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Just thinking in terms of making a new 2-channel amp with built-in crossover for biamp duties.
nCore is a logical starting point having plenty of power and a good reputation, as well as being Available.
MiniDSP is the choice for crossover and you it'll have a line level output for a sub in either balanced OR single ended.
Here is my first block diagram. Later, I can do a drawing and work out placement as well as overall size of enclosure. I'd like a drawing of the BASE of the nCore amp so I could try to source an appropriate finned heatsink.
Follow Ups:
I built a similar thing ; that's the front panel. Anodized aluminum, bloodwood trim, and the knob is ground from red tigers-eye stone, with a small (man made) ruby set into the aluminum knob base as the knob pointer.
Here's the insides
Here's the speaker that I use with this
Satori 6.5" midwoofer in ported 0.75 cu. ft. enclosure with Bozhen ribbon tweeter
ONE amp for both speakers?
I see 2x of the TP60 amps and another amp marked 'tweeter'.
What MiniDSP did you use and why? Was it the quietest of simply the right feature set?
I'd like to see your block diagram.
The 8 volt transformer is for Mini power? I see the 24v section for tweeter power.
Too much is never enough
MiniDSP 2 x 4 is what I used, based on price and capability. The tweeter amp is a TPA3116D2-based amp I bought off eBay. 8 volt transformer feeds the +5 V regulator for the digital stuff.I can't remember what voltage the TPA3116D2 amp runs off, on the block diagram I sketched I put 22 VDC but I can't recall, maybe it's 18 VDC.
I replaced the stock output coupling electrolytics of the Mini-DSP with some film caps I just happened to have on hand, mounted outboard there as you can see. Not sure this makes it sound any better but I had them on hand....
This was built for a bedroom system. Using the Dell tablet running Squeezeplay, I can control playback audio track selection and volume from a web browser on any device in my apartment, like an Android tablet I use in bed. I have 60,000 FLAC files of music on a Logitech Media Server setup, and of course one can also listen to various streaming Internet "radio stations" - I particularly like Soma FM's 256k Groove Salad stream.
I can also take the Dell tablet and the chassis over into my workshop and use it to measure / biamp / EQ other 2-way speakers I might make.
So far I have built two speakers for these electronics:
Satori 6.5", ported, with Bozhen tweeter
and
Scanspeak 7" Revelator sealed with Bozhen tweeter
Both use 0.75 cu. ft. enclosures.
Edits: 06/08/17 06/08/17 06/08/17 06/08/17 06/08/17
I think you will find that the miniDSP performs better single-ended even when driving a balanced input amplifier (the S/N is several dB better). You may want to validate my claim prior to investing in the wrong one.
I have heard some about differences between the 2x4 (original) and some of the later products. I/O voltages and more are discussed.
Valid Point for further research:
The 2x4HD is all balanced and a good candidate for what I want to do. Single channel IN to 3 out.
That being Hi / Lo / Sub. This is a new product.
Input / output levels are among the questions I have. This is where I'm currently concentrating my noodlings.
The 2x8 would be overkill but also work. Phoenix connectors would provide direct wiring from the MiniDSP to the amp, without additional connectors. Shielding would be preserved.
Too much is never enough
Bi-amp is great. Tri-amp is even better.
Some people concern themselves with "power division", etc. Forget that bullshit.
You need to select a crossover which does what you want and doesn't sound like crap.
Cross at something like 125-150 Hz. This keeps it out of the MAIN range of most musical instruments. Audiophiles typically don't know that. Audio engineers and musicians DO. ;)
Regarding speaker cables: 12 gauge twisted pair is fine. Don't obsess over "shorter lengths". Five feet, fifteen/twenty feet, whatever. The audiophile world is filled with BS.
I don't know anything about nCore, so I can't help you there.
:)
Connecting Amp/Crossover to Pre with balanced and using the shortest feasible speaker cables minimizes opportunity to pick up Any Stray RFI.
All things being equal, given sufficient wire gauge, I won't worry about speaker cable length until it hits maybe 10 feet or so. Maybe 15.
Case by Case basis.
Technically, a pair of 2 way speakers with a sub IS a Three-way and therefore Tri-Amped. I wouldn't know where to begin trying to Triamp a 2-Way speaker. ;)
Crossing the sub as low as 50hz, acts to remove the lowest octave from the Main Speakers addresses several considerations at once.
Crossover to sub is low enough to prevent ANY thought of localizing it.
Main amps are relieved of a small but real amount of power need, transferred to sub. This has the effect of moving the 50:50 power point a BIT higher, which with my 1.6 Maggies, is all to the good.
I'd never cross a sub above maybe 80hz, which is what you find in an HT receiver.
Too much is never enough
If you're going to do a single (one channel) sub, 50 Hz/24 dB per octave is about the max, depending on your hearing and listening sensitivity.My point was regarding stereo subs. 125-150 Hz takes a LOT of the load off the main speakers, and is a good crossover area, without having to be concerned with localization and/or having a crossover in a bad musical instrument place.
I understand that powered/crossed "subs" (plural) with a bi-amped two-way speaker is, in fact, a tri-amped speaker. What I said is that tri-amping is even better than bi-amping. That is basically what you're doing, except that your main speaker manufacturer didn't tell you that you'd want an add-on woofer, and that, if you want to use just one, cross it very low.
Lastly, again, do not worry about 10-15 foot speaker cable lengths, especially with regard to stray RFI. Your RFI/EMI/hum interference is going to come from your low-level component interconnects and from having your components connected to multiple outlets, as well as from your and your neighbor's electronic kitchen oven temperature sensors. For home listening, 20 feet of 12 gauge twisted pair will get you into "the zone" and will be fine. Chill out, dude!
:)
Edits: 05/29/17 05/29/17
I think you're right.
With STEREO subs, a higher crossover point can be sustained. Maybe it'd even be of further benefit to imaging / stage width?Trouble in this case is my awful room, which is 8 sided, very asymmetric AND has a peaked ceiling of about 11 feet. I'd gues maybe 5000 cubic feet or so.
The sub when located on the LEFT side (facing speakers from listening position) turned my den into a helmholtz of sheer boominess. The left side was intened to take advantage of being nearer a corner.
The sub ended up on the right side, oriented parallel to a wall and away from corners. Indeed, the sub is near to the hallway to the back of the house. That location is MUCHO better. The entry to the den in question is on a 45 to the main walls in the LR, and at a 90 to the wall from hell, which is at a 45 to the plane of the speakers, 6 feet wide and 10feet tall. Can you spell absorption?I also use OPTIC connection in several places where single ended would do as well. This avoids ANY potential for RFI pickup.
Too much is never enough
Edits: 05/29/17
A-b-s-o-r-p-t-i-o-n.
Absorption.
;)
With the ONE addition I made many years ago, room ain't half bad. I put a thickish woolen tapestry on the FAR wall to tame an echo. It is spaced 2" from the wall.
Sitting position is unfortunately near the mid-point of the LONG dimension of the room, but not QUITE. Bass with the sub on the right side seems very well distributed now and even. Sticking my head in the various corners doesn't seem to show any 'peaks'.
I've got plans for diffusors to go Behind the speakers where they'll do the most good.
Maybe I should send off for some OC703 and build something for the Big Wall, which is at a 45 to the plane of the speakers and not THAT far away.
Too much is never enough
Sorry if I was not clear. I was replying to your question: "Can you spell absorption?"
It was supposed to be a joke. :)
Regarding your woolen rug on the wall... I'd have to look it up, but I think you're getting most of your absorption between about 125/200 Hz and about 500 Hz. I'm not sure if that's what you want. Check out "Master Handbook of Acoustics" and "Acoustical Designing In Architecture". They both have very good guidelines for absorbers. Also, the ASTM has a lot of this kind of info. Lastly, for the cost of a not extremely expensive turntable/cartridge, you can get a real acoustician to come in to evaluate your room.
:)
If I had extra coin? I'd be tempted to get an ISF guy here to do a TV tuneup.
The new generation of OLED sets are nothing short of Spectacular. The new '7' series are supposed to be better. I have a 2016 'B6' which blows me away. No 3D, which makes me dizzy with those horrible glasses and only OK source material.
I'd make 2'x4' panels using OC703 or similar in 2" thickness. 2x framing and a couple cross braces would provide anti-racking while choice of 'grill cloth' for acoustic transparency and appearance. But I would probably make DIFFUSORS first,
Too much is never enough
This is one of the advantages of bi-amping horisontally. IE one stereo power amp doing bass in L & Right channels. And, one PSU and stereo power amp doing just mid-treble.The bass PSU may from time to time be a bit stressed when playing loud or complex music. and you won't hear that in the mid/treble as you might with just one power amp.
The half power point is around 350Hz but 600Hz is near enough if using matching amps, the amp doing <600Hz might be working 1-2 db harder on average. But on loud orchestral tuttis it may be working 3db harder, twice the power.
What does the passive crossover in your panels do? Are both the HighP and LPass set to -3db at the same frequency? (It would be a good thing to find out.) If it's not symmetrical the Mini-Dsp box/es may well do a better job of blending them than you can.
You will need a good mike and stand sitting between where your ears will be.
Warmest
Tim Bailey
Skeptical Measurer & Audio Scrounger
Edits: 05/26/17 05/26/17
That PS areguement "may' have plausibilty with Linear supplies. But it seems (guessing tho) that you are using SMPS gizmos on the Hypex things. Decent smps feeds directly from the mains... Bass won't sag it.
How did YOU know? It IS a Gizmo600 SMPS!
And yes, I suspect that given a bandpass of maybe 50hz to 600hz, that the amp will not be able to tap-out a 600watt PS.
Too much is never enough
Panel crossover is at 600hz.
I do NOT know the 'knee' frequencies,
But that being said, the Low Pass is 12db (2nd order) while the High Pass is 6db (1st order)
They CROSS at 600hz to sum flat THRU the crossover region. The 1st / 2nd order thing means they are also 90 degrees apart.
Using my Preamp, I CUT the lowest bass to the panels at 45 or 50hz which buys me a few percent and puts the crossover frequency closer to 50:50 than running full-range. The crossover in the preamp is 12db / octave.
I think that can be duplicated in MiniDSP with a little experimentation.
In my 'noodle' each amp module has its OWN 600 watt PS. Another version would include a 1200 watt PS module with outputs for a pair of the nCore.
Limiting bandwidth TO the power amp(s) buys as much as 3db AnyWay, so I would't be overly concerned with a few watts here or there. I'll buff-up the heat sinking on the nCore amps using some kind of maybe 100mmX100mm finned heat sink. I need a PRINT of the mount of the amp so I can take it to a machine shop to have the holes PRECISION drilled and tapped.
If I had a little math help, (logarithms?) I could BACK compute the knee freequencies given crossover at 600hz and the slopes. I should be able to, anyway.
Too much is never enough
or Speakers.Also see 'discourse about off-audio topics'? above :-)
I do have some experience with bi-amping and I do not completely agree with of the established view-points about bi-amping. But, I'd rather post about that elsewhere, say 'Speakers'.
Or you could search there on 'bi-amping' against my moniker.
How do I get this moved to a more appropriate category?
You will get a lot of very definite advice which 'may' / 'will not' be systemic, to your own system / plans.
Happy to discuss, off-line, too.
:-)
Are you going vertical or horizontal? Just asking. Learning
Will
The intent here would be to put ONE of these modues behind EACH speaker.
You'd need one balanced line TO the module and a source of clean AC. I consider short
speaker runs to be a good thing.
You'll need to do some independent research.
It's very difficult to simply tell you what to do or encapsulate in a legible fashion.
If you ask a couple concise questions, I'm sure you'll get a few answers.
For example: My panels cross over about 600hz. Given that I low cut to the panels, I figure that the HF and LF need about the same amount of power. So running a pair of same amps is a reasonable solution.
Your problem / solution is likely different, so my answer may not solve YOUR issue.
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