Spire vs Montis Ohm rating?

[snyderkv]

MLO,

Being that the Montis replaced the Spire but is essentially the same dimensions, how can the Spire be rated at .8 Ohms and the Montis .52 or is this a typo?

I ask because I have a NAD M25 setup and the .5 Ohms is close to its limit according to the manufacture. I was going to buy the Ethos due to the lower impedance, but see that the Spire is the same.

Can someone confirm?

 

[MPS]

I don't know if those values are correct but since each model has different crossover electronics and possibly a different step-up transformer, also their impedance will be different.

 

[dmusoke]

I believe its more due to the manufacturing tolerances than intentionally different xover design. A case in point for my Spires is how both speakers with identical bill-of-materials but have different times when they shutoff when there's no audio signal. One shutoff first then about 1-2 minutes later, the other one shuts off. Recall, these are identilcal speakers with identical BOMs but their behaviours are different.

I'm confident if ML sent the reviewer more sets of Montis speakers, the 20KHz impedance reading could be anywhere from 0 to 1 ohms and never the same 0.52 ohms. I believe the value given by ML was an average over many pre-production samples.

 

[snyderkv]

I believe its more due to the manufacturing tolerances than intentionally different xover design. A case in point for my Spires is how both speakers with identical bill-of-materials but have different times when they shutoff when there's no audio signal. One shutoff first then about 1-2 minutes later, the other one shuts off. Recall, these are identilcal speakers with identical BOMs but their behaviours are different.

I'm confident if ML sent the reviewer more sets of Montis speakers, the 20KHz impedance reading could be anywhere from 0 to 1 ohms and never the same 0.52 ohms. I believe the value given by ML was an average over many pre-production samples.

Gotcha, thanks guys, just one more question so I don't have to open another thread, how often does this speaker see 20khz when playing an action movie at moderate listening levels? I'm assuming it's just spikes like during gunshots or glass breaking or does it have more to do with volume level?

I just purchased some Spires so I guess I'll have to test it out and see if the amp shuts off before downgrading to the smaller Ethos.

 

[twich54]

snyder, first off don't get nervous about the extreme ohm rating @ 20,000hz, can you name but one discernable piece of musical content at that level that you have EVER heard........I'll answer that for you...no !

Now the fall off in resistance as content approaches the upper octaves is of concern for less than capable amplifiers, remember our speakers present a challenging capacitive load that can cause an amp to become unstable in the areas where we can hear and there is musical content.

 

[snyderkv]

snyder, first off don't get nervous about the extreme ohm rating @ 20,000hz, can you name but one discernable piece of musical content at that level that you have EVER heard........I'll answer that for you...no !

Now the fall off in resistance as content approaches the upper octaves is of concern for less than capable amplifiers, remember our speakers present a challenging capacitive load that can cause an amp to become unstable in the areas where we can hear and there is musical content.

Thanks twich, you mention music exclusively but I watch just as many movies. I'll assume the same holds true

Thanks again

 

[dmusoke]

HQ Music formats sampled at 96KHz and 192KHz via SACD, BD or DVDA is where you'll ever get to meet the harmonics at 20KHz and beyond and at amplitudes much lower than the ones you can actually hear. Movies not so much as the emphasis is on dialog and low frequency special effects.

I recently tested the prowess of my Sunfire 400W x 7 amplifier and fed it an slowly changing frequency sweep from 10Hz to 20KHz over a 30 second period. No problems at all but i saw the AC mains current into the amp increasing to 13A. This amp is fed from a 15A outlet so i decided to quit the test for fear i will trip the 15A fuse in my apartment . Spires are just fine, in fact i went on ahead and performed an audio calibration of my system using ARC from my Anthem D2v and no issues at all.

 

[snyderkv]

Thanks for the input dmusoke.