Mass loading Tannoy Definition DC10a speaker.

My Cornwall 4's are easy to mass load from the bottom because of the 3 bass ports at the bottom facing forward. I used lead weights and found that at some point weight became counter-productive and actually boosted and distorted treble. The sweet spot was about 18 lbs of lead per box. More weight stiffened the walls of the box too much and perhaps contradicted some of the resonance designed into the speakers in the first place.

Mulveling, my experience with the DC10a is that it is balanced and warm top to bottom when I am not using the spike(just let them rest on carpet), I have very detailed bass, every note is there and it rattles the floor (in a good way I mean). Bass is full but the very deep bass(<40 hz is not that impactful but you hear the note clearly). Overall, it is a very visceral experience. When I put them on the spikes, the sound is a bit more detailed, and may lean towards being bright but not much. They sounded best with isoacoustics isopucks underneath them. 

I previously owned a Rel Gibraltar 2, and the deep bass was very deep-the thump- ( I know I am not comparing apples to apples here, but just to make my point)

Bolong, I totally understand, and this is my concern. It may be too much of a good thing, that is why I started this thread. The other concern, if I don’t like it, it is very hard to get the sand (or anything else) out, since the opening is about 2 inches and the box is bigger, there will be some residual sand there. If it is lead shots or atakama atabites, if may be easier to drain. I can’t shake a 100+ lbs speaker (like a salt shaker)  to get the sand out of the circular 2-inch port J

The other issue is that I liked the isopucks and I may buy GAIA II which support up to 120 lbs speakers. If I load beyond 120 lbs, then the GAIA IIs will be useless, and I have wasted $600.

Maybe I can start gradual mass loading, 2 pounds at time, and see where the sweat spot is. If I exceed and want to go back, I have pull back to the previous weight (sweet spot) and leave it there. I was hoping for someone to tell me this weight, so I don’t have to guess nor do this experiment. Tannoy has R & D and they should have provided some guidance rather than an empty compartment and a few lines in the manual about mass loading.

Thanks again

Whatever you try, make sure to enclose it in a strong  "bag"  for easiest removal/testing.

Thank you so much Slaw, This Is a brilliant idea. I can even use multiple small

size bags in increments so they are easier to get of the access port. Thanks 

What are your components up stream?