Tekton Double Impacts

Specifying speaker sensitivity based on 2.83 volts rather than 1 watt seems to be pretty much the norm these days, among manufacturers and also among reviewers who provide measurements (e.g., John Atkinson in Stereophile, and measurements performed by the National Research Council of Canada that I’ve seen published in conjunction with reviews at SoundStage.com).

I wouldn’t consider that to be deceptive, it’s just something to be aware of, especially if tube amps are to be used. Per my earlier comment, basing the spec on 2.83 volts vs. 1 watt makes no difference in the case of an 8 ohm speaker, assuming the 8 ohm spec is realistic, while resulting in a 3 db difference for a 4 ohm speaker. Part of the rationale for using 2.83 volts is presumably the fact that many high quality solid state amps can supply twice as much power into 4 ohms as into 8 ohms, which would compensate for that 3 db.

A separate issue, of course, is the accuracy of any such specs. Regarding the Enzo XL, its spec per the website is 96.5 db/1 watt/1 meter, while Stereophile measured 90.6db/2.83 volts/1 meter, with the speaker being accurately rated at 8 ohms. I’ve seen such disparities for quite a few speakers in the past, typically in the area of 2 to 6 db. In some cases the disparity is perhaps accounted for or contributed to by an unstated assumption on the part of the manufacturer of some amount of "room gain." In some cases another contributing factor may be that the manufacturer bases the spec on the speaker’s sensitivity at a specific frequency, which may be somewhat greater than its sensitivity as averaged over a broad range of frequencies (which is what JA and the NRC do). That kind of "specmanship" I **would** consider to be a bit deceptive, in contrast to the 2.83 volt/1 watt issue.

Regards,
-- Al

@mac, I wanted to note this inconsistency in how Eric specs his speakers since it has been commented on in other forums. It looks like the majority of the speaker line is 8 ohms nominal, but a few models are 4 to 6 ohms and are measured using 2.83 volts @ 1 meter and rather than 1 watt @ 1 meter/8 ohms. An important spec when choosing a tube amp.

Interesting points that Al has raised on how specs can be manipulated, (not saying that there’s any cheating going on). Regarding Stereophile’s findings with the Enzo XL, the Tekton’s seem to have resonant cabinets, even measurable on the impedance/phase curve, although these resonances should not affect performance.
I found several high-level resonant modes on all cabinet surfaces, with one at 301Hz the strongest on the sidewalls level with the bottommost tweeter and on the rear panel. Another mode, at 262Hz, was strongest on the top panel, while a mode at 414Hz dominated on the bottom half of the side panels.
All of these modes are of high Quality Factor (Q), so may measure worse than they sound. Also, the Enzo’s high sensitivity will work against these resonances being as fully excited as they are in my measurements.

Also an easy speaker to drive. That’s good news, as I am becoming more interested in trying out one of these speakers.

Mac, I see your room on the Audiokarma website. Looks like you have a whole lot of room treatment. Just curious did you come up with what needs to go where, how many etc on your own or did you have some consultation to help you figure it all out? I currently just have some owens 703 in basically random places but am interested in doing it right but don't really have a clue how to start.

Thanks for the explanations Al and lowrider. While I don't have a lot of technical knowledge regarding audio equipment, I enjoy learning about it. All this time I was focusing on sensitivity specs without giving thought to impedence. That explains why my tube amp is having a harder time driving the 4 ohm DI's than the 6 ohm Enzo's even though they're both about 98 db sensitive. I'm told the impedence curve also influences how hard a speaker is to drive? The flatter the impedence curve the easier it is to drive? Thanks for your help. While I care more about sound than specs understanding how the electronics and the speakers react to one another is very helpful in choosing the products that will work well together. Thanks again. 

Mofojo,

Steve Deckert of Decware helped me with placing the quadratic diffusers at the first reflection points on the ceiling, one side wall and on the back wall along with building floor to ceiling bass traps in each corner and hanging heavy velvet curtains on the side wall without the diffusers. We also decided to cover all of the exposed ductwork with acoustic foam. The room sounds great. Building a dedicated room was one of the best audio investments I've made. I wish I could share some specific wisdom for your room, but I pretty much followed Steve's advise. My room is in the basement with low ceilings, 7'6", so I guess the bass traps are more necessary. Placing diffusion at the first reflection points seemed to really help along with carpet and padding on the concrete floor. After that experimenting with absorption throughout the room, especially where the walls meet the ceiling would be the extent of my advise. Hope that helps.