Product Review - Soundline Audio SL-3 Ribbon-Dynamic Hybrid Speakers - May, 2000

John Kotches


Design: Two-way Ribbon/Dynamic hybrid, bass reflex enclosure 

MFR:  40 Hz – 20 KHz  ± 3 dB

Crossover Frequency: 259 Hz

Crossover Slope: 12dB/Octave

Sensitivity: 88 dB/1w/1m

Recommended Amp power: 10 - 200 Watts

Dimensions (H/W/D):

Ribbon Panel: 65 3/4" / 9 1/4” / 2”

Woofer Enclosure: 20” / 9 1/4” / 20”

Overall: 65 3/4” / 9 1/4” / 20”

Weight: 65 Pounds Each

MSRP: $2,195 (Oak/Maple/Black Oak) - Sold Factory Direct Only

Options: $100  for Zebrawood finish, $50 for bi-wiring/bi-amping capability


Soundline Audio; Web


How does a new manufacturer get started in the audio business?  Typically, it's the “Brick and Mortar” (B&M) model.  With B&M, usually the manufacturer sells product through a distributor or, less frequently, directly to the retailer.   The key to this model is getting the product in the retailers' hands.  If the manufacturer can afford the cost, training the retailers on demonstrating the product to reveal its optimal use is also done.  The problem for the retailer is that some manufacturers require a substantial investment in minimum inventories for a company that has yet to build a track record.   This can be a stumbling block to getting retailers to stock and sell the product.  Once the product is in the retailer's environment, it is up to the retailer to demonstrate the product effectively.  For the consumer, this is still a mixed bag since the retailers' auditioning room has little to do with how the product will actually sound in their home, in their system.   Most quality retailers allow an in-home audition so that the customer gets a feel for how things sound in their own home. 

Another option available is for the manufacturer to go the factory-direct route.  As the Internet becomes more ingrained into our culture, it's possible to deliver information about products for a (relatively) modest investment.  But, with factory-direct sales and no retail channel presence, how does a start-up manufacturer get the word out?  Sometimes, it's the old-fashioned way – with an ad in a printed publication. Soundline Audio, whose product, the SL-3 loudspeaker, is under review here, caught my attention with such an ad.  I happened across it in the final edition of Audio, and had I not seen the ad, I wouldn't have known about the company.  This leads us to the other method for getting the word out about a new product, via magazine reviews, be they print magazines, or web-zines, like Secrets of Home Theater and High Fidelity.

Design and Construction

The SL-3s utilize a ribbon midrange/tweeter and dynamic woofer.    All of Soundline Audio's stereo pair speakers (the SL-1 through SL-5)  crossover to the mid/tweeter ribbon at 250 Hz.  Musicians, take note, everything from about middle C upwards on the piano keyboard is covered by the mid/tweeter ribbon section.  If you're counting, that's 6+ octaves for the mid/tweeter ribbon , with only 3+ octaves below 250 Hz covered by the woofer section.

The woofer is an 8" cone, made to Soundline Audio's specifications by a 3rd party manufacturer, and optimized for the bass reflex enclosure.  The enclosure houses the binding posts from the amp to the speaker on the rear of the cabinet.   The binding posts are ruggedly constructed 5-ways, which accept 1/2" spade lugs, banana plugs, or up to 10 gauge wiring through the center hole or around the post.  I didn't try pins, so I can't tell you how well they work with these binding posts.  You don't need to break out your binding post wrench, because they have nicely spaced indentations which allow you to get very solid fastening to bare wire or spade lugs using just your fingers.   The rear also has the port that supports its bass reflex design. The top of the enclosure has binding posts for the crossover's high-pass output to the mid/tweeter ribbon section (see my “Areas for Improvement” below for commentary on these binding posts).  It also has the lock nuts for screwing down the mid/tweeter ribbon panel to the woofer enclosure.

The mid/tweeter ribbon panel is perforated at the bottom in front of the woofer.  The ribbon itself is 49" in length and begins about an inch above the top of the woofer enclosure in the panel.  The mid/tweeter ribbon is built by a 3rd party manufacturer, again per Soundline Audio's specifications.  The ribbon panel (frame) is 65 3/4" high, 9 1/4" wide and a scant 2" deep.

Assembling the speaker is a pretty simple task but because of their size they're a bit unwieldy.  I used a two-wheeler to move them from my living room assembly area to my home theater (ok, the family room).   You'll need floor space, with at least 6 feet of clearance for the mid/tweeter ribbon panel.  The panel is cumbersome and weighs around 40 pounds.  A Philips head screwdriver is the only tool required from your toolbox.  Set the woofer enclosure on its side, and slide the panel into place over the woofer.  Two wood screws attach the bottom of the panel to the woofer enclosure (my sample came pre-drilled).  Two machine screws attach the center portion of the mid/tweeter ribbon panel to the top of the woofer enclosure.  Once this is done, the mid/tweeter ribbon panel is firmly secured.  Simply attach the ribbon's electrical wires to the binding posts on top of the woofer enclosure (gray to black, white to red), and you're ready for listening.

Listening to the SL-3s

My first listening impressions of the SL-3 are summed up in three words “Bright, bright, bright”.

There was a metallic sharpness to most of the treble (too much sheen on the cymbals) and sibilance so present that they were nearly unlistenable.  I started extended break-in over the next week, with the speakers playing music of various types, non-stop – except for the small periods of time that my wife demanded quiet.

I'd listen some more each night and would find them just a little less harsh, and a little more relaxed in their presentation.  About 5 days into the process, either I was accustomed to their sound, or the ribbons had enough hours of playing time on them.  Either way, I knew I was definitely enjoying their presentation, and the serious listening was about to get under way.

I listen to a variety of music – and you'll hear me referencing plenty of acoustic jazz.  I've listed some of the highlights of my listening sessions, to give you an idea of how they sounded to my ears.

One recording I've listened to again and again is John Coltrane's  "Giant Steps".  This is a classic recording of the tenor giant, and it is a great jazz recording.  Even though the recording is over 40 years old, it's an excellent example of  how good a job could be done then.  Off kicks the title track, and I'm keeping time on the cymbal with my right hand – the presentation is smooth, natural, and relaxed.   Art Taylor's ride cymbal is accurately reproduced – propelling the group through their incredibly frenzied pace.  During Coltrane's improvisation, even with the notes flying out of his instrument (at an incredible 720/minute), they were clearly delineated from the top of his horn to the “barking” produced at the bottom of his instrument.   Moving on to the beautiful “Naima”, these speakers catch all the delicacy Coltrane is coaxing from his horn.  These speakers display the contrast very well between Coltrane's hard bebop / all out swinging and the warmth he had on ballads.

For fun, I pulled out Supertramp's "Breakfast in America".   I really enjoy the title cut where you hear trombone, tuba, and clarinet – not your usual pop fare instrumentation!  During the harmonies, the line source produced a vertical illusion, as though the voices were stacked one atop the other on the left and right speakers.  Ah, the power of a line source transducer.  There's a clarinet interlude, and with poor speakers, it's difficult to tell whether the instrument is a clarinet or a soprano sax.  If you're aware of what's going on, the break from the clarion to the throat register is a dead giveaway.  On the SL-3s, there is no question it's a clarinet, with a bright tone in the altissimo register.  I also took the opportunity to turn the volume up for a moment on “Goodbye Stranger” – I could find no sense of strain from these speakers at any sane listening level.  Granted, I'm not a loud listener, but for fun, I dragged out the SPL meter, and from my 3m listening position, had the sound at over 90 dB, for just long enough to see how they managed at higher volume levels.

Switch gears, it's time for some Big Band music, from the Bob Mintzer Big Band and their "Camouflage" recording.  The opening tune “Techno-Pop” is a hard driving number starting with an explosive pop.  You get the explosive pop and Randy Brecker takes a solo on this one.  The SL-3s give a very convincing illusion that he's standing off to the right hand side.  When he attacks with extra emphasis, you get an almost palpable presence of his horn as the notes seem to hit you.  I also listened to “A Long Time Ago”, which is a ballad featuring the band leader on tenor sax.  This is another example of some extended playing that covers from the octave below to two octaves above the crossover.  At no time did I notice any breakup, just a smooth and convincing rendition of Mintzer's saxophone.  “A Long Time Ago” also has a great amount of dynamic range, with portions (like the beginning) where the band is playing at barely a whisper and the end, where the tenor soars over the band during a shout chorus.

Out comes some Samuel Barber material, “Overture to School for Scandal”. The opening bars have the triangle ringing out over the orchestra, crystal clear with the various sections of the orchestra.  The cohesiveness of the Symphony is never lost, but the detail of the various sections parts are never obscured.   In fact, some very low level detail is drawn out nicely in the quieter moments of this composition, with clarinets nicely accompanying strings.  The oboe during the lyrical midsection is reproduced with the reediness and warmth unique to the instrument.  In the final bars of the piece, the sharpness of the trumpets with the triangle are right where they are supposed to be.

What these speakers don't do, is reproduce the last low octave of music convincingly and with huge impact.  Given that they're rated down to 40 Hz, I'm not the least bit surprised at this characteristic of the speakers.   Pull out any of the Telarc recordings with the huge bass drum, and you'll understand that these speakers don't quite get the last octave, because the sheer weight of the strikes of this bass drum aren't carried across – this was the case on a recording of  “Mars” from Holst's tone poem collection “The Planets”.

Using the SL-3s in a Home Theater Environment

Like most people, I have to make do with a combined Stereo and Home Theater listening room.    I was able to integrate the SL-3s into my setup pretty well.  I wasn't able to get a seamless blend from left to center to right since I don't have all Soundlines across the front.  Equally, I was unable to get a perfectly smooth pan from front to rear on the material which contains such panning.   Most of my reviewing was done in a two-channel context, but I managed to squeeze in some Home Theater listening as well. 

I think many Home Theater reviewers use The Eagles' "Hell Freezes Over" DTS DVD as a reference recording to check out the ability of their system to reproduce multi-channel music.  During the opening of “Hotel California”, I was duly impressed – the clarity of the plucked guitar strings off of Don Felder's acoustic guitar was just a little bit better than I'm accustomed too.  Background vocals were also a tad bit clearer.  Just how many guitars did they use on this track, 100?

I am a big fan of DTS-encoded music CDs, and found myself pulling just about everything out of my arsenal.  My most recent pick-up, The Police's "Every Breath You Take - The Classics" was used as well.  I use the track “Every Little Thing She Does is Magic”, because it's got a bunch of instruments coming at you from every direction.  This tune is supposed to be a lot of fun, and the SL-3s definitely help project that feeling.  Stewart Copeland does some superb work on this, getting many interesting timbres from the cymbals in his drum kit.

As far as movie soundtrack reproduction goes, these speakers do a fine job of reproducing music and dialogue from the sides of the mains.  They were also capable of reproducing sharp, hard attacks and explosions with (what I think is) convincing realism. 

Areas for Improvement in Construction

These speakers are production line proofs - they were used to verify that Soundline Audio's production processes will work.  I found several areas for improvement in these proofs, so I discussed these with Greg Godfrey and Bob Jantz at Soundline Audio via e-mail. 

Included here are my suggestions, and I'm posting their replies to these areas verbatim as they relate to changes from the production proofs.

My suggestion: The included speaker spikes have very short tips, making it difficult to decouple with the floor on thicker carpets.   The spikes also don't allow for tipping the speaker back slightly as recommended in the assembly instructions.  They're top heavy and have a tendency to tip towards the mid/tweeter ribbon during assembly and when moving around for placement.

Soundline's answer: Currently, production models utilize 4 - 3/8" diameter spike feet which are much longer to accommodate a greater tilt angle if so desired.  This longer spike also does a great job of punching through even the thickest of carpet so as to firmly anchor the unit to the foundation.  These spikes are placed closer to the edges of the enclosure and do a great job of increasing stability. As an option, we also offer outrigger feet for the SL3 and SL2 models.  (A order currently in process for a customer in Asia is getting these feet.)  They are aluminum (1/2" x 1" bar stock) and powder coated in black with spikes at the extremeties.

My suggestion: The midrange/tweeter wires are stripped and bare.  Repeatedly connecting and disconnecting the wires results in fraying, with bits of copper strands separating from the cable.  Binding posts used to attach the ribbon to the woofer enclosure have an unusual 1" spacing.

Soundline's answer: The connection from the ribbon to the binding posts on the top of the woofer enclosure now utilizes gold plated binding posts (3/4" spacing), and the leads from the ribbon are terminated with gold plated spade lugs. This offers the greatest amount of surface contact area and a solid connection.

My suggestion: No bi-wiring or bi-amping capability seems possible in the speakers supplied for review.  It looks like the ribbon connection takes its feed directly from the crossover.

Soundline's answer: As an option, if the customer desires it, we can accommodate requests for bi-wiring and/or bi-amping.  This is an option and runs an additional $50.  Bi-wiring would add another set of binding posts to the rear of the speaker so the signal would run through the high-pass to the ribbon.

All my suggested areas for improvement appear to have been addressed, but only a true production line speaker will bear this out.


These are good speakers, with a relaxed, natural presentation, and with excellent retrieval of detail from your sources.   What they don't give you is that last low octave or so (from about 38 Hz or so down to ~20 Hz).  If you have a good subwoofer that can match the clarity of the rest of the range, then you've got a ticket to some really nice sounds, reproduced full range.  In comparison with other speakers within its price range, they represent a good value.  I'd be interested to hear what an entire Home Theater from Soundline Audio would sound like.

- John Kotches -


© Copyright 2000 Secrets of Home Theater & High Fidelity
Return to Table of Contents for this Issue.

Our Vault pages may have some display quirks. Let us know if we need to take a look at this page or fix a bug.
Connect with us
  • Instagram
  • Google+
  • YouTube
  • LinkedIn
  • Pinterest
Secrets "Cave"