I recently got back into HiFi and loving the new technologies of streaming, digital and DIY.......I just ordered a pair of C-Note speaker kits because of the review here on ASR. I see there are hundreds if not thousands of these kits sold over the years. Being a DIY product, the folks that buy this kit have no issue getting their hands dirty. Has anyone designed a "Next Generation C Note" upgrade. Using the drivers and the crossover but building a different style cabinet. Maybe a Transmission Line Cabinet? Or adding a second woofer in a larger cabinet? Small floor standing cabinet?.......Might be fun!
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C-Note Speaker Kit Major Modification???
- Thread starter RoyB
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I did exactly that, for no better reason that I don't like how the original enclosure looks.
Kept the volume intact, made the box narrower, and deeper.
I did not measure it (will do, eventually), but to the ear it sounds without obvious faults.
Kept the volume intact, made the box narrower, and deeper.
I did not measure it (will do, eventually), but to the ear it sounds without obvious faults.
Without changing drivers or crossover there isn't really much that can be done.
The one thing I would suggest is optimizing the port geometry, and adding damping material to the cabinet walls. The stock build suffers from some resonances.
The one thing I would suggest is optimizing the port geometry, and adding damping material to the cabinet walls. The stock build suffers from some resonances.
Are you willing to share the sketchup plans for your build?
I once made a set on the same drivers. I didn't fully realize then that there is a popular kit named "C-note". The box and crossover are different. The crossover is designed to linearize not only system spl, but also the PR (and related) characteristics. The box is filled with polyester fiber to suppress standing waves. It is made of 18mm plywood, no veneering, just sanded and waxed (surprisingly high WAF achieved by simple means).
More details (including full off-axis measurements in H&V planes) can be found here: Mechano22
Measured sys spl for both units
Simulated sys spl and PR based on H&V measurements
More details (including full off-axis measurements in H&V planes) can be found here: Mechano22
Measured sys spl for both units
Simulated sys spl and PR based on H&V measurements
The C-Note centre speaker kind of fulfills the first suggestion.
The other suggestions seem to be along the lines of the TriTrix.
Personally I think taking the C-Note drivers and putting them in a bigger cabinet as a 3 way with an 8" Dayton woofer might be interesting.
Maybe make the new cabinet in 2 halves with the same volume as a C-Note above and a separately ported section below for the woofer to sit in!
I know, I know - Probably a hideous idea. I was thinking out loud...
Interesting point, Wolf.
But wouldn't making the 'c-note' half of the new enclosure infinite baffle drastically alter the bass extension and efficiency of the 5" driver, necessitating more radical xover changes?
I was thinking one might just shorten the port in the 'c-note' section of the enclosure and maybe reduce C4 a little from the standard 6.8uF.
Of course there would have to be a complete new xover section for the new 8" woofer.
This represents a full stretch of my current knowledge of crossover operation. I would want to read a lot more before risking amps and drivers.
But this is a large part of what DIY audio is all about for me - learning and building things!
But wouldn't making the 'c-note' half of the new enclosure infinite baffle drastically alter the bass extension and efficiency of the 5" driver, necessitating more radical xover changes?
I was thinking one might just shorten the port in the 'c-note' section of the enclosure and maybe reduce C4 a little from the standard 6.8uF.
Of course there would have to be a complete new xover section for the new 8" woofer.
This represents a full stretch of my current knowledge of crossover operation. I would want to read a lot more before risking amps and drivers.
But this is a large part of what DIY audio is all about for me - learning and building things!
I should mention here that I built my c-notes to be electrically, volumetrically and dimensionally pretty well standard but out of 18mm (3/4") rather than 12mm (1/2") MDF, all rebated joints, and a 6mm (1/4") roundover on the inside edge of the mid/bass driver cutout. There is half a pack of fibre wadding in each too.
From the very first time I saw the design I was always dubious about the rigidity of the front baffle where the drivers overlap and the panel is only 8mm thick and about 20mm wide. Indeed, other people put stiffeners, dowels or a shelf there, probably for the same reason. The 18mm panel seems to improve things quite well on its own beefing it up to 14mm thick, less a little bit of rounding over.
TBH the best thing for the C-Notes is a sub.
They sound a lot better for it. I turn my sub off in the evening but leave the active crossover running. They sound sweetly effortless when the 5" drivers aren't struggling with frequencies below 118Hz.
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moonlight rainbow dream
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Yap, would agree that building a sub or two is the most practical way of augmenting the c-notes.
Converting it to a dipole speaker using this formula would be really interesting though.
Converting it to a dipole speaker using this formula would be really interesting though.
But which sub?
My setup with preamp, active crossover and 2 pairs of amps is almost the most expensive/involved approach. I do use a really affordable $40 Dayton DVC sub driver because 'project sub' was meant to be cheap. Then I came over all enthusiastic and also discovered how expensive half decent passive crossover components are.
A home brewed cabinet, sub plate amp and DVC is probably the way to build a simple and inexpensive sub.
A dipole. Hmmmm!
I saw nothing mentioning IB Cnote implementation. It sounded like keeping the kit intact from an upgrade standpoint. If you are only using them to 120Hz, you aren't using the port response anyway. Additionally, the added rolloff of the ported design and the midrange leakage from the port will be more difficult to augment with a xover to get good summation.
If you want to try a soft foam ball, sock, or something similar in the ports initially to try it out, it will show you what I mean.
If you want to try a soft foam ball, sock, or something similar in the ports initially to try it out, it will show you what I mean.
Hi again Wolf.
I am pretty new to speaker building - the sub was my first attempt, which is why I was initially determined to keep it cheap! If it turned out to be an abomination then what the heck!
The C-Notes were partly a fun project, partly something to do with the half sheet of MDF left over after the sub project, and mostly a chance to learn something - even if it was only joinery!
As I mentioned above I did want to make some obvious improvements (3/4" MDF, rebated joints) and incorporate some small, cheap and easily reversible mods (Visaton speaker damping, 0.22 uF cap). However, I was not so arrogant as to think that I, an absolute beginner, knew better than the guy that designed them. Also, I wanted to be reasonably sure that I would get a usable pair of speakers out of the process.
As an educational project I learned a lot. And I continue to learn from them - a gift that keeps on giving.
So I will take your suggestion and stick a sock in them to see what happens!
Of course I now have more speakers than I know what to do with (4 pairs and the sub) - and I still want to build some TriTrix TLs. Is this normal behaviour?
DVDdoug
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If you change the woofer and/or cabinet volume you'll need some speaker design software to optimize the port or the software may indicate that a sealed design is better. I've used WinISD (FREE).
It's not just woofer size... A different driver will have different Thiele-Small parameters and the cabinet will no longer be "tuned" correctly.
It's not just woofer size... A different driver will have different Thiele-Small parameters and the cabinet will no longer be "tuned" correctly.
That's why I thought I would build a two chambered cabinet - one C-note sized and the other separate one for the additional 8" woofer.
As it goes I am leaning more towards building another proven design - the TriTrix TLs.
I do need to check out WinISD.
Oh yes - just vinyl wrapped the C-Notes.
Look good - just don't inspect them too closely!
I have rediscovered that cast iron guarantee that a new piece of kit is better than what you had: I keep hearing new things in albums I have had for years. The other telltale is putting on a track to 'test' the new kit and next thing you know you have listened to the whole album!
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This is definitely not a bad idea, there are many speakers that use this technique. For the DIY'ers the most recent one is the GR Research BRUTE. Cheers.
I bought a C-note kit as soon as it was aval. and was not impressed w/ the results and they sat around for a couple of years unused.
Eventualy, I decided to try and do something w/ them, so I installed the cross-over and tweeter that Matt Grant designed for his NEXUS series of speakers;
www.hificircuit.com
To install the larger tweeter, I lopped the ND25 tweeter off the wave guide and siliconed the ND28F-6 in it's place. It fits exactly the same and one would be hard-pressed to see any difference once installed.
Matt's X-over is complex w/ a high componet count and he had to go back and revise it;
Matt wrote, "The TM had an unexpected peak near 900hz and....... I ended up doing (another) full set of measurement(s) with a crossover fix for that peak."
The extent that Matt went to w/ the X-over probably tells us something about the original C-note's deficiencies.
Putting $200 of X-over parts into a $100 kit is hardly a "value endevor", but they sound great and if a guy (or gal) have a nicely finished pr. of C-notes that are gathering dust like I did, I think it's worth it.
Eventualy, I decided to try and do something w/ them, so I installed the cross-over and tweeter that Matt Grant designed for his NEXUS series of speakers;
Project NEXUS... A timbre matched family of Hi-Fi/HT speakers
Timbre matched family of Hi-Fi/HT speakers all based on the same midwoofer (Dayton DS135-8) and tweeter (ND28F-8). These designs came about from my...
www.hificircuit.com
Matt's X-over is complex w/ a high componet count and he had to go back and revise it;
Matt wrote, "The TM had an unexpected peak near 900hz and....... I ended up doing (another) full set of measurement(s) with a crossover fix for that peak."
The extent that Matt went to w/ the X-over probably tells us something about the original C-note's deficiencies.
Putting $200 of X-over parts into a $100 kit is hardly a "value endevor", but they sound great and if a guy (or gal) have a nicely finished pr. of C-notes that are gathering dust like I did, I think it's worth it.
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