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What is the most dramatic way of increasing a speaker's Bass and Low mid?

Hi-

I am wondering what would give the most dramatic increase in bass and low mid projection/Volume, even on account of accuracy ...


My speakers can go down to 28hz but i need to boost it’s level, not frequency extension. They are 2 way with bass reflex port. 6.5" woofer size and a tweeter. Floor standing.

My floor is old hardwood strips.

placement and coupling methods are the first things that come to mind. I do not want to add an equalizer at this point.

Spikes, footers, concrete platform, direct floor flush contact? anything and everything that YOU know works.
Speculations on untested methods are not needed as i need real life experience from people.

Thanks!
Rea

128x128dumbeat

Showing 6 responses by dgarretson

dgarretson
2,394 posts
 

I don’t find my VSMs short on bass, low midrange, or macro-dynamics in a medium sized 20’ x 14’ room with a 7.5’ ceiling. IIRC, the BBAM adds +5db at 35hz and rolls off entirely below 28hz. There is a bit of port effect reinforcement below 30hz.

There is nothing in Stereophile’s measurements to account for the OP’s experience-- except for a roll-off in the 2hz crossover region on axis with the tweeter. (Response is flat with ear positioned at the level of the top of the woofer basket.) You might check for DC output on the BBAM. The woofers can be damaged if the op amps in the BBAM fail to DC and the owner’s amp doesn’t block DC.

https://www.stereophile.com/content/merlin-music-systems-vsm-millennium-loudspeaker-system-measurements

dgarretson
2,394 posts
 
Doug, the elegance of the Merlin VSM/BBAM design was that a Scanspeak 8545 driver has sufficient excursion to be EQ’d into a full-range midrange/bass driver, provided that the EQ fully attenuates frequencies below 30hz. Its admittedly constrained dynamics at high volumes for large rooms is the price that one pays for the coherence of a crossoverless point-source from 30hz to 2Khz.  As digital crossovers and equalizers were mediocre in those days, the analog BBAM was the ticket.
dgarretson
2,394 posts
 

Actually, one way to embellish and raise output of the Scanspeak 8545 mid/woofer relative to the Esotar tweeter is to add a Scanspeak bucking magnet. This doubles the 8545's magnet structure and raises output by several db-- as suggested by Tony Gee of Humble HiFi, who did this with 8545s in some project speakers.  I followed him with this mod in my VSMs.  Another improvement is to power the BBAM with a higher quality +/- 12V LPS than the batteries or AC supply in the stock unit.

dgarretson
2,394 posts
 
Rough sand off the lacquer coating the perimeter of the steel plate that covers the stock magnet. Rough sand the mating surface of the donut shaped bucking magnet. Place the driver face down on a level surface. Thinly coat both surfaces with 5 minute strong epoxy. Apply the bucking magnet in the correct direction. (It will be repelled as it approaches the stock magnet and attracted when in close proximity.) Make minor adjustments to align the magnet as the epoxy stiffens to ensure that the two magnets are concentric with each other and thus the voice coil.
dgarretson
2,394 posts
 
I've been all over the VSMs: LPS for BBAM, replacement of stock Hovland mylar caps in crossover with ClarityCap CMR, replacement of stock Caddock resistors with TX2575s and Dueland graphite resistors, bucking magnet on the 8545, silver wire inside, buffalo felt around the tweeter domes, Stillpoint footers, steel microbearing instead of sand in the cabinets.  You likely won't get to any of this, but each step is a meaningful refinement.   
dgarretson
2,394 posts
 

Bobby liked them around 6.5’ apart, the listener around 9.5’ from each speaker, and a bit more toe in than you might expect. Stay fairly close to that.

Also, periodically clean tarnish off the bare copper binding posts and torque down the screws on the drivers.

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