Dennis Had Inspire Amps

[BearCityUSA]

Originally Posted by Musica Amantem

BTW, I'm interested in your take on the Omega 7 full range speakers with the PSE Inspire. Now that should give you plenty of dynamic headroom reserves. How do you like the sound? I personally believe the PSE deserves the Alnico-driven monitors, but that's just me.

The Super 7 Monitors are a great sounding speaker. Very revealing. The Omega RS5 and Alnico driver do get a lot of attention but the RS7 driver is no slouch. I admit I have not heard the Alnico but I have a pair of Super 3T with the RS5 driver and I much prefer the Super 7s, all other things being equal. Though the Super 3Ts are faster they are by no means fuller in sound. I have to hypothesize it is a size thing. The larger driver can move more air. My biggest issue with my Omegas (both pair) is the limited sweet spot. I do most of my listening at my office where I have things set up so that the sweet spot which is about 2' wide is where my chair sits while I am at my computer, which is ideal for the Omegas. My second Inspire system at the house is more of a lifestyle system. Having small kids and a wife and chores and varied other interests my listening position is quite dynamic and the full range single driver speakers are very directional. I find it hard to feel like I am getting the most out of my system with Omegas in the mix there. These Epos do have a much broader listening field and do tend to fill a room. This is why I am excited by the ability to drive them with the PSE.

Originally Posted by opnly bafld

Sounds like a nice fit to me.

From Stereophile, keeping in mind your PSE has a lower output imp. compared to typical SE or PP tube amps.

"The ES 14 has a reasonably high sensitivity, 2.83V of B-weighted pink noise raising an estimated 87dB/W/m. Coupled with this highish sensitivity, it is very easy to drive, as shown by the plots of impedance magnitude and phase (figs.1 and 2). It drops below 8 ohms only in the very top octave, and then to just 7.2 ohms. I would have said that this combination of sensitivity and easy impedance characteristic would make the ES 14 a prime candidate for being driven by a classic tube amplifier. Note, however, the large swing in impedance value, particularly in the bass and upper midrange. This will mean that the speaker's sound will become exaggerated in these frequency regions when used with a tube amplifier with a high output impedance."

This is very interesting. I can attest to the exaggerated lower frequencies. Not distracting but sometimes they do sound a bit pronounced at the low end, though it may be just what I am used to listening to the Omega Super 7s. I wonder if the 2.2uf cap on the tweeter could be substituted with another which would compensate for this. More knowledgable contributors here could likely provide input here. My limited understanding of capacitor effects on AC lead me to think there may be better choices for this passive component. Any input here would be appreciated.

[Bombadil]

Those new Omega Super 3 HO monitors are quite tempting. Would pair nicely even with my older Inspire SE EL84 amp, with its 4-5 wpc output. Perhaps I should sell off a couple of pieces of gear and pick up a pair.

[Rosco65]

Originally Posted by Bombadil

Those new Omega Super 3 HO monitors are quite tempting. Would pair nicely even with my older Inspire SE EL84 amp, with its 4-5 wpc output. Perhaps I should sell off a couple of pieces of gear and pick up a pair.

That's my problem: I have more equipment than I can listen to and more than I should have in storage. Unfortunately, I almost always regret selling equipment as the direction of my system changes.

There are a lot of guys using triode wired EL84's with Omega speakers. In fact, Decware seems to be the unofficial default amp for Omega's (years ago it was Red Wine Audio. Funny how alliances change).

[Musica Amantem]

Originally Posted by Bombadil

Those new Omega Super 3 HO monitors are quite tempting. Would pair nicely even with my older Inspire SE EL84 amp, with its 4-5 wpc output. Perhaps I should sell off a couple of pieces of gear and pick up a pair.

These speakers seem nice indeed. Just beware the apples to apples nominal sensitivity at 8 Ohms impedance is 96 dB, not 97.5 dB, which is at 6 Ohms impedance. This implies a 50% higher power requirement, other things being equal, for the same SPL at 8 Ohm impedance.

[Rosco65]

Originally Posted by Musica Amantem

These speakers seem nice indeed. Just beware the apples to apples nominal sensitivity at 8 Ohms impedance is 96 dB, not 97.5 dB, which is at 6 Ohms impedance. This implies a 50% higher power requirement, other things being equal, for the same SPL at 8 Ohm impedance.

I'm not sure that that is the case with these particular speakers. Louis lists his single-driver speaker at 94.5 dB. Adding an additional driver will add 3 dB to 97.5, regardless of the impedance. That being said, calling is a 6 ohm speaker is little different than call it an 8 ohm speaker. The single driver speaker spends most of its frequency range well above 8 ohms in both the bass and treble.

In the case of the 1.5 way speaker, the second driver is filtered in below 500hz. That means that from 500hz up the speaker behaves as a single driver speaker, with impedance above 8 ohms. Below 500hz, both drivers are in parallel, but their impedance is rising as well. We can reasonably say that this speaker exhibits a 6 ohm impedance in the 100-200 hz region. More importantly, this is a smooth impedance curve, especially compared with a lot of commercial "4 ohm" speakers".

Now the question still remains if this is a real 97.5 dB speaker. I can't answer that without measuring it. The single driver Omega is touted as a 94.5 dB speaker. It certainly could be from 500hz to 15khz, but is likely more like 91 to 92 dB in the mid bass. The second driver adds 3-4dB efficiency below 500hz. Under those terms, I would be willing to call it a true 96 dB speaker in the band of 100hz-15khz. Given the tendency for manufacturers to overstate efficiency, I will grant Louis the right to claim 97.5 dB.

We should also note that Steve Deckert optimizes his output transformers for 6 ohm speakers, feeling that most 8 ohm speakers are closer to 6 ohms over much of their range. Dennis' amps are also capable of near full power into 2 ohms, which implies being optimized for the average speaker. Assuming the Omega 1.5HO is a true 6 ohm speaker, it would appear to the optimal for most efficiently getting the most power out of these amps.

[Musica Amantem]

Originally Posted by Rosco65

I'm not sure that that is the case with these particular speakers. Louis lists his single-driver speaker at 94.5 dB. Adding an additional driver will add 3 dB to 97.5, regardless of the impedance. That being said, calling is a 6 ohm speaker is little different than call it an 8 ohm speaker. The single driver speaker spends most of its frequency range well above 8 ohms in both the bass and treble.

In the case of the 1.5 way speaker, the second driver is filtered in below 500hz. That means that from 500hz up the speaker behaves as a single driver speaker, with impedance above 8 ohms. Below 500hz, both drivers are in parallel, but their impedance is rising as well. We can reasonably say that this speaker exhibits a 6 ohm impedance in the 100-200 hz region. More importantly, this is a smooth impedance curve, especially compared with a lot of commercial "4 ohm" speakers".

Now the question still remains if this is a real 97.5 dB speaker. I can't answer that without measuring it. The single driver Omega is touted as a 94.5 dB speaker. It certainly could be from 500hz to 15khz, but is likely more like 91 to 92 dB in the mid bass. The second driver adds 3-4dB efficiency below 500hz. Under those terms, I would be willing to call it a true 96 dB speaker in the band of 100hz-15khz. Given the tendency for manufacturers to overstate efficiency, I will grant Louis the right to claim 97.5 dB.

We should also note that Steve Deckert optimizes his output transformers for 6 ohm speakers, feeling that most 8 ohm speakers are closer to 6 ohms over much of their range. Dennis' amps are also capable of near full power into 2 ohms, which implies being optimized for the average speaker. Assuming the Omega 1.5HO is a true 6 ohm speaker, it would appear to the optimal for most efficiently getting the most power out of these amps.

Quote from Gene DellaSala, contributor to Audioholics:

Comparing the Sensitivity of Speakers with Different Impedances

"If the amplifier is set to 2.83V, the 4 ohm speaker will draw 2 watts of power from the amplifier while an 8 ohm speaker draws 1 watt. (Power = Voltage2/resistance. So, 2.832 = 8. 8/8ohms = 1 watt.) This potentially gives the 4 ohm speaker a +3dB SPL advantage over the 8 ohm speaker for a given input level. This seems to be unfair. Therefore, some engineers and reviewers adjust the input voltage so that it equates to 1 watt at the impedance of the input frequency (or band of frequencies) of the speaker under test."

If we assume a linear relationship, quoting a 97.6 dB sensitivity at 6 Ohms is misleading by 1.5 dB if we take as reference the standard nominal 8 Ohm impedance speaker. If we are considering a low-power amp, I'd take the higher sensitivity at the same Impedance reference anytime, OTBE. Its unfair to quote a 6 Ohm sensitivity rating as a standard 8-Ohm comparable reference, which is not. The same sensitivity rating at 6 Ohm will yield an SPL deficit relative to that sensitivity rate at 8 Ohms for any given fixed amp power.

My point is simply to beware these numbers may be critical for someone at the low limit of power amplification. Regardless of the crossover on the second driver, the cited 97.5 dB sensitivity is presumably measured at 1 meter, so the net SPL result already contemplates the speaker's topology/configuration.

I'm not saying these speakers are not feasible options for low power amps, but are not standard 97.5 dB sensitive.

http://www.audioholics.com/loudspeak...er-sensitivity

[Bombadil]

There is also the issue of how many speaker companies inflate their sensitivity specifications. Stereophile always measures sensitivity when they review a speaker. It is rare when a speaker meets specifications. In the case of Zu speakers, their measurements tend to come in at 5 to 6dB lower than Zu's specs. Speakers being sold as 96dB, measured at 90db. That is an immense difference, as to reach a specific volume level would require 4X the power with a 90dB speaker.

[Bombadil]

The obvious comparison of Omega monitors in this price range is the new Super 3 HO vs the Compact Alnico Monitor. Only $200 price difference. Sensitivity at 8 ohms is 95dB vs 96dB, so not really a deciding factor IMO. Would be great to hear them side by side.

Right now my little Inspire SE EL84 amp is connected to 87dB speakers, with an active small subwoofer crossed over at 100Hz. This combo works pretty well. The SE EL84 completely falls apart when it attempts to run full range, it's output transformers begin to roll off at under 80Hz. Dennis used fairly inexpensive transformers on these Magnavox-type amps.

[FloridaBoy]

Originally Posted by Bombadil

Those new Omega Super 3 HO monitors are quite tempting. Would pair nicely even with my older Inspire SE EL84 amp, with its 4-5 wpc output. Perhaps I should sell off a couple of pieces of gear and pick up a pair.

Originally Posted by Rosco65

That's my problem: I have more equipment than I can listen to and more than I should have in storage. Unfortunately, I almost always regret selling equipment as the direction of my system changes.

There are a lot of guys using triode wired EL84's with Omega speakers. In fact, Decware seems to be the unofficial default amp for Omega's (years ago it was Red Wine Audio. Funny how alliances change).

Bombadil,

If you don't have a pair of efficient speakers the Omegas would be a good choice. I was looking at the Compact Alnico Monitors but the higher efficiency of the Omega Super 3 HO may be better with low power amps. I'm happy with my Klipsch Heresy III's but the Omegas are still interesting.


Rosco, I think most of us are guilty of the 'too much gear' & the 'there is something better' disease too. Maybe it's not better, just different.

[Rosco65]

Originally Posted by Bombadil

The obvious comparison of Omega monitors in this price range is the new Super 3 HO vs the Compact Alnico Monitor. Only $200 price difference. Sensitivity at 8 ohms is 95dB vs 96dB, so not really a deciding factor IMO. Would be great to hear them side by side.

Right now my little Inspire SE EL84 amp is connected to 87dB speakers, with an active small subwoofer crossed over at 100Hz. This combo works pretty well. The SE EL84 completely falls apart when it attempts to run full range, it's output transformers begin to roll off at under 80Hz. Dennis used fairly inexpensive transformers on these Magnavox-type amps.

That is a reasonable statement when talking about the Level 1 finishes. Both speakers have the same size cabinet, about the same driver area, and simmilar efficiencies. However, each has its place:

1. The CAM is designed for near wall positioning with a wide baffle. This will help reinforce the midbass.

2. The Super 3HO is designed as a more conventional monitor and is proportioned to be placed further into the room.

3. The CAM naturally has more bass than the smaller driver of the Super 3 series. However, the .5 driver below 500hz compensates both the the reduced LF output and for baffle step.

4. The alnico driver has superior midrange quality but the RS5 driver has a better top end and is faster.

I own speakers based on the alnico drivers and the RS5 drivers, both a wide baffle Super 3 and narrow baffle Super 3U. IMHO the RS5-based speakers really need some midbass help. The single alnico speakers are fuller but still benefit from proximity to room boundaries.

In either case, we're talking about the equivalent surface area of a single 6.5" driver. It will only move so much air and one tradeoff to get high efficiency from a small driver is to sacrifice bass. Actively crossing over with one or two subwoofers is a valid solution.