Right, [much] too low a compliance [Vas], too high a mass [Mmd or Mms], so bi-amp, preferably with at least class A amps and preferably some type of tube amp for the HF, preferably SET or low DF PP.
For instance, the Radian 5215B has < half the averaged 604 series [Vas] and > 2x its [Mmd or Mms]!
For instance, the Radian 5215B has < half the averaged 604 series [Vas] and > 2x its [Mmd or Mms]!
Well, based on this 1957 spec sheet and the standard driver frame diameter Vs [Fs] BR chart DIYers used back then, the 6 ft^3 should be tuned to ~60 Hz, plenty low enough for the times whereas it's 26 ft^3 for its 40 Hz Fs where the [3/4"] baffle thickness vent area [Av] = driver [SD].
So, duct port the 6 ft^3 to 40 Hz or ?
So, duct port the 6 ft^3 to 40 Hz or ?
Dave that design looks very nice. Different from so common "washing machine" type box.
Is it available? Maybe some day I buy GPA 604 pair.
Victor
That 15” Celestion seems like a really nice bang for the buck but looking at the frequency responses both the 15” and 12” Celestions seem a tad worse than the Sica or the Faital.
Now I just have to find out the correct way to calculate the volume for these big coaxials.
The dips at 6kHz and 9kHz for the 12" and the 1,5kHz peak and 5kHz dip for the 15" sure doesnt look good on paper but at-least they might be honest with no smoothing.
I think all coax have a bumpy ride on paper but some toe-in and some distance may even out that. Id love to see some mild off axis measurements at 3m.
I think I'm going to buy the 12" anyway, I'm obsessed with 12" coax in a Heresy box design - summer looks bright with lots of box building again. Hoping 70l gives decent response.
Ill probably get the Kappalite neo CX too at some point, hoping for price reduction soon, I just love the fact that I can replace the HF with any screw-ons and play around - the betas have been fun times and I want to try the PSD2013 driver at some point too.
Higher priced coaxes seems to focus more on time alignment with shared magnets, I understand this is a better design (like Faitals, BMS, B&C) but the flexibility is limited.
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@ Cal...I know you love your Altecs...no doubt they sound even better bi amped.
I have been so tempted to try a 604E or 8G that I’ve seen for sale for a
a while now...both are $2500...gulp!...haven’t had the nerve.
@GM...Yes, you explained well what I was encountering in my research on
many of the modern coaxials (especially the Radians).
Although I still have my old Quicksilver push/pull horn monos, I doubt
I would use them (they may need to be sold on).
My desire would be to use my First Watt projects (ACA, F2J and soon
VFET) for the HF section.
For LF I would try using some hypex amps I am just wrapping up
some enclosures for.
I have been so tempted to try a 604E or 8G that I’ve seen for sale for a
a while now...both are $2500...gulp!...haven’t had the nerve.
@GM...Yes, you explained well what I was encountering in my research on
many of the modern coaxials (especially the Radians).
Although I still have my old Quicksilver push/pull horn monos, I doubt
I would use them (they may need to be sold on).
My desire would be to use my First Watt projects (ACA, F2J and soon
VFET) for the HF section.
For LF I would try using some hypex amps I am just wrapping up
some enclosures for.
a Karlson K15 w. 604E and N1500 is the best I've heard with Karr's "SPIRIT OF KOUSSEVITZKY" album. Brace your K15 well. One K-person braced the wings like Gauss did with their 5181 K18 cabinet. Until a few years ago I didn't realize Karlson marketed a "K18". It might be possible to improve upon K15 with some experimentation and the reflector suggestions of patent 3540544. For a testbox, I would make the front chamber a couple of inches more shallow than with K15 as K15 has a front shelf which does some corrective things.
Just out of curiosity, how BIG is that box? I mean that driver has to be at ear level SO that would make the box like 60 inches tall?
Yeah that 12" is also extremely well priced. Probably the cheapest of them all. I might try that one for the first project before I move to something bigger.
But I can see it already. A nice translam ported box with aluminum front, rounded corners both inside and outside and some serious bracing.
Probably a decimal error in one of the TS parameters.
I think 70-100l would be great for it.
But supply is slow now, out of stock.
Here’s an older design/driver example: DIY Home Hi-Fi kit with coaxial driver - Celestion
Btw would you be able to sim the response with the suggested xo?
https://celestion.com/wp-content/uploads/2019/09/FTX1225-crossover-design.pdf
Says 48Hz at 60l.
I think 70-100l would be great for it.
But supply is slow now, out of stock.
Here’s an older design/driver example: DIY Home Hi-Fi kit with coaxial driver - Celestion
Btw would you be able to sim the response with the suggested xo?
https://celestion.com/wp-content/uploads/2019/09/FTX1225-crossover-design.pdf
Says 48Hz at 60l.
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But take a look at the Vas. The TF1225CX is 1.5 9ft3 and the FTX1225 is 0.43 ft3. Unless it’s a typo on their part.
I’ll try to play with the crossover and simulate it but honestly I’ve build only full range speakers before. This will be a first for me.
I’ve also looked again at the Eminence Beta 12” but they are so cheap (2x woofer 2x tweeter) I feel like they can’t sound nice.
I’ll try to play with the crossover and simulate it but honestly I’ve build only full range speakers before. This will be a first for me.
I’ve also looked again at the Eminence Beta 12” but they are so cheap (2x woofer 2x tweeter) I feel like they can’t sound nice.
Nothing wrong per se with the specs per the math I posted earlier to get the correct results. Hint, it's a lot smaller, tuned lower than the guesstimates.
That said, your posted site is wrong [now one too many times for me, so personally will ignore it in the future] and didn't notice it was a 12", so [Sd] is way off, which in this case won't affect basic box/tuning, so in the future recommend using factory specs [which sadly aren't always 'close enough' either] unless some more accurate measured ones aren't available: https://celestion.com/productpdf.php?id=992
I have the Beta 12. Its a nice driver. With the PSD2002 sounds pretty cool with electronic music. However the mid range is muffled/bumpy so I think it require DSP or a much more complex XO to work properly for other types of music.
I want to try the Celestion to see if its any better mids or if I need to invest more (Kappas etc).
I want to try the Celestion to see if its any better mids or if I need to invest more (Kappas etc).
Apparently no typo based on its Vas/Cms specs, so basically a sealed or TL alignment is required due to the need for a very long > ~4" dia. vent to tune it at a low enough vent mach.
It's an inexpensive true prosound high speech intelligibility co-ax, i.e. is optimized for the ~ 250 - 8 kHz [5] octave BW, so while its specs are fine for BR loading, it ideally needs a woofer, the HF drivers historically needing some tweaking/EQ.