can anyone tell me about RADIAN COAX 12"

[tim614]

thinking of purchasing a pair to try out, im playing jbl 2226 with altec 288 with se kt88 right now and i do realy like them, but i want to try something differnt (smaller) my basement just dont have enough room and i realy want to try some coax, after reading here and there i just can find enough info.
i just wanted to know if its a good gamble.

[rcdaniel]

Not sure I can contribute much. I considered a few of their coaxials - including their new 5312 NEO - to match with an upcoming SET AMP. Their sensitivity and reputation were attractive, but I passed on them due to their relative high Qts.

Radian has a reputation for producing very nice compression drivers and I have read some comments that they loosely share a history with Tannoy and have a similar musical presentation, at a gross level. But, they seem designed for pro use / low output impedance amps and their matching crossovers, while decent, could be significantly bettered.

I have decided GPA 604-8H-III drivers in large custom MLTLs and custom crossovers. Not small and not cheap.

Note: you could possibly run with something like Wayne Parham's 4Pi speakers; similar to your current set up, suited to kt88 amps, and would work well in a small room. But, if you are looking for something rather different...

Cheers
RCD

[tim614]

thanks RC!
my current setup use the pi crossover, i do like them very much just wanted to down size.
i just wanted to see what's my option if i wanted coax.

[rcdaniel]

For a given bass response, smaller size cabinets generally require higher Qts drivers, which are less suitable for highish output impedance (ie. SET) amps. That said, I reckon a 8" Radian (pressed basket for high value) with standard crossover in a nicely tuned Pensil-style (Scott Lindgren at Woden Audio) cabinet alignment would make for a sweet-sounding moderately sized, tunable, highish efficiency speaker with a very flat impedance plot that would make it suitable for SET. It would still have the moderate Qts driver, but the flat impedance and ability to tune the cabinet would go some way to mitigating any issues, me thinks.

Cheers,
RCD

[talaerts]

I have decided GPA 604-8H-III drivers in large custom MLTLs and custom crossovers. Not small and not cheap.

This is an upgrade I would be very interested in. However, while I found various references to an MLTL design, I couldn't find a detailed enclosure plan. Do you have such a link?

best,

Tom

[tim614]

Originally Posted by rcdaniel

For a given bass response, smaller size cabinets generally require higher Qts drivers, which are less suitable for highish output impedance (ie. SET) amps. That said, I reckon a 8" Radian (pressed basket for high value) with standard crossover in a nicely tuned Pensil-style (Scott Lindgren at Woden Audio) cabinet alignment would make for a sweet-sounding moderately sized, tunable, highish efficiency speaker with a very flat impedance plot that would make it suitable for SET. It would still have the moderate Qts driver, but the flat impedance and ability to tune the cabinet would go some way to mitigating any issues, me thinks.

Cheers,
RCD

now we getting some where.
im plannig to run the radian with a pair of mono PP kt88 that im building but also i think with the small size room i have it should be ok with my "SE" kt88 .
it just that when i look at the Radian 5312 the response chart seem very nice for the job.
Tim

[spkrman57]

My quick thoughts concerning drivers. Qts, fs and Vas should all be taken in account to determine the proper cabinet for a driver.

Higher Qts drivers usually need a much larger cabinet size to avoid boominess caused by a very high resonance/impedance peak that smaller cabinets can't avoid.

Go for a low Qts driver and use a sub below if space limitations are a problem.

Regards, Ron

[tim614]

Impedance (LF/HF) 8 ohms / 8 or 16 ohms
RMS Power Rating 500 Watts
Sensitivity (1W/1m) 96dB SPL
Frequency Response 60Hz - 20kHz
Recommended Crossover 950Hz
Voice Coil Diameter(LF/HF) 4.0" / 3.0"
Nominal Dispersion 90°
Net Weight 31 lbs. / 13.64 kg.
Mounting Information

Overall Diameter 12.375" / 314.33mm
Bolt Circle Diameter 11.625" / 295.28mm
Baffle Cutout Diameter 11.125" / 282.58mm
Overall Depth 7.937" / 201.6mm
Materials

Woofer Cone Reinforced Paper
HF Diaphragm Aluminum
HF Suspension Mylar
Basket Stamped Steel
Input Connectors (HF) .25" / 6.35mm Terminals
Input Connectors (LF) Push Button Terminals
Thiele-Small Parameters

Resonant Frequency (Fs) 54 Hz
Impedance (Re) 6.0 ohms
Total Q (Qts) .3653 Mechanical Q (Qms) 2.6136
Electrical Factor(Qes) .4246
Comp. Equivelant Vol. (Vas) 55.44 Liters
Voice Coil Overhang (Xmax) 2.87
Surface Area of Cone (Sd)m2 .08208 m2
SPL vs. Frequency

[tim614]

so my quest is. what can i expect from this drivers?

[rcdaniel]

Sorry all, I had forgotten that I responded here. Quick responses:

Ron, I am aware of some of your exploits via some of your cohorts the ART forum and occasionally AA Hi-Eff. IIRC, you have been on quite a journey and have mucho more experience than I. I generally agree with your comments; however, contexts and objectives... specifics. Generally, bigger is better, but floor space and positioning constraints rule for some folks. For a simple 2-way solution that does not take up too much space, a higher Q driver is more workable, especially with some of the beyond bass reflex alignments being used these days. Also, not everyone has the space or desire for added boxes/cabling/complexity/cost of subs.

Tom, the MLTL is currently being designed for me for a very reasonable cost by Scott Lindgren of Woden (aka Scottmoose on the Full Range forum here). It will be a floor-stander that is larger than the MLTL project on 6moons; wide baffle (to minimise baffle step), shallow and reasonably tall - but not as tall as it could be. I will let you know how it goes and we can maybe work something out from there, though I'd like Scott to benefit in some way if you went ahead...

Tim, do your amps run feedback, therefore lowering output impedance? If yes, either your PP or SE KT88 should rock, even in a nicely tuned bass reflex design. If not, I guess it would depend on the cabinet used. I am not a fan of most simple bass reflex cabinets with non-feedback SE amps, though with some work they can be tuned to sound quite nice. My way of thinking is that if you wish to use higher Q drivers, the impedance through the bass frequencies needs to be flattened somewhat. Sealed and aperiodic achieve this with high Q drivers; Scottmoose has blurred the lines between some vented alignments in his Pensil designs to achieve this with medium Q drivers.

The driver Qts quoted puts them into my (arbitrary) medium Q category and usable in a range of cabinet types. Try bass reflex or if you have a few extra $, ask Scott if he thinks it is worth him doing a design - he will be honest.

Gotta run.

Cheers,
RCD