The Note panel is sort of a 3.5 way with the lower 7" midrange rolling out before the upper one. The lower midrange is compensating for the dipole roll off of the upper mid. The UE V2 can not handle this kind of "overlapping" correctly. I don't know about Acourate or AudioLense as I have not worked with them. The other issue is that a fully active Note would require a minimum of 5 channels of amplification per side. So a PC based system would also require a sound card with 10 analog outputs.
Crossover slopes are key to driver integration. Changing slopes would not make a NaO Note.
I use amps rated at 100/channel/8 ohms and 4 ohm capable.
Not at all. Since I sell the SE Guide I have my fingers on the pulse of SE sales. Additionally, SoundEasy is much more than a measurement system. It is a complete design package including a full measurement system, box design, crossover design, crossover emulation, active circuit design, system performance modeling, room finite element analysis, etc. I know over at PE the OmniMic and Arta are very popular and Jeff B's Excel based crossover, box and other spreadsheets are also very popular. Frankly, there are some things I like Arta for better than SE's measurement system but over all I find I still prefer the old IMP for plain old SPL measurement as it is a self contained data acquisition system and the most reliable. SE would be a close second but it is not straight forward to get absolute SPL measurements. But Arta has some nice display features.
Don't feel bad Michael. There are quite a few Note systems being constructed and in various stages of completion. I presume you received my email regarding the update.
Do I sense it's not Mike's fault (sorry!!).. in any case you know I'm more than willing to donate elbow grease. I have also the miniDSP stuff in case you want to hear how it would sound with them vs. hybrid etc!
It's still a hybrid withthe miniDSP. The minDPS just replaced the analog active crossover and eq for the panel and woofer. The panel x-o remains passive.
I have gotten some feedback about delays. Some builders just don't have the money right now. It's tough out here.
(The upadate is just a couple of resistor chaneges. Nothing drastic, or expensive.)
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You did not read one of my posts closely. The Seas ER18 units can not be run in parallel. The lower unit rolls off around 300 Hz the upper one at 1k Hz. This is one of the design features of the Note that perhaps I should make more clear on my web site. The filter on the lower unit is designed to allow it to compensate for the dipole roll off of the upper unit, thus requiring less dipole eq. It is similar in concept to a x.5 way conventional speaker where the 1/2 way driver is used to compensate for the baffle step loss. It also provides increased volume velocity at lower frequency so the required max SPL can be achieved. So, all 4 drivers on the Note panel have a unique filter transfer function. Here is a schematic of the passive panel crossover:
An externally hosted image should be here but it was not working when we last tested it.
You can see the ER18 arrangement.
I'm not saying it can not be made fully active, either analog or DSP, but it requires 5 channels because between the woofers, the Seas units, the SSD 10F and the Neo 3 there are 5 filter transfer function.
With a flexible digital crossover it would seem possible to duplicate the frequency response curve plus SPL of both Seas ER18 Upper+Lower midranges with a single 10" - 12" diameter speaker. I do not believe the directivity would be compromised from using a single 10" or 12" midrange. The SS 10F mid-tweeter should provide directionality for this midbass size.
Would this be an acceptable or potentially superior solution? It would no longer be a NANO_NOTE, but could still match the constant directivity goals. It would save one amplifier channel and one "evil" crossover.
Would this be an acceptable or potentially superior solution? It would no longer be a NANO_NOTE, but could still match the constant directivity goals. It would save one amplifier channel and one "evil" crossover.
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I just found someone in my area who is building a NaO Note.
Really looking forward to hearing them ! But the guy is self-confessed procrastinator
You might as well have been talking about me...
My procrastination ...
HTGuide Forum - View Single Post - S14 - 4 Way OB using Seas and Vifa/Zaph drivers
Better start on it soon. It's a step back in terms of HF directivity though.
HTGuide Forum - View Single Post - S14 - 4 Way OB using Seas and Vifa/Zaph drivers
Better start on it soon
. It's a step back in terms of HF directivity though.Other considerations.
Anyone can build anything they like, but the Note is the Note. I am sure there are other approaches to achieve the directivity goals I set fourth. It is a matter of cutting wood and testing. But do not believe that the directivity goals of the Note could be met with a 10" driver replacing the dual ER18's, without significantly lowering the crossover point to the SS10, for better or worse, and I don't want a crossover below 1k hz. It would certainly be a different speaker. I am currently looking at a design using a single 8" and that has some tradeoffs. Remember, it isn't just about below the crossover point. The mid is stlll affecting the polar response above the crossover point too.
In any event, I am very pleased with the performance of the Note as a hybrid design. My experience with the NaO II in hybrid and fully active tells me there is little to be gained by going fully active othert than added complexity and the claim of superior perfromance.
Thanks for all the info John.
I do have 10ch DAC, Presonus Firepod. Acourate can do traditional filter slopes, with linear phase. Are linear phase crossovers OK for Note?
Are Rythmik servo drivers OK for the bass? Does your analog bass EQ circuit also flatten phase with a transform?
Since you power the whole dipole panel with 100W amp maybe four LM3875 60W chips could handle it, depending on driver impedance.
Thanks
Rich
I do have 10ch DAC, Presonus Firepod. Acourate can do traditional filter slopes, with linear phase. Are linear phase crossovers OK for Note?
Are Rythmik servo drivers OK for the bass? Does your analog bass EQ circuit also flatten phase with a transform?
Since you power the whole dipole panel with 100W amp maybe four LM3875 60W chips could handle it, depending on driver impedance.
Thanks
Rich
I don't think you'll get 60W from LM3875s Richidoo. LM3886s perhaps? Sounds like you have some nice gear, but what you are moving towards is a speaker similar in some respects to a Note, rather than an actual Note- essentially a different speaker. Nothing wrong with that, but I'd've thought that designing from scratch on the basis on the strengths and weaknesses of your chosen drivers using your own design criteria would be a better approach than attempting to emulate a Note?
I'd love to hear what an "open baffle" Seas Prestige FA22RCZ (H1597-08) 8" Fullrange over a dipole woofer (pair of 10" in an "H" frame?) sounds like . . . <g>
Hi Dave, 20212? I don't know. I haven't been that motivated. I have the NaO II and the Note. I very happy with both. If I do continue with it, it will be all active using the new version of the UE or the miniDSP 2x8. And, coincidentally I will be using LM3886 amps. I have all the parts laying around my listening room collecting dusty. I also have some idea about using a different tweeter configuration. But it all seem like a lot of work because I don't think it would best the II or the Note. It would just be different.
Rich, Toaster pretty much said it all. But I will add that while I have always advocated linear phase my contributions to the UE in achieving linear phase speakers (not just linear phase filters) has me looking again. The thing with the UE is that it makes it possible to go from nonlinear phase to linear phase with no changes in frequency or polar response. It truly allows an apples to apples comparison. Everything stays identical except phase. Sometimes I think it makes a small difference, sometimes not, but the difference is not what I expected. believe I know why but I have to make some measurements to confirm. Right now I don't have the time or motivation to look into it.
Rich, Toaster pretty much said it all. But I will add that while I have always advocated linear phase my contributions to the UE in achieving linear phase speakers (not just linear phase filters) has me looking again. The thing with the UE is that it makes it possible to go from nonlinear phase to linear phase with no changes in frequency or polar response. It truly allows an apples to apples comparison. Everything stays identical except phase. Sometimes I think it makes a small difference, sometimes not, but the difference is not what I expected. believe I know why but I have to make some measurements to confirm. Right now I don't have the time or motivation to look into it.
Toaster, I was thinking that if John's 100w amp could run the whole dipole with passive filters, then one 3875 per driver in active speaker should be enough. I like the sound of 3875 better than 3886, but midwoofers might need the extra power.
I don't like opamps. Even though there are only 6 stages in Note's EQ, that's a lot for my ears, so I'd rather do without them if possible. PC can do all of the required filters for the whole speaker in math, so why not? My questions are aimed to make sure that I don't change John's concept when I use active amplification. In my mind, the filters are just math. John already offers a miniDSP version of the analog active filter board for Note. I'd want to take it further with active amps and digital crossovers since I already have software and multichannel DAC. I don't see it as changing anything about the design, but it's OK if it does. If it doesn't work I can always build the analog filters. John has done the hard work, replacing coils with equations is easy as long as I use the same functions.
John, your comments about the value of linear phase crossovers is very interesting. On some of my speakers it is obvious effect, but less so on others. I think the effect is more pronounced at lower frequencies. Actually Dirac advocates linear on LF filters and minimum at HFs. It is a cool feature of UE to be able to turn it on and off so easily.
I don't like opamps. Even though there are only 6 stages in Note's EQ, that's a lot for my ears, so I'd rather do without them if possible. PC can do all of the required filters for the whole speaker in math, so why not? My questions are aimed to make sure that I don't change John's concept when I use active amplification. In my mind, the filters are just math. John already offers a miniDSP version of the analog active filter board for Note. I'd want to take it further with active amps and digital crossovers since I already have software and multichannel DAC. I don't see it as changing anything about the design, but it's OK if it does. If it doesn't work I can always build the analog filters. John has done the hard work, replacing coils with equations is easy as long as I use the same functions.
John, your comments about the value of linear phase crossovers is very interesting. On some of my speakers it is obvious effect, but less so on others. I think the effect is more pronounced at lower frequencies. Actually Dirac advocates linear on LF filters and minimum at HFs. It is a cool feature of UE to be able to turn it on and off so easily.
First the single amp vs multi amp argument is a doubled edged sword. If you consider a 2 way with woofer and tweeter rated at 90 dB/2.83V and if you argue that you need to be able to driver each driver to a minimum of 110dB then you need a biamped system with 2 100W amps (40 V peak each) or a single amp rated at 400W (80 V peak) to assure that both drivers can receive a peak signal of 40V at the same time. That argument is fine as far as it goes. But the realization is that the single amp system does have 6 dB dynamic head room over the biamped system. While the single amp 400w amp is capable of handling any signal the 100W biamped system can, it can also handle signal that would drive either the woofer or tweeter alone to 116dB.
Looking at it as a math problem, if A is the voltage delivered to the tweeter and B the voltage to the woofer the biamped system says,
A must be < 40V
B must be < 40 V
while the single amp system says,
A + B < 80.
Clearly the last statement is more the more general case.
So on one side you have "if I need XX dB from the woofer and tweeter then the single amp system needs to have 4x the power of the amps in a biamped system. But if you say I want the same dynamic capability form both then the amps in the bi amped system need to be of the same power rating as the single amped system. As usual, the coin has two sides.
Then there are the argument about IM distortion and current load on the amps which might be significant if we were living in the 1950's.
About linear phase and low frequency, yes, that is where I predominately hear the difference. While I did not want to discuss this at this point because I don't have measurement yet to back it up, since it has come up, and since perhaps others have come to similar conclusions, I'll state my thinking.
Low frequency in room response above the fundamental, and particularly just below the Schroeder frequency, is dependent on the sum of contributions from several modes. How these modes sum will be dependent on the phase of each mode, which in turn will depend on the phase of the source. If you look at a typically woofer the phase changes most rapidly as the cut off frequency is approached from above. This is also evident in the group delay with increase form zero, peaking around the cut off and becoming constant below the cut off frequency. This is the characteristic of any high pass response. Linearization of the phase of the source should therefore have a pronounced affect on the phase of the room modes and how they sum. It isn't clear that this would be an improvement, but it would seem that it should certainly be different and audible. And, it should not be difficult to verify with measurements.
I should make a point of setting up a comparison of this with the UE at next year's DIY with my dipoles. I've got it set up now with them oriented in the long dimension in my basement, back to the stairs. It's definitely an improvement.
The other thing I'm doing is using my Velodyne ULD-15 for the very low end. It's crossed where I used it with my old Apogees, 45Hz BW1. It is supposed to be flat down to 20Hz. As much as I tried to EQ those Peerless woofers, it never satisfied at the very low end. I often don't realize that the Velodyne is doing anything until music has some over done bass in it.
The best thing is that my wife is no longer complaining when upstairs working.
The orientation (since the tweeter is not dipole) and with the damping in the woofer rear section it is surprising how much louder I can play it without incurring her wrath!Incidentally, this somewhat places them about 1/3 from the end wall in the long dimension. When I stop to just listen I sit about 1/3 from the other end. The overall response seems best this way, even a small adjustment sitting closer to the other wall quickly changes it.
I've been curious, maybe you can provide some clarity. The Velodyne is driver from the fourth UE2 channel as you suggested or at least close to it. It's running bandpass with LR4 HP (I think you suggested BW2) at 5Hz and with LR2 LP at 99999Hz to have the same delay as the mains. I use the Velodyne control for the power setting. I switched from BW2 to LR4 for two reasons. One, I wanted the best low end extension and to minimize the earlier rolloff above the Fc by going LR4. I also thought that when using the linear phase option, I would need to use the LR rather than the BW, but it's probably a moot point.
Of course, this doesn't really provide a flat, linear phase through the subwoofer contribution area, I have no measurements to import into the UE. Plus with the 99999Hz lowpass, the only area of interested is the woofer HP and that is not likely coinciding with the natural HP of the sub. I don't have an idea what that is, I've never considered measuring the Velodyne. I've always set that by ear since the room modes are such an issue.
With a BW1 LP at 45, I suppose it is a situation of experimentation as a good part of its output coincides with the low end of the stereo pair that are EQ'd with the UE and there's no sub EQ at the LP of 45. It's something along the lines of multiple subs located around the room, though I only have one true sub. The dipole woofers are set to HP LR4 at 18Hz.
Have you ever experimented with using the UE to linearize phase of a subwoofer and integrate it with the mains?
Dave
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The best thing is that my wife is no longer complaining when upstairs working.
Have you ever experimented with using the UE to linearize phase of a subwoofer and integrate it with the mains?
Dave
I like LOUD so if Jeanne complains I just turn it up until I can't hear her. Then she starts flicking the light switch and I think, wow, a free light show,
I haven't done much with the UE lately other than work on the manual for V3.
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