Synthesis LM-310 Speakers

[whnay1]

Also a MF2550 would improve your bass. but try rotating the woofers 180 degress and it will improve things...

[AnotherJohnson]

Also a MF2550 would improve your bass. but try rotating the woofers 180 degress and it will improve things...

[c-jman]

I have a pair of LM300’s. Specs; fr (-3db):30Hz-20kHz. Sensitivity: 90dB/W/m. Impedance: 8 ohms. Size: 14x15x44, 90 lbs.10” Focal reflex-loaded woofer, top-end rolloff at 100Hz with a 12db/octave Bessel low-pass filter. 7” Focal midrange rolling off at 85Hz with no high-pass network. Mid-to-high crossover set at an unusual point-1250Hz using a 12dB/octave Bessel filter. Tweeter is a 1” Dynaudio. As per Thomas J. Norton Stereophile, VOL.10, NO. 7 (Oct. 1987). My understanding is that the only difference between the 300 and 310 models were the 300’s are cloth covered, mine in cream.

[admin]

Wow. Those look to be in some great shape for their age. Any issues with the cones deteriorating? I had that happen with some older speakers that were made in the 80's.

[whnay1]

Those are in great shape!

If you need new surrounds on the drivers contact Music Technology and ask for Bill Thalmann. They can rebuild the drivers.

The LM310’s used a different woofer. The same as used in the SRS Woofer towers.

Wonderful speakers. I loved mine.

Bill

[whnay1]

Dave Fokos designed these speakers along with Bill Conrad and Lew Johnson. Dave actually built the prototype pair in the basement of my house.

They had remarkable bass solid into the low 30's. The transparency of the LM300's was remarkable as they presented a focused soundstage and extended highs.

Do try rotating the woofer and midrange drivers 180 degrees as that often repositions the voice coil as they can sag over time - just like me.

[AnotherJohnson]

Dave Fokos designed these speakers along with Bill Conrad and Lew Johnson. Dave actually built the prototype pair in the basement of my house.

They had remarkable bass solid into the low 30's. The transparency of the LM300's was remarkable as they presented a focused soundstage and extended highs.

Do try rotating the woofer and midrange drivers 180 degrees as that often repositions the voice coil as they can sag over time - just like me.

Great story! Thanks for all the good inside info!

[whnay1]

I still use my Synthesis SRS speakers. They have the fastest deep bass I have ever heard.

I updated the crossover to Teflon caps and Cardas wiring. Huge difference. Plus I replaced the Dynaudio tweeter with a nice ribbon tweeter. The Dynaudios are almost impossible to find.

The ribbon is very nice.

I also updated the electronic crossover with Teflon caps as well.

[c-jman]

My LM300’s still sound fantastic. I have had no issues with the cones, but will rotate them as suggested. They do need to be reclothed, but so far have not found the correct color cloth. Familiar with Bill Thalmann as he recently rebuilt my PV5.

[whnay1]

Thalmann is great. I have known him since 1978.

The cloth for the LM300’s is like a sock so if you remove the old one you can have a seamstress sew the new ones.

Try going to solen up in Canada. They have excellent speaker cloth there.

[c-jman]

Thanks. Just checked out Solan, they only have white or dark colors. Closest I have found is beige through SpeakerWorks or ivory from Simply Speakers. Both have material wide enough to wrap around the speakers.

[whnay1]

I am getting older and a little handicapped and want to sell my SRS's. Here is the description:

UPGRADES:

I have had the SRS Electronic Crossover rebuilt by CJ using Cardas Internal Wiring and Cardas RCA Jacks. The best part is using Teflon caps on the Hi Pass IO. The AC Power cord has also been upgraded to Cardas.

On the Mid Range Towers I have removed all original caps replacing them with Metalized Polypropylene Caps bypassed by CJD Teflon Caps. The internal wiring of them is also Cardas. I move the Banana Jacks to the back of the cabinet making it far easier to change wires. The chokes are all expensive Litz wire chokes.

The woofer towers are original and the cones and surrounds are just fine.

The cabinets are in descent shape but a little stain (MINWAX Dark Walnut Special) will make them look almost new.

The original Dynaudio D28 A/F Tweeters went bad and new ones are impossible to find so I replaced them with Aurum Cantus Ribbon Tweeters. They are simply SUPERB!

These upgrades are substantial in parts and labor but modernize the SRS.

The Midrange Towers still use the original Focal 7N501, 7" Midrange Driver, the Aurum Cantus Ribbon Tweeter, and a unique Fostex Ribbon Super Tweeter. They cover from about 80hz to 35khz. Real fast and a super image.

The bass towers are nice and tall exceeding 60" high and they used cinder blocks inside for inert blocking and bracing! They used two custom 10" drivers tuned in a transmission line that terminates into a port for each. They are so well tuned. They handle from 20-80hz!

SOUND:

The bass on this system is unmatched for its speed and air into the low 20's. Gordon Holt, of Absolute Sound and Stereophile, reviewed them and said it was the fastest, tightest deep bass he ever heard and they were the only cone woofers that would then match with the Quad Electrostats. I concur. There are many great subwoofers today, and not one of them can match the speed and accuracy of the SRS woofers.

As for the Midrange and up these SRS speakers have excellent inner detail and a focused soundstage.

Please feel free to ask any questions you may have about these great, classic speakers.

PayPal only and Buyer needs to pickup in 22032 or pay shipping and packing costs.

[admin]

I would recommend making a posting in the Classifieds section of the site: https://www.conradjohnsonowners.com/vie ... f5597054e9

I would probably recommend putting a rough asking price as that will help attract potential buyers and not waste your time for unreasonably low offers.

Definitely a very interesting speaker for sure.