First of all an excuse for my bad english.. In my opinion the SP-3500 are one of the best speakers to use with single ended tube amplifiers. The sensitivity of 96dB/w/m is absolutely realistic, not only claimed. This sensitivity is necessary for small SET-amps, using 2A3, 300B etc. The frequency range is broad, compared to suitable full-rangers.
The midrange is sweet, vocals are engaging and intimate, maybe forward, the bass is dry, realistic and precise, the highs undemonstrative and natural.
Sansui wrote in it's product brochure: "Perhaps the most timely speaker system ever introduced...", and that's correct. The presentation and depth of the soundstage of this speakers is so very "3D", the imaging so very precise, and the size of objects so natural, that you can't believe you are listening to a 6-driver-speaker. The multidirectional arrangement of the two mylar-alnico-horn-tweeters and the two (I guess silk-) ferite-cone-midrange-drivers offers (in my opinion) an even better realism or naturalism, than fullrangers can achieve. The upper-midrange-horn is using an accoustic lens for wide dissipation and a titanium-driver and is fitted in the center of the multi-directional drivers assembly. The bass is equipped with a mechanical low-pass and is directly connected to the amplifier, without passing through the crossover, like a full ranger.
I had the chance to compare the SP-3500 speaker directly (A-B-A-B...) to the highly regarded JBL-4430-studio monitor, using a GM-70 DHT-SET tube amplifier, and prefered the Sansui SP-3500 for it's more natural presentation, and it's 3dB higher sensitivity, even if the 15" bass and bigger cabinet of the JBL was reaching a little bit lower, than the 14" bass and smaller cabinet of the Sansui SP-3500.
What about repair and tune-up? No major changes should be made, regarding tweeters, crossovers, cabinets, positioning of drivers! You would only destoy a unique sounding collectible. The crossovers electrolytics should be recapped with MKP-capacitors (for example Audyn Q6 or more pricely boutique caps, if you want to spend more.) The contacts of the crossover rotary switches have to be cleaned and checked for high enough contact pressure, they are the main reason for unsatisfying performance. Refoaming is neither possible nor necessary, the SP-3500 have cloth surroundings. With this changes the speakers should last forever.
Using an average solid state amplifier the qualities of this speaker will not show up and the SP-3500 may sound totally different. I made this experince with a 90s Pioneer solid state amp I was testing before selling it at ebay..

Steve a Audio Enthusiast has a bit of PT Barnum in him.

The Sansui drivers, including replacements, are Japanese, nothing is JBL. Nothing was designed by JBL.

As far as the speakers, not bad, sound a bit "larger than life' if you like that sound.

Let me first say, I read the reviews here on the SP-3500 Sansui Speakers. I worked for customer service, JBL Sound in 1974 and we would recieve the SP-3500 speakers for repair. The Cabnet design and speakers were all designed by JBL for Sansui. The replacement speakers and network deviders are all manufactured by JBL, thats the reason why the sound is so great.

Bought a pair of SP-2500X at the goodwill 10 years ago for 25 bucks paired with my little Marantz 2515B sounded, Outstanding!!! Today at Goodwill found a pair of SP-3500's 53 and change for those guess I need a Bigger Marantz.... Yeah BUY these speakers if you stumble over them cause they are BOULDERS!!!!!

These speakers are Pre-1995 by about 25 years. While on my 2nd tour in Vietnam, I went to Saigon to give an after action briefing. I was supposed to return to the field later via chopper, but the flight was scrubbed due to heavy rain. I stayed in a Vietnamese hotel that night (semi-clean sheets!) and the next day found myself near a post exchange. I was just looking around because I didn't have much money with me and sort of stumbled onto these speakers … literally. They were playing CCR and as I headed toward the music, I barely bumped a display shelf, but it was enough to knock it over, making John stop at “Over on the mountain”. A buck sergeant came at the run, looked at the mess and glared at me, but not so long as I was a captain at the time. He screamed that he had just completed the setup less than 10 minutes ago and now the stuff was worthless. I pulled out what money I had and without counting it said I'll give you this for it all. He looked around at me, laughed, took my money and left. Minutes later he returned with a receipt. Not only did I get the speakers, but also there was a QX-6500 quadraphonic receiver included! I packed them up in the original boxes, grabbed a moped and returned to the compound for pickup.

They were stored in the battalion bunker for about 4 months. I was WIA and was air lifted home. My personal affects caught up with me several months later. I was surprised all my stuff was intact as looting of personal effects boxes was normal. In my last 4 months there, I managed to pick up a set of the smaller 2500 series with 12" woofer, but had to pay regular price for them and had them shipped directly home to the USA.
Here it is nearly 40 years later and I'm still using those 4 speakers and they sound as good as ever. The 3500s are L/R front with the 2500s employed as the back L/R surrounds. I've had a variety of speakers supplementing the Sansui quartet over the years, but they have remained the foundation for both music and home theater listening for four decades. Currently, the supplementation team consists of an Infinity C360 (center), Polk Audio RTi A3 (surrounds L/R) and a Klipsch SW-450 Subwoofer. Yeah, just ask me if I’ve got base, and at both ends of the room. The 3500s pump it out up front and the Klipsch does so from the side/rear of the room. An explosion in a movie makes you feel like you lit the too short fuse. The receiver is an Onkyo TX-SR707 (recently installed) and everything seems to work well together for music or movies.
I can’t imagine audio without the 3500s. I often listen to music (jazz and old rock mostly) and use ONLY the 3500s. They and the 2500s have stood the test of time well in appearance too. With a little furniture oil rubbed in a couple times per year, they look as good as when I packed them up in Saigon. The front cutouts are like new as well. I’ve listened to many other speakers as potential replacements, but I’ve always ended up spending my money on replacing or adding to the supplementation speakers instead. These speakers have become like old friends and will likely me last for the remainder of my life. Not a bad investment for less than 10 bucks.

This is an awesome sounding retro piece of work by Sansui:) Very open and deep sound stage with great detail. I'm using them as spare speakers and lovin it. Very well built heavy and solid.

Midrange and bass response Power handling capability (100W per speaker)

High freq response (can be compensated for).

Wonderful sounding speaker with excellent midrange and bass. When I first got these massive speakers home and connected them to my Technics SA-300, I was a bit disappointed. All I could hear was midrange. Then I coaxed them a bit by turning up the bass and treble beyond their normal settings and viola! The Sansuis came to life. I realized that I had been missing the midrange entirely on my previous, German-made Heco 3 SFs (3-way). The 4-way Sansuis deliver excellent midrange making vocal passages come alive. Piano solos will sound like the piano is in your house! You'll need a sufficiently powerful receiver/amp to unleash the bass from the 14" woofers (mine is a 45 w.p.c. Pioneer SX-780). Highs on the SP-3500S seem to roll off a bit early so you'll need to boost the treble to compensate. Cosmetically, these speakers are stylish but sedate looking, like they belong with your grandma's stereo. But take off the wooden lattice (hand-carved?) speaker grills, and you will see that these babies mean business. 6 drivers per speaker arranged symetrically in the cabinet deliver a powerful sound that seems to get better at higher volume levels. To my wife's dismay, I can't stop listening to them! If you find a pair that you're thinking of purchasing, make sure that you set the attenuators on the rear of each speaker consistently before listening.

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These things are brutes, I played them very loud on a old Fisher amp for years and never hurt one of them. The mids and subs are great very clear. I've got mine about a foot off the ground and they sound wonderful. To get something new with the same sound you would pay big bucks. And can you believe i have four of these monsters.

There big and heavy and the highs are a little muffeled. But if they are put with a decent surrond system then no problem.

My parents bought a house in 1983 and there were four of these speakers in the house.(sp-3500)along with a quadraphonic 8 track and reel to reel.

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Everything about them is great. They are clearly built to last. Awesome lattice work grilles. Very heavy. These ain't no KLH's...

Old. My brother in law was in a band. From the looks of these drivers these were used as PA speakers during their practices. Such a shame...

I have a pair of SP-3500's that have obviously been through some pounding music. Most of the speakers in this 6-way speaker sound pretty terrible. The 15" woofer's surround is almost peeled off most of the way around. I know they were top of the line 30 years ago. I'm just hoping I can find replacement drivers to do them justice.

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Full smooth range and rich sound

30+ year old technology and specs

As in earlier reviews, my Sansui 3500's also came over from Vietnam in the early 70's - I too have all original paper work - I believe they were made available at Navy exchanges - the price paid back then "$84.50" - not too shabby even in 1970. The spec sheets are also impressive - my father in-law purchased an entire Sansui system, turntable (amazing machine), reel to reel (also amazing), mic, and receiver (massive tuner). I only use the speakers right now as the other components require some work. The speaker sound is very impressive - a big step forward over my old Bose 501's and 301's combination (that was a costly mistake). Very full smooth range and natural sound - similar to higher end JBL's that I have heard (and love as well). I love the wood veneers too. Mine have a very impressive wood mesh front to them (called Kumiko, made of Walnut)- can't imagine anyone putting something like that on the front of a speaker these days for under a couple grand. I run them off a smaller HK receiver and when cranked they rock. From my wife's Boccelli to my Beethoven symphonies and Jethro Tull golden oldies - these speakers can be mesmorizing. One problem I had was that the glue on the woofer surrounds broke down - I repaired that and they have performed like champs ever since. Some tech notes from the paper work: 14" woofer; 1st midrange 4" 2 cone-type; 2nd midrange 4.5" horn-type; tweeter 2" two horn-type; 100watts Max; 8ohms; 58lbs; ~25"x17"x11"; sensitivity 96dB/W; Range 25-20KHz normal listening; Crossover freq 700Hz,2,000Hz,6,500Hz; Cross directional firing. Lastly, the package I have also has a Sansui dust cloth - not sure if it came with the speakers or other component, but it is certainly a nice touch.

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