I've run the NaO Note and the NaO II using the 2x4 and the newer 2x8 with 24/96. The only problem I had with the 2x4 was the limited output of 0.9 V RMS limiting the output of my amp to about 50 watts before the 2x4 clipped. With the 2x8 and the higher output I am hard pressed to hear a significant difference between the fully active NaO II in analog mode or dsp mode. Certainly noise and dynamic range are not issues at all.
Currently I am running this fully active off the 2x8 with very good results. With 125 watt amps the speaker will produce greater that 100dB (music) SPL at my listening position and easily handle peaks in excess of 110 db.
Currently I am running this fully active off the 2x8 with very good results. With 125 watt amps the speaker will produce greater that 100dB (music) SPL at my listening position and easily handle peaks in excess of 110 db.
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I'm trying to understand the details to do just that. I'm not facile with AXOs, I've only built relatively simple ones to date. Programming the Orion transfer function from scratch is cool, but I don't get the details well enough yet.
It certainly has not been any concern in my applications. The increased output of the 2x8 is far more of a factor.
John,
All I'm saying is that kind of noise is a show-stopper for some folks. Maybe not you or me, but some folks.
One of your NaO systems utilizing a DSP crossover vice an analog one might be a show-stopper for some folks too.
This type of noise content from DSP gadgets nowadays is not unusual. I have a variety of black boxes on my test bench that are very similar.
Cheers,
Dave.
All I'm saying is that kind of noise is a show-stopper for some folks. Maybe not you or me, but some folks.
One of your NaO systems utilizing a DSP crossover vice an analog one might be a show-stopper for some folks too.
This type of noise content from DSP gadgets nowadays is not unusual. I have a variety of black boxes on my test bench that are very similar.
Cheers,
Dave.
It is interesting to see the 2X4 being preferred on quality grounds (noise in this instance) over the 2X8. Maybe there is not much difference between these units other than convenience (I really want to go dual 2X4s and have one attached to each stereo speaker, but am concerned the 2X4 will be inferior sounding - perhaps due to inferior adc/dac conversion and maybe other issues).
Sounds like the revB does not help the specific 0.9V signal level issue John mentions here from what I have read elsewhere.
Thinking out loud, I wonder is there a benefit in having a transformer just before the minidsp (like I do on my current PLLXO to account for input losses)?
Sounds like the revB does not help the specific 0.9V signal level issue John mentions here from what I have read elsewhere.
Thinking out loud, I wonder is there a benefit in having a transformer just before the minidsp (like I do on my current PLLXO to account for input losses)?
The balanced one does output a hotter signal. But in most systems you'll need to make adapters for the Phoenix connectors. It's neither particularly hard nor particularly time-consuming.
Then the balanced one is definitely the better choice. If you don't already have signal wire, I like Belden 9154, because it has a foil shield with drain wire (no need to bundle up a shield and tin it to put it in the ground terminal) and the leads of the hot/ground twisted pair are tinned for corrosion resistance.
Unfortunately, the hookup configuration in that link is somewhat misleading. It's fine for the miniDSP inputs, but taking one side of the output configuration to ground accomplishes nothing. The MiniDSP units have a rather high output impedance so grounding one side won't damage anything. For a simple unbalanced output from the miniDSP just use the "S" and "+" connections and leave the "-" connection unused.
I'm not sure why you would use both a miniDSP and a PLLXO. Can you elaborate?
Cheers,
Dave.
I'm not sure why you would use both a miniDSP and a PLLXO. Can you elaborate?
Cheers,
Dave.
The formula?
The required EQ is listed on the Thor page of SL's website:
Subwoofer equalization
It's two shelving filters 16-48 (10db) and 6.4-28 (13db.)
Both can be programmed into a miniDSP "basic" plugin. Advanced bi-quad programming is not required.
Cheers,
Dave.
The required EQ is listed on the Thor page of SL's website:
Subwoofer equalization
It's two shelving filters 16-48 (10db) and 6.4-28 (13db.)
Both can be programmed into a miniDSP "basic" plugin. Advanced bi-quad programming is not required.
Cheers,
Dave.
An all-pass filter creates a frequency-dependent delay....with analog circuitry. Since the miniDSP units have pure delay capability an all-pass circuit is no longer necessary and neither is physically moving the tweeter back. Physically moving the tweeter might create a stepped baffle which might cause diffractions and/or reflections that are not an issue with a flat baffle.
Cheers,
Dave.
Thanks for your reply Davey. I am a 70 y.o "newbie", not an engineer, but my experience as a professional brass musician gives me some intuitive insight into the nature of the sound one might expect from this system, IMO of course. So what I did glean from your answer is that both all-pass and pure delays are simply rough approximations attempting to compensate for what's actually going on between the drivers around the crossover point, with lesser degree of accuracy away from it, as more complex modeling of this "unique" geometry would require much more complex filtering, yes? Which, in a way, is greatly relieving, since I can now therefore simply implement the delay Behringer instead of tediously having to delve into exhaustive MiniDSP all-pass bi-quad equations, again yes?
Although I did not understand your comment about creating a stepped baffle, but take your word that the tweeter has to be where it is, this does not answer the question of what the effects of that obtrusive ( read "ugly") pipe sitting directly in front of the woofer are ( and how one filters THAT !), but that's another story...
So anyway, I was just about to head over to FlexPVC to order the required parts when I decided to do a few more calcs. Lo and behold, what to my disappointment did I notice, was, that with the Fernco coupler, the space between the coupler and the woofer's magnetic assembly at the narrowest point is less than 5/16"!! So in essence this is saying that, yes, all the bass that is supposed to fill my rather large L.R. has to get squeezed through this tiny 5/16" gap. (!!!) Doesn't anybody have a problem with this ??? Frankly, I am surprised that nobody has brought this up before. Do you think this won't have an adverse affect on the openness of the bass? So, as I said, I am not an engineer, but my first thoughts were, hey why not do away with this constriction entirely by simply making the whole bass pipe out of a straight 5" (or 6" ! ) pipe!! OK, so, as I now realize, although this might be a good solution for an ideal driver, it would seriously unload the Seas driver, which now would tend to flop in the breeze, yes? But never the less, I'd sure like to see more "breathing room" between the woofer and the coupler, if at all possibleas, I can almost hear the "chuffing" going on and can only wonder how better it would sound with less constriction in this critical area. Thanks, & nice to know you guys are out there,
Dan
Although I did not understand your comment about creating a stepped baffle, but take your word that the tweeter has to be where it is, this does not answer the question of what the effects of that obtrusive ( read "ugly") pipe sitting directly in front of the woofer are ( and how one filters THAT !), but that's another story...
So anyway, I was just about to head over to FlexPVC to order the required parts when I decided to do a few more calcs. Lo and behold, what to my disappointment did I notice, was, that with the Fernco coupler, the space between the coupler and the woofer's magnetic assembly at the narrowest point is less than 5/16"!! So in essence this is saying that, yes, all the bass that is supposed to fill my rather large L.R. has to get squeezed through this tiny 5/16" gap. (!!!) Doesn't anybody have a problem with this ??? Frankly, I am surprised that nobody has brought this up before. Do you think this won't have an adverse affect on the openness of the bass? So, as I said, I am not an engineer, but my first thoughts were, hey why not do away with this constriction entirely by simply making the whole bass pipe out of a straight 5" (or 6" ! ) pipe!! OK, so, as I now realize, although this might be a good solution for an ideal driver, it would seriously unload the Seas driver, which now would tend to flop in the breeze, yes? But never the less, I'd sure like to see more "breathing room" between the woofer and the coupler, if at all possibleas, I can almost hear the "chuffing" going on and can only wonder how better it would sound with less constriction in this critical area. Thanks, & nice to know you guys are out there,
Dan
Dan,
Sorry about that, I missed your note that you were referring to the Pluto and not the Orion.
The issue with clearance between magnet assembly and woofer tube has been brought up many times. There's even a notation in the Pluto Construction Plans to verify you have sufficient clearance. Remember, this is a sealed box, so it's not like you have a significant volume of air traveling back and forth in that gap all the time.
You could certainly use larger pipe for your enclosure, but the mounting "baffle" area should remain small for optimum response. I used 6" pipe for my latest Pluto's and with a flat profile cap installed there is approximately 0.25" around the Seas woofer. (That's maximum IMO.)
The larger volume will not "seriously unload" the Seas driver and make it flop in the breeze. The stock equalization will still work effectively but a change to fine-tune would be preferable.
The tweeter tube location above the woofer is part of the design to "deflect" woofer radiation for improved polar response and better blend with the transition to the tweeter. No filtering for THAT is necessary. There were some minor diffraction effects noted with the Pluto 1 but these were addressed with a change in geometry in the Pluto 2 configuration.
Cheers,
Dave.
Sorry about that, I missed your note that you were referring to the Pluto and not the Orion.
The issue with clearance between magnet assembly and woofer tube has been brought up many times. There's even a notation in the Pluto Construction Plans to verify you have sufficient clearance. Remember, this is a sealed box, so it's not like you have a significant volume of air traveling back and forth in that gap all the time.
You could certainly use larger pipe for your enclosure, but the mounting "baffle" area should remain small for optimum response. I used 6" pipe for my latest Pluto's and with a flat profile cap installed there is approximately 0.25" around the Seas woofer. (That's maximum IMO.)
The larger volume will not "seriously unload" the Seas driver and make it flop in the breeze.
The stock equalization will still work effectively but a change to fine-tune would be preferable.The tweeter tube location above the woofer is part of the design to "deflect" woofer radiation for improved polar response and better blend with the transition to the tweeter. No filtering for THAT is necessary.
There were some minor diffraction effects noted with the Pluto 1 but these were addressed with a change in geometry in the Pluto 2 configuration.Cheers,
Dave.
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