As I said, I'm not big into amps, particularly all the inexpensive stuff that is out there today. I can only comment on what I have. My basic recommendation is for 100/8, with 4 ohm capability. Such amps should be able to drive the woofers in parallel even if using the XXLS or XLS woofers and push the system (and you ears) to its limits.
Hi John, I see 100W into 4ohms is necessary for the subs/4th channel. However, for those with a different sub set-up (low power requirement), what would the top 3 channels get by on? I want to drive the top 3 from the Miniamp, which is 10W into 4ohm - medium sized room, moderate listening levels. Thanks.
You get an additional 3dB of output by doubling power, so you should be about 11dB down using a 10W amp rather than 100w, all else being equal. In practice manufacturer's/ designer's amplifier power ratings are not always accurate and how much distortion you are getting at an amp's rated maximum may vary from manufacturer to manufacturer. the sensitivity of the Note main panel is about 89-90dB, so it will go as loud as any other speaker of that sensitivity with your amps. The bottom line is to give it a go and see if is loud enough for you. If it isn't there are lots of inexpensive higher-powered amps available if you DIY. Some of the cheaper class D amps are very good value.
Thanks Toaster for the reply to SAC. I agree with most of what you are saying, but make that 10 dB down. One thing to realize is that if you install the rear tweeter you are looking at about 2 ohm load to the tweeter amp. There isn't much power to the tweeters so the low impedance should not bother most amps. I'm currently experimenting with the Class D Audio amps. I placing a miniDSP 2x4 and two CDA254 Class D Audio amp boards in the base of each speaker. The Class D amps roll off quite a bit on top due to the interaction of the inductive output filter with the tweeter load, but I think that can be corrected with some EQ. So becareful with class D amps as the output filtering may roll the top end off significantly. The Note II has been well received by the diy community.
It has also lead me to some updates tot he NaO II RS which I guess will be the NaO II RSa. While the NaO II in RSa form will continue on, it will be available in digital format only.
Thanks for your input Toaster. I am considering buying the Miniamps but only if someone has experience of using them successfully with the NaO Note II. They are certainly attractive in being easy to power/connect to the minidsp.
If anyone has experience of the Miniamp running 90db speakers, or better yet the NaO Notes, please let us know.
If anyone has experience of the Miniamp running 90db speakers, or better yet the NaO Notes, please let us know.
Note enough power (pun intended).
You might just get away with 10w going into the speaker if you don't listen very loud.... however you can bet the miniamps (no time to go to the spec sheet now sorry) will be rated for 10w at too-high distortion.
There's plenty of cheap class D at around 25-50w which would be a much safer bet. Although these won't stack with a 2x4 minidsp board, which I can understand might be an attractive proposition.
Me?! I just received my plans, and am hoping to knock together a quick and dirty version once I return from my honeymoon next week (yay!).
Even if they're only a brief point on my journey, John deserves to get paid. I've spent more (and learned less) on a book before.... compared to what John has up on his website.
MiniDSP datasheet;
2 x 20W @ 8ohms, Continuous power BTL
4 x 10W @ 4ohms, Continuous power SE
THD + N (half power) 0.05% (BTL) / 0.08% (SE)
So, SE or single ended, is 0.08%, but "half power". That means at half of 10W I think, so distortion is good at 5W!?
Gazzas' question is relevant here it seems.
Enjoy the honeymoon Dave.
2 x 20W @ 8ohms, Continuous power BTL
4 x 10W @ 4ohms, Continuous power SE
THD + N (half power) 0.05% (BTL) / 0.08% (SE)
So, SE or single ended, is 0.08%, but "half power". That means at half of 10W I think, so distortion is good at 5W!?
Gazzas' question is relevant here it seems.
Enjoy the honeymoon Dave.
SAC (Thanks) ... That's right. 0.08% @ 5w (or 10w BTL) .... Not enough unfortunately.
Gazza. Doesn't really matter.... John means.. 8 x 100w @ 8ohm .... with the ability to drive 4 ohms (which would normally mean more power @ 4ohm)
That is enough power to take this speaker to it's limit. IMHO if you had an amp which was more like 100w@4ohm (and less power, say 75w@8ohm)... This would also be fine, assuming you weren't trying to send yourself deaf ;-) ;-)
Also keep in mind that dual tweeters need a 2ohm capable amp if you run them parallel.
Gazza. Doesn't really matter.... John means.. 8 x 100w @ 8ohm .... with the ability to drive 4 ohms (which would normally mean more power @ 4ohm)
That is enough power to take this speaker to it's limit. IMHO if you had an amp which was more like 100w@4ohm (and less power, say 75w@8ohm)... This would also be fine, assuming you weren't trying to send yourself deaf ;-) ;-)
Also keep in mind that dual tweeters need a 2ohm capable amp if you run them parallel.
To drive the SLS woofers in parallel an amp rated at 100w into 8 ohms and capable of driving a 4 ohm load. Typically the amp would have a higher power rating into 4 ohms. I use a pair of Adcom 7605, 5 channel amps which are rated at 125/8, 175/4 and they are much more powerful than really required. 50 W/8, 90 to 100 into 4 would probably do fine for most but I like the amps to have plenty of head room.
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The tweeters are only drawing power from 6k Hz and up. There isn't much up there so the 2 ohm load is not a problem for most amps. The biggest problem I have seen is with class D amps, specifically the Class D Audio CDA 254 amps. They have no problem driving the speakers but due to the inductive output filter the 2 ohm load rolls off the tweeter response significantly (down 10dB at 20k Hz). Adding a high pass shelf should correct this but I haven't tested it at this point as I had to send a couple of my CDA 254 amp boards back to Class D Audio to have the gain reset to match the newer units I bought recently.
That should probably work fine. To increase the tweeter gain you would go into the tweeter parametric EQ (channel 7 or 8, they are linked), select EQ4, choose Biquad, set B0 = 2, click Process. That will raise the tweeter output level by 6dB.
Sounds like a good solution for any amp that doesn't like the 2 ohm load. Why didn't I think of it?
Tried something fun with my Notes today. Exchanged the dipole bass for THAM12 tapped horns. Raised the crossover to 120Hz 48dB LR and added some delay to the panels. Now I can play loud with a punch and they still sound very good! The THAM sounds a lot better than regular vented boxes, the only downside is they only play down to maybe 50Hz.
A successful experiment that I will continue to explore with my own dipole panels.
A successful experiment that I will continue to explore with my own dipole panels.
Tried something fun with my Notes today. Exchanged the dipole bass for THAM12 tapped horns. Raised the crossover to 120Hz 48dB LR and added some delay to the panels. Now I can play loud with a punch and they still sound very good! The THAM sounds a lot better than regular vented boxes, the only downside is they only play down to maybe 50Hz.
A successful experiment that I will continue to explore with my own dipole panels.
Jonas, you have the original note. Which woofer system were you using with it before? As I recall you had your own dipole woofers mated to the Note panels. Is that correct?If so can you describe the dice and which driver was used, and how you EQ'ed the woofer?
That is correct John. I use the Acoustic Elegance IB15 in H-baffles. I don't remember the exact eq but you gave me some starting values to feed the minidsp (taking the IB15's t/s and my baffle into account) and I then adjusted them a bit to my liking. My H-baffles are really nice, better than the XLS12 W-baffles I had before, and probably more correct than the th. The th just have an addictive dynamic and "tight" sound wich make them great fun to listen to. I will go back to the dipole bass with the Notes, this was just an experiment to try out the th/dipol concept.
Btw, love the Notes!
I just though you might be interested in this:
Powered by miniDSP | miniDSP
I would also like to note that I have been investigating the use of two miniDSP 2x4 units in conjunction with two 4 channel digital amplifiers (Class D Audio in my case) allowing the crossovers and amplifiers to be build into the base of each speaker. This is, of course, a directed, simple, and obvious extension of the use of the minDSP crossovers. The up side is that only a single line level cable need connect the speaker to the source. The down side is that the 2x4 units are only 48k sampling.
I also would like to point to DSP_challenge
It seems too that Mr. Linkwitz has finally realized that the future is in dsp.
Powered by miniDSP | miniDSP
I would also like to note that I have been investigating the use of two miniDSP 2x4 units in conjunction with two 4 channel digital amplifiers (Class D Audio in my case) allowing the crossovers and amplifiers to be build into the base of each speaker. This is, of course, a directed, simple, and obvious extension of the use of the minDSP crossovers. The up side is that only a single line level cable need connect the speaker to the source. The down side is that the 2x4 units are only 48k sampling.
I also would like to point to DSP_challenge
It seems too that Mr. Linkwitz has finally realized that the future is in dsp.