NX-Otica's and their efficiency

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david45

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NX-Otica's and their efficiency
« on: 12 Dec 2017, 03:31 pm »
Quick question for you, Danny.

I'm shopping around for a new tube amp and for some reason I had always thought that my NX-Otica speakers were 93.5 db/1W/1M but I keep reading 92db on the forum.  :scratch:

Which one is it? How efficient are they?

Danny Richie

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Re: NX-Otica's and their efficiency
« Reply #1 on: 12 Dec 2017, 03:49 pm »
I measured them at an average of 93.5db.

david45

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Re: NX-Otica's and their efficiency
« Reply #2 on: 12 Dec 2017, 06:22 pm »
Thanks for the reply, Danny.

I would consider ordering parts from you in the future to get my crossovers modded just so I can bi-amp the Otica's (Jay mentionned that option when I got the flat packs from him). In the mean time, I would want to bypass the M165s entirely and drive the MTM section with some low power SE amplifier (2a3, 421, PSE45, AD1).

Except for the fact that the mid bass woofers wouldn't be playing and that the OB subwoofers would need to cover all the way up to about 200hz, wouldn't it be equivalent to biamping in terms of the load that the SE amplifier would be seeing when driving the mtm section and how many watts it would need to be able to provide? The signal path would certainly be different though...

Do you think I could get away with just a couple watts for the mtm section considering I was able to use a 300b amplifier with the Otica's (run full range) and that I pretty much never went above 1W of continuous power on the front meter? No idea in terms of peak power though but I stay away from classical music...

What I would do is use an in-line crossover in between the pre and amp using a cap and resistor(?) of appropriate value. Speaking of which, I understand it is more complicated to do so when using an integrated amplifier (need to open it up and everything) but what about when using a power amp straight from the DAC? Is it possible to use an in-line crossover too?

Oh and the subwoofers would obviously be kept as close as possible to the speakers so that they can blend seamlessly even at 200hz (not too sure what the formula is to calculate the maximum distance allowed). Is 200hz more or less the crossover point between the m165 drivers and the mtm section?
« Last Edit: 16 Dec 2017, 03:08 pm by david45 »

Danny Richie

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Re: NX-Otica's and their efficiency
« Reply #3 on: 12 Dec 2017, 07:21 pm »
Thanks for the reply, Danny.

I would consider ordering parts from you in the future to get my crossovers modded just so I can bi-amp the Otica's (Jay mentionned that option when I got the flat packs from him). In the mean time, I would want to bypass the M165s entirely and drive the MTM section with some low power SE amplifier (2a3, 421, PSE45, AD1).

You can wire them for bi-amping real easily.

Quote
Except for the fact that the mid bass woofers wouldn't be playing and that the OB subwoofers would need to cover all the way up to about 200hz, wouldn't it be equivalent to biamping in terms the load that the SE amplifier would be seeing when driving the mtm section and how many watts it would need to be able to provide? The signal path would certainly be different though...

You could drive the lower woofers with a separate amp.

We also have just an MTM version only: http://www.audiocircle.com/index.php?topic=144907.0

Several customers have built them already.

Quote
Do you think I could get away with just a couple watts for the mtm section considering I was able to use a 300b amplifier with the Otica's (run full range) and that I pretty much never went above 1W of continuous power on the front meter? No idea in terms of peak power though but I stay away from classical music...

You might be able to get away with it if the room is not huge and you don't need high SPL levels.

Quote
What I would do is use an in-line crossover in between the pre and amp using a cap and resistor of appropriate value. Speaking of which, I understand it is more complicated to do so when using an integrated amplifier (need to open it up and everything) but what about when using a power amp straight from the DAC? Is it possible to use an in-line crossover too?

We typically use something like this. But it can be inserted into the signal path to your amp in several ways.



Quote
Oh and the subwoofers would obviously be kept as close as possible to the speakers so that they can blend seamlessly even at 200hz (not too sure what the formula is to calculate the maximum distance allowed). Is 200hz more or less the crossover point between the m165 drivers and the mtm section?

At that crossover point you'd need to set the MTM section right on top of the servo subs.

Here is a good one. http://www.audiocircle.com/index.php?topic=146187.0

mlundy57

Re: NX-Otica's and their efficiency
« Reply #4 on: 12 Dec 2017, 08:27 pm »
The Wedgies crossover around 200Hz. The NX-Otica MTM section is around 100Hz.

I have easily driven my Otica MTMs with a 5wpc EL84 based ultralinear amp. I'm not sure how that would compare output wise with a 300B SET amp.

Mike

david45

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Re: NX-Otica's and their efficiency
« Reply #5 on: 13 Dec 2017, 12:08 pm »

I have easily driven my Otica MTMs with a 5wpc EL84 based ultralinear amp.


Hey Mike! Was that with an inline crossover or full range?

david45

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Re: NX-Otica's and their efficiency
« Reply #6 on: 13 Dec 2017, 12:30 pm »

We typically use something like this. But it can be inserted into the signal path to your amp in several ways.





So it can be used even without a preamp (in-between dac and power amp)?

At that crossover point you'd need to set the MTM section right on top of the servo subs.


Ok so unless I choose to biamp with a seperate amp, I'm better off with a 80hz or 100hz inline crossover. My subs are right against the NX-Otica's and just a few inches back. I can measure the distance between the center of the lower woofer and the center of the upper mid driver using a piece of rope (?).

You don't happen to know the formula by heart by any chance?

poseidonsvoice

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Re: NX-Otica's and their efficiency
« Reply #7 on: 13 Dec 2017, 12:45 pm »
The Wedgies crossover around 200Hz. The NX-Otica MTM section is around 100Hz.

I have easily driven my Otica MTMs with a 5wpc EL84 based ultralinear amp. I'm not sure how that would compare output wise with a 300B SET amp.

Mike

Mike,

Assuming 10% THD specs for 8 watts (SET 300B) and 5 watts (EL84 Ultralinear), the difference in power is just 2dB.

A difference of 3dB and you can start hearing a “difference” in output power, but a difference of 10X (like 50 watts) is easily heard by the human ear especially when you push the speaker to play at higher SPL levels.

Best,
Anand.

Danny Richie

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Re: NX-Otica's and their efficiency
« Reply #8 on: 13 Dec 2017, 02:19 pm »
So it can be used even without a preamp (in-between dac and power amp)?

You can if you have a volume control on your DAC.

Quote
Ok so unless I choose to biamp with a seperate amp, I'm better off with a 80hz or 100hz inline crossover. My subs are right against the NX-Otica's and just a few inches back. I can measure the distance between the center of the lower woofer and the center of the upper mid driver using a piece of rope (?).

Yeah, that's about right on the filter. You'll need to know the input impedance of the amp and then this will help you figure out the cap value. http://www.pronine.ca/capimp.htm

For the distances this will help. http://www.soundoctor.com/freq.htm

mlundy57

Re: NX-Otica's and their efficiency
« Reply #9 on: 13 Dec 2017, 02:51 pm »
Hey Mike! Was that with an inline crossover or full range?

David,

Yes, that's with an inline filter.

Mike

mlundy57

Re: NX-Otica's and their efficiency
« Reply #10 on: 13 Dec 2017, 02:56 pm »
Mike,

Assuming 10% THD specs for 8 watts (SET 300B) and 5 watts (EL84 Ultralinear), the difference in power is just 2dB.

A difference of 3dB and you can start hearing a “difference” in output power, but a difference of 10X (like 50 watts) is easily heard by the human ear especially when you push the speaker to play at higher SPL levels.

Best,
Anand.

This is something I don't fully understand. If you are only using 1 or 2 watts, why would there be a difference in the sound between a 5 watt, 8 watt, or 15 watt amp (assuming the only difference between the amps is power)?

Mike

poseidonsvoice

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Re: NX-Otica's and their efficiency
« Reply #11 on: 13 Dec 2017, 04:52 pm »
This is something I don't fully understand. If you are only using 1 or 2 watts, why would there be a difference in the sound between a 5 watt, 8 watt, or 15 watt amp (assuming the only difference between the amps is power)?

Mike

I’m talking about the differences in amplifier power alone, if you put them both on the test bench.

But if you are using only 1-2 watts, correct, it doesn’t matter. You have to be sure about that though! It assumes your peak SPL levels is ALWAYS the same, etc...

Best,
Anand.

Captainhemo

Re: NX-Otica's and their efficiency
« Reply #12 on: 13 Dec 2017, 05:37 pm »
David, just a few things to consider
As Danny mentioned,  setting up your  NX-Otica networks for bi-amping  would be simple.  Buy a set of  tube connectors, make a block  to add to your existing  c/o board.   snip the pos lead going to the low pass inductor and  neg wire to the neg tube conector,   attach them  to the new tube connectors..

There is a pretty big difference between the  NX-Oticas  with the   extra  woofers compared to the  NX-Otica MTM's.  I've spent  significant time with both...... when   originally   setting up the  MTM's  I thought they were pretty equal. Spent a  few months with them while  Don  borrowed the  Oticas during the  finishing of the NX-Tremes.  When I got the Otica's back, I was  really surprised at how much  mid bass  detail  there was Those  4 extra woofers in the  80 to 200  range make a  big difference.... you've got them... I'd keep them in the loop.

If you  choose to  go for the MTm section  only you should  know the MTM's use a different   network setup, the mids are not  high passed as they are in the  full Otica's so you'd want to pull out that bundle.....you wouldn't want to  be passing your filtered signal  through the high pass bundle of caps for the NQ's.  IIRC, there is also  a different resistor value on the notch filter  on the high pass filter  for the tweeter (comparing the  full Otica to the MTm's).

If you  followed through with the  ICE Power  AS/2,  hold off doing anything until  you     give this a try.... you  may be surprised.  I'm hoping to have one in  the room here  in the next week or so for some trials... will keep you  posted

jay

ebag4

Re: NX-Otica's and their efficiency
« Reply #13 on: 13 Dec 2017, 07:22 pm »

There is a pretty big difference between the  NX-Oticas  with the   extra  woofers compared to the  NX-Otica MTM's.  I've spent  significant time with both...... when   originally   setting up the  MTM's  I thought they were pretty equal. Spent a  few months with them while  Don  borrowed the  Oticas during the  finishing of the NX-Tremes.  When I got the Otica's back, I was  really surprised at how much  mid bass  detail  there was Those  4 extra woofers in the  80 to 200  range make a  big difference.... you've got them... I'd keep them in the loop.


Darn it Jay, why did you have to say this? :wink:
I have been living with my MTMs listening blissfully secure in the knowledge that the trade off of footprint to sound was minimal.  If I try to put any more speaker (MTM to full Otica plus H Frame) in the living room I will be living alone in short order :lol:.

Time to build a new listening room  :thumb:.

Best,
Ed

david45

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Re: NX-Otica's and their efficiency
« Reply #14 on: 13 Dec 2017, 08:22 pm »
David, just a few things to consider
As Danny mentioned,  setting up your  NX-Otica networks for bi-amping  would be simple.  Buy a set of  tube connectors, make a block  to add to your existing  c/o board.   snip the pos lead going to the low pass inductor and  neg wire to the neg tube conector,   attach them  to the new tube connectors..

There is a pretty big difference between the  NX-Oticas  with the   extra  woofers compared to the  NX-Otica MTM's.  I've spent  significant time with both...... when   originally   setting up the  MTM's  I thought they were pretty equal. Spent a  few months with them while  Don  borrowed the  Oticas during the  finishing of the NX-Tremes.  When I got the Otica's back, I was  really surprised at how much  mid bass  detail  there was Those  4 extra woofers in the  80 to 200  range make a  big difference.... you've got them... I'd keep them in the loop.

If you  choose to  go for the MTm section  only you should  know the MTM's use a different   network setup, the mids are not  high passed as they are in the  full Otica's so you'd want to pull out that bundle.....you wouldn't want to  be passing your filtered signal  through the high pass bundle of caps for the NQ's.  IIRC, there is also  a different resistor value on the notch filter  on the high pass filter  for the tweeter (comparing the  full Otica to the MTm's).

If you  followed through with the  ICE Power  AS/2,  hold off doing anything until  you     give this a try.... you  may be surprised.  I'm hoping to have one in  the room here  in the next week or so for some trials... will keep you  posted

jay

Jay,

I did follow through with the ICE Power AS/2 but I was only planning on using it as my summer amp. It would replace my Virtue Audio Sensation with tube buffer. I should be getting it relatively soon.
As for the Otica's, the plan is not to get rid of them but simply to have the option of using a low power set amplifier with them. The 300b amp integrated I had in my system for 2 days only was a revelation and obviously there was no in-line crossover being used. Honestly in my system I did not feel like I needed more power than what the 210ia was able to produce. I would definitely keep the full Otica's in the loop and not acquire the mtm section only, but I was thinking that using a high pass before the tube amplifier would allow me to use an even less power (3-3.5 wpc). Call me crazy but I would actually get both a 300b amp (full range or with 80hz hi-pass) as well as a PSE45 amp (100hz hi-pass or biamp configuration) that I would rotate in my system. I feel like I need tubes in my life lol and the kt88/120 push pull integrated I have at the moment isn't up to the task.
2017 was a big year for me in terms of speakers and subs, 2018 is going to be about amplifiers and possibly a new server/streamer/dac from your buddy at mivera audio as well when it is ready (or 2019). My audio rack is quite a bit smaller than it used to be but I can easily store amplifiers in the same room and rotate them in the system depending on my mood (or temperature haha). The biamp configuration would make things more complicated for me however even though that would probably be the best option sonically speaking.

By the way I appreciate all the help I've been getting  :thumb:
« Last Edit: 16 Dec 2017, 03:21 pm by david45 »

mlundy57

Re: NX-Otica's and their efficiency
« Reply #15 on: 13 Dec 2017, 08:34 pm »
David,

You don't have to use the inline filter to roll of everything up to the crossover point of the Oticas. Just filtering out the first octave (20-40Hz) will go a long way toward reducing the power required by the amp.

Mike

Captainhemo

Re: NX-Otica's and their efficiency
« Reply #16 on: 14 Dec 2017, 12:16 am »
Darn it Jay, why did you have to say this? :wink:
I have been living with my MTMs listening blissfully secure in the knowledge that the trade off of footprint to sound was minimal.  If I try to put any more speaker (MTM to full Otica plus H Frame) in the living room I will be living alone in short order :lol:.

Time to build a new listening room  :thumb:.

Best,
Ed

Well Ed, I did say I   really  liked the  MTM's too :beer:  Unless you  go back and forth  withthem, you  won't  know  the diff so no worries. And like you said, the  space saving is really nice... that was a huge plus in my room when I was running the MTM's.   

jay

Captainhemo

Re: NX-Otica's and their efficiency
« Reply #17 on: 14 Dec 2017, 12:32 am »
Jay,

I did follow through with the ICE Power AS/2 but I was only planning as using it as my summer amp. It would replace my Virtue Audio Sensation with tube buffer. I should be getting it relatively soon.
As for the Otica's, the plan is not to get rid of them but simply to have the option of using a low power set amplifier with them. The 300b amp integrated I had in my system for 2 days only was a revelation and obviously there was no in-line crossover being used. Honestly in my system I did not feel like I needed more power than what the 210ia was able to produce. I would definitely keep the full Otica's in the loop and not acquire the mtm section only, but I was thinking that using a high pass before the tube amplifier would allow me to use an even less power (3-3.5 wpc). Call me crazy but I would actually get both a 300b amp (full range or with 80hz hi-pass) as well as a PSE45 amp (100hz hi-pass or biamp configuration) that I would rotate in my system. I feel like I need tubes in my life lol and the kt88/120 push pull integrated I have at the moment isn't up to the task.
2017 tas a big year for me in terms of speakers and subs, 2018 is going to be about amplifiers and possibly a new server/streamer/dac from your buddy at mivera audio as well when it is ready (or 2019). My audio rack is quite a bit smaller than it used to be but I can easily store amplifiers in the same room and rotate them in the system depending on my mood (or temperature haha). The biamp configuration would make things more complicated for me however even though that would probably be the best option sonically speaking.

By the way I appreciate all the help I've been getting  :thumb:

Davd,   understood   and  nothing wrong with  having lots of amp choices available   :thumb:
One thing to remember, if you are going to bi-amp, you'll need a volume/gain control on the  amp driving the   bass section of the Otica's to  be able to be able to balance with the  low powered SET amp driving the MTM section.  Once  dialed in, you'l lbe able to simply adjust the volume as normal with  pre / volume control  etc (can't reacll your setup).

As you probably saw in Mike's ICE thread, we've  been  comparing the As/2 with Don's  6C33C parallel SET mono's and  everyone who's heard    them all back to back, is surprised..  Pretty anxious to get that amp over here and  have a listen with the Otica's


David,

You don't have to use the inline filter to roll of everything up to the crossover point of the Oticas. Just filtering out the first octave (20-40Hz) will go a long way toward reducing the power required by the amp.

Mike


I was kind of thinking  the same thing at first then realized after reading it again he was wanting to take the   load off the  SET amp  :thumb:

jay

mlundy57

Re: NX-Otica's and their efficiency
« Reply #18 on: 14 Dec 2017, 12:53 am »
I’m talking about the differences in amplifier power alone, if you put them both on the test bench.

But if you are using only 1-2 watts, correct, it doesn’t matter. You have to be sure about that though! It assumes your peak SPL levels is ALWAYS the same, etc...

Best,
Anand.

Anand,

Thanks.  For me 95% of the time I'm probably not getting much past that first watt: 93dB efficient speakers, LP 8' away, average SPL high 60's to low 70's, peaks in the low to mid 90's. 

Mike

poseidonsvoice

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Re: NX-Otica's and their efficiency
« Reply #19 on: 14 Dec 2017, 01:02 am »
Anand,

Thanks.  For me 95% of the time I'm probably not getting much past that first watt: 93dB efficient speakers, LP 8' away, average SPL high 60's to low 70's, peaks in the low to mid 90's. 

Mike

Totally agree  :thumb:

For me, 95% of the time, I'm probably past 5 watts and under 10 watts: 96dB efficient speakers, LP 11-12' away, average SPL 80dB with peaks as high as 95dB. 5% of the time though, I do hit 100-105dB spl though  :icon_twisted:

Best,
Anand.