Continued from this page.

If you landed here directly, please use the link above to get to the first page of this review of the Altec Lansing Valencia 846b.

To quickly summarize where I’m at – I bought a pair of Altec Lansing Valencia 846b in fairly decent shape. Drivers are original, with magnets recharged by Great Plains Audio. I have the original 846b crossovers, but they’re pretty ancient and I haven’t used them. The speakers came to me with a new set of Great Plains Audio Altec Model 19 crossovers, which I’ve used with the speakers exclusively to date.

Right now my attention is focused on two things:

  • Improving the top end / high-frequency performance of the Valencias
  • Improving the crossover

Aperion Audio Dual Firing AMT Ribbon Super Tweeters

I contacted Aperion Audio’s Collin Lybarger to see if he’d be willing to send me a pair of their super tweeters to try with this project and with my main speakers, the Piega C40. He kindly sent me 3 different models of their super tweeters. I plan to publish reviews of each of the three different models, but for now, if you need more information, please visit the Aperion Audio website directly using these links:

The Dual AMT Super Tweeter is designed to be used with any speaker with a sensitivity in the range of 87-96 dB. The spec on the Valencia 846b is 97.5db, but with the GPA crossover, I believe it’s probably one or two dB below the rated spec, so the 96dB upper end of the AMT is within range, just.

Aperion Audio Dual AMT ribbon super tweeter review


Aperion Audio Dual AMT ribbon super tweeter review


Aperion Audio Dual AMT ribbon super tweeter review

These units are extremely well built and well designed. They function stand-alone without the need for a crossover or capacitor, which is built into the unit. I plan on a full review so I won’t get into much detail here, but I will of course talk about what they do for the Valencias.

The Aperion Audio Planar Ribbon Super Tweeter can reach up to 33 kHz, and there are crossover point settings for 8K, 10K, 12K, 14K, 16K (& off) and 5 output attenuation options: 0dB, -1dB, -2dB, -3dB, -4dB, -5dB.

aperion audio ribbon AMT super tweeters

Aperion Audio AMT Super Tweeters Spec Sheet


Collin at Aperion was kind enough to send along a pair of silver speaker cables, which are excellent cables in their own right. In fact, here’s a tip – if you use monoblock amps with your speakers, or just need short runs within 6′, take a look at these on the Aperion website I see no valid reason why these couldn’t replace far more expensive speaker cables in your system. Although there are no specs on the website, they do look extremely well built and sound just fine with the AMTs. If I have time, I’ll try to throw these up against some Cardas wiring that I have and see how they perform as full-range speaker cables.

Anyway, connection of the AMTs to any speaker system is easy, just parallel up on the main speaker terminals and sit the unit atop your main speakers.

So I started out with the AMTs perched atop the Valencia aligned with the front of the speaker cabinet. Given that the sensitivity of my speaker system is somewhere around the upper limit of the maximum operating range of the AMTs, I started out with the crossover settings at 10khz and the ‘treble adjustment’ set at 0db. I kicked off the initial trials with vinyl, resorting to my trusty evaluation recording, John McLaughlin, Paco de Lucia and Al Di Meola ‘Friday Night In San Francisco’. My copy is the 100% analog 180g vinyl pressing from Impex Records and mastered by Bernie Grundman and Bob Donnelly from the original analog master tapes. When I play this recording on the main system with the Piega C40 speakers [Piega C40 reviewed here], there’s plenty of air in the recording, excellent retrieval of ambient cues from the venue that does a great job of recreating the original space in your room, and the notes from these virtuoso players spring forth from the mix with a high level of dynamic realism, and for want of a better expression, bite and attack. On the Valencias, this recording has sounded nicely spacious, and quite life-like in a ‘you are there’ sense, but it has lacked the dynamic attack on the high end, and lacked the air and sparkle around the acoustic guitars. With the Aperion Audio AMTs, there was an instant and noticeable improvement on the top end. I could immediately hear an improved sense of resolution and detail, with notes having more attack, more presence, and more impact. What I also noticed was a sense of the stage becoming a little flatter front to back and images just a little less focused and a little more diffuse. More extended in the other two dimensions, but a little shortened in the depth perspective.

That was easily fixed with a little experimentation on positioning of the AMTs relative to the other drivers. Pushing the units back around 6 inches seemed to help with integration of the added higher frequencies, and also restored the depth of stage and increased the overal focus of the music. I’m sure this has everything to do with phase/time alignment of the AMT with the other drivers, which can only really be done in this arrangement by experimentation with physical placement. Fortunately, the Valencias are quite deep, front to back, so there’s plenty of cabinet surface area to move the AMT until things properly snap into focus.

Although pushing the drivers back, physically, in relation to the horn driver and cone woofer helped with focus and stage depth, it took slightly from the initial improvement in dynamic attack on the top end. That extra little distance added between my ears and the ribbon tweeters obviously dropped a half dB or so at the listening chair, and although the effect was small, it was noticeable. I then tried switching the crossover point to its lowest setting of 8khz. At this point, with the 0db setting on the attenuator, the AMT was outputting its maximum 96dB. That helped restore some of the high frequency energy a little, but personally I would have preferred to keep the XO setting higher, perhaps at the 10 or even 12khz level. I think what’s needed is some way to attenuate both drivers in the Valencia, to put the AMT more into the middle of its efficiency operating range. That’s something I’ll give thought to for the next step of this project, which is working out an improved crossover scheme for the Valencias.

Minor niggles aside, the AMTs make a noticeably and worthwhile improvement to the Valencia, giving the speaker more top end presence, more air and sparkle. It’s almost like you’re ‘modernizing’ the speaker, without taking anything away from its ‘classic’ presentation and charm.

I still have work to do and things to try with the Aperion Audio Dual Firing AMT Ribbon Super Tweeters, and I still have the lower models in the range to try. In fact, the middle of the range unit has more extension, up to 40khz, and is a monopole design versus the dipole design of the unit under test here. So it will be interesting to hear the differences between the two.

I’ll return to this review and add more information as I continue with the trials and tests. Next up is a complete switch from the direction I’ve been going in, with the addition of a Lyngdorf TDAi 2170 integrated amplifier with Room Perfect room correction software and programmable digital crossovers. The unit is here, I just need to find the time to get it all set up.

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June 23 2022

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