Dennis Had Inspire Amps

[x3workshop]

All this talk about power output has me thinking it's time to hook mine up to the scope. When I get home in a couple of weeks I'll do just that. For the record, mine has the larger opts. I'd be surprised if I got 10 watts out of it.

[x3workshop]

Originally Posted by Bombadil

I'm referring to bench tests of Tekton's speakers. For example in this Stereophile bench tests, a Tekton Enzo XL, spec'ed at 96.5dB, was measured to be just 90.6dB.
https://www.stereophile.com/content/...r-measurements

Same has been true in other bench tests of Tekton speakers, consistently measuring at 5.5 to 6.0 dB under the specs that Tekton claims.

No one polices loudspeaker specs. Manufacturers can claim pretty much whatever they want to. Tekton uses an Eminence B102 woofer/midrange in several of their speakers. Eminence specs this driver at 92dB. But when Tekton puts it into a speaker, they still spec the speaker at 97 to 98dB. Zu does the same thing, using the exact same driver.

Correct me if I'm wrong, but efficiency is also directly correlated to cabinet design.

[Bombadil]

Originally Posted by x3workshop

Correct me if I'm wrong, but efficiency is also directly correlated to cabinet design.

Yes, it is. Usually in the sense of a small cabinet lowering the maximum efficiency of a driver.

I'm not going to profess to being a speaker design, I'm a statistician. I collect facts. I haven't yet come across an independent measurement of these modern, high efficiency cone driver speakers which actually meet their claimed specifications. I certainly have an open mind on this, I have nothing against any of these manufacturers. If I find a bench test which backs their claims, I will certainly make note of it.

Klipsch spec'ed their REF-83 at 100dB. It measured at 94.
DeVore Gibbon 88 spec'ed at 90.5dB, measured at 87.2

Whereas a B&W 802 Diamond was spec'ed at 90dB and measured dead on at 90.

And the Paradigm Persona 3F was spec'ed at 89 and measured at 89.5.

[Wgarcia]

Whatever the wattage of my HO might be it has plenty of oomph (official audiophile term) at the levels I need and beyond. For the record: Since I've had the HO around (few months) I've been trying different tubes and the best sound for my taste seems to be the Gold Lion KT88s (supplied originally), a "reissued" Tung Sol 6SN7GTB, and a 274B. The Tung Sol is a sweet tube and looks appropriately retro which is very important…very.

[Rosco65]

Originally Posted by x3workshop

Correct me if I'm wrong, but efficiency is also directly correlated to cabinet design.

I'm not going to say you're wrong, but you're not strictly right. An increase in speaker efficiency due to cabinet design is usually bandwidth-limited, tending to increase efficiency from the midbass down. Examples include:

1. Open Baffle - a larger/wider baffle will allow for more efficient bass reproduction. Similarly, a wider baffle on most speakers will lower the baffle step frequency and improve midbass response.

2. Bass Reflex - the port tuning will usually increase bass and midbass response, increasing efficiency in the midbass region.

3. Horn - Horns can increase efficiency over a broader range but still need multiple drivers to achieve a full-bandwidth increase in efficiency. A rear-loaded bass horn will increase bass efficiency while doing little for the midrange and above. Front-loaded horns will also increase the lower frequency range of the driver while having a lesser effect on the upper frequencies.

Putting aside horns for the moment it is reasonably safe to say that a cabinet's contribution to any increase in speaker efficiency tends to be from the lower midrange (~500hz) and down. It is pretty easy to get high efficiency above that frequency from the driver alone, but bringing the bass up to match it is what takes heroics with the cabinet. A great example are the Omega full range drivers. The Alnico driver is rated at 95dB and the RS5 at 94.5dB (oddly specific). One is a 6.5" driver and the other is a 4" driver, rated for similar frequency response and efficiency. However, the 6.5" driver starts falling off below 200hz while the 4" driver starts falling off below 500hz. Everything the manufacturer does is support the lower frequencies to match the midrange efficiency.

[Musica Amantem]

All interesting arguments. At the end of the day, what would be easier from a stand point of improving "oomph" for classical orchestral representation: a more powerful amp or higher efficiency speakers, OTBE? This is for a near-field setup, of course. On that topic, what are the SQ tradeoffs with much increased efficiency speakers? Difficult questions, I know, but without the benefit of trial-and-error, I may have to resort to other people's opinions.

[Rosco65]

Originally Posted by Musica Amantem

All interesting arguments. At the end of the day, what would be easier from a stand point of improving "oomph" for classical orchestral representation: a more powerful amp or higher efficiency speakers, OTBE? This is for a near-field setup, of course. On that topic, what are the SQ tradeoffs with much increased efficiency speakers? Difficult questions, I know, but without the benefit of trial-and-error, I may have to resort to other people's opinions.

In your case I think a valid approach would be to keep your current speakers and amp, limit the low frequencies to the main speakers, and add active bass reinforcement below 100hz. The main driver in your Tektons will never be a 15" bass driver so you are fighting physics at the moment. If I were in your shoes, I would add 2-4 subwoofers to give foundation and impact to your current speakers.

While my Omega speakers get loud and proud, they lack the visceral midbass impact that only comes with being able to move more air. I address this in a couple of ways: by adding active bass support in the form of stereo servo subwoofers, and by adding "helper" drivers to my Omega speakers. In the case of the RS5-based speakers, I chose one of Louis "1.5 HO" models that doubles up the driver below 500hz. For my Super Alnico Monitors, I am using an Altec 414-8C as a helper midbass driver, driven off a separate amp. The SAM runs full range.

[Musica Amantem]

Originally Posted by Rosco65

In your case I think a valid approach would be to keep your current speakers and amp, limit the low frequencies to the main speakers, and add active bass reinforcement below 100hz.

I have been doing that for months now. It helps, but is not a definitive solution. It works wonders for my jazz and acoustic selections, though.

The main driver in your Tektons will never be a 15" bass driver so you are fighting physics at the moment. If I were in your shoes, I would add 2-4 subwoofers to give foundation and impact to your current speakers.

Granted, my SUB is a modest 160 watt Velodyne, low-level crossed at 100 Hz. So, maybe this is not enough ...

While my Omega speakers get loud and proud, they lack the visceral midbass impact that only comes with being able to move more air. I address this in a couple of ways: by adding active bass support in the form of stereo servo subwoofers, and by adding "helper" drivers to my Omega speakers. In the case of the RS5-based speakers, I chose one of Louis "1.5 HO" models that doubles up the driver below 500hz. For my Super Alnico Monitors, I am using an Altec 414-8C as a helper midbass driver, driven off a separate amp. The SAM runs full range.

Although I'm familiar with the servo-SUB term, I'm not sure I understand its underpinnings (what is the net value-added of the concept relative to the traditional setup)

Thanks for your interesting suggestions, which open up yet another perspective in my quest. I'm all for preserving the magic of the Inspire units while boosting-up "oomph"

[Rosco65]

Originally Posted by Musica Amantem

Although I'm familiar with the servo-SUB term, I'm not sure I understand its underpinnings (what is the net value-added of the concept relative to the traditional setup)

Thanks for your interesting suggestions, which open up yet another perspective in my quest. I'm all for preserving the magic of the Inspire units while boosting-up "oomph"

In my case I use Rythmik Audio servo subs. This arrangement allows the use of subwoofer drivers (4 x 8" in my case) with much light cones. Normally, the lightweight cones would offer deep bass, but the servo amp controls the cone motion. The result is a "fast" (i.e., responsive) bass system that can not only provide the same apparent speed as lightweight main drivers (such as in your Tektons and my Omegas) but also cross over higher to help fill in the midbass. I can run my Omega Super Alnico Monitors crossed over to stereo Rythmik subwoofers as high as 200hz.

[timeout59]

I'm using a pair of Vandersteen 2Wq subs. Each sub has three 8" drivers and a 300 watt amp. "The three eight inch drivers equal the cone area of a fourteen-inch woofer, but with much higher motor-to-cone-area ratio. The high ratio improves pitch definition and insures stable frequency and phase responses throughout and beyond the drivers ’ operating range."

They use a high pass filter between the pre-amp and amp, similar to what Musica Amantem uses with his sub or subs, to roll-off the low frequency response of the main amplifier and speakers. They connect to the speaker terminals of the main amp (the only way to connect them), which leaves the main amp in the signal path to the subs. This results in the main amp’s characteristics that are evident through the main speakers being maintained into the subs, but with the power and control of the 2Wq’s internal 300-watt amplifier.

Since the 2Wq gets a rolled off signal from the main amp's speaker terminals, the response of the 2Wq’s amplifier is contoured to restore the low frequencies to the proper level. The 2Wq’s input impedance is high enough that it has no effect on the output of the main amplifier.

I've found these subs to be the easiest to blend with the main speakers so they never call attention to themselves.