone disc and find out which frequencies are the problem. Then, you could see how added mass (from self adhesive bitumen to concrete!!) or mechanical isolation helps.
You have a very interesting problem to solve here. Me, I just try to make it sound a little better but you have a pretty black or white goal to achieve.
More mass will help the airborne problem or at least shift it to a less problematic frequency.
Mechanical isolation would definitely help as long as it is, itself, non resonant.
Mechanical damping: Try bitumen (dynamat or similar) on the case panels. The constrained layer damping will help to dissipate some energy. Try some bags filled with sand in any safe space you have inside the player.
You should definitely experiment. It would be great to have a stethoscope and listen to the different surfaces of your player and your rack.
It reminds me of trying to D.J. vinyl in clubs when I was a little younger. The ultimate aim was to whip the crowd into a frenzy on the dance floor but some venues had badly designed suspended wooden flooring.
More excited dancing people = More jumping needles. It was sometimes a mess. Most places had concrete slabs under the decks or big and wobbly foam pads!! It wasn't pretty but it did usually work. I like your idea of elastic though.
I try to isolate my player from vibrations as much as reasonably possible. I'm not really sure that it's necessary but it just makes sense somehow as long as it's not expensive.
I'll post a couple of pics later.
Regards,
Martin.
I made this very simple isolation board from two cheap pine shelves back to back. Perhaps pine is a little resonant but it was very cheap and looks quite good. It rests on cut rubber balls.
I don't use it any more because the CD player already has sorbothane feet but this particular sorbothane leaks brown liquid and the shelf is there to stop me being shouted at!!!
I don't use it any more because the CD player already has sorbothane feet but this particular sorbothane leaks brown liquid and the shelf is there to stop me being shouted at!!!
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My amplifiers rest on a Cyrus Isoplat which is a Fibreboard/MDF panel with sorbothane/metal cup feet. This makes more sense since the fibreboard is 'lossy' and less resonant. The idea of sorbothane is very interesting since it is a visco - elastic material and possesses many of the properties of a liquid. It's worth noting that sorbothane comes in different grades and the Isoplat's sorbothane is much harder than the stuff under my CD player.
Best regards,
Martin
Best regards,
Martin
Attachments
I've made a kind of prototype - I bought some round neodynium magnets to use to attach speaker grills but they were way too powerful so tried to find something to do with them and ended up making a kind of magnetically sprung bit of MDF for some reason
I haven't tried it as an isolation platform in practice - I've actually taken it to bits now - it should work fine but I think the bottoms of the bolts will need fixing in place.
I haven't tried it as an isolation platform in practice - I've actually taken it to bits now - it should work fine but I think the bottoms of the bolts will need fixing in place.
one suggestion for a cheap DIY suspension was to buy a hemmrhoid donut (innertube).
on my bike system, i just wrapped some velcro tape around the bungee cords holding the small basket down and stick my CD player to it. i've never had a skip.
the nice thing about bungee cords is that you can get them at a dollar store and tune them by tension. for a home system though, you'd need to build some sort of frame to raise the cords and to stretch them.
the donut solution is simpler and possibly cheaper.
if cost isn't an option, you might want to look into sorbothane pucks. sorbothane has the highest energy absoption ratio of any material on the planet.
at the other end of the spectrum, you could also try mass loading. make the base too heavy to vibrate easily. you could use bricks or even sand/lead loading your platform.
you can even combine the two techniques. mass load your platform and use isolation damping on top.
on my bike system, i just wrapped some velcro tape around the bungee cords holding the small basket down and stick my CD player to it. i've never had a skip.
the nice thing about bungee cords is that you can get them at a dollar store and tune them by tension. for a home system though, you'd need to build some sort of frame to raise the cords and to stretch them.
the donut solution is simpler and possibly cheaper.
if cost isn't an option, you might want to look into sorbothane pucks. sorbothane has the highest energy absoption ratio of any material on the planet.
at the other end of the spectrum, you could also try mass loading. make the base too heavy to vibrate easily. you could use bricks or even sand/lead loading your platform.
you can even combine the two techniques. mass load your platform and use isolation damping on top.
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