Advice - Replacement drivers for Castle Chester speakers

[bug2k11]

I used the Dayton Audio DATS tester with the driver clamped upright on a bench (there was a couple of metres of free air around it).

There seems to be quite a few drivers with 177mm outside diameter.

[bug2k11]

Here's some pictures showing the back and a larger front picture.

Rear View

Front View

[5th element]

You know I'm sure I've seen a basket design that looks like the rear of that before, specifically the casting around where the screw holes/flange are, it isn't Audax, but I cannot quite remember what, either that or I am remembering incorrectly!

[planet10]

Originally Posted by bug2k11

I used the Dayton Audio DATS tester with the driver clamped upright on a bench (there was a couple of metres of free air around it).

You will likely need to actually test any replacement drivers with the same kit to get numbers that can be compared.

The manufacturers data is (almost universally) done using LEAP or LMS at much higher driver levels -- which, unless the driver has flat T/S curves, means a different set of numbers, sometimes dramatically so.

dave

[PeteMcK]

the SEAS CA18RLY might be suitable:
H1217-08 CA18RLY

[system7]

As Planet10 (Dave) says, the Chester is a paper cone.

Carbon fibre Castle
Not one, not two, but three hew loudspeakers have been recently introduced from Castle - the Avon, the Eden and the Keep. The newcomers complete Castle's 1996/97 range and introduce its first foray into the. audio-visual arena. The Avon replaces the Chester and, together with the Eden, brings carbon fibre technology to the Castle range for the first time. This two-way, floor-standing design employs a 165mm bass/midrange newly developed by Castle.

Review | Carbon fibre Castle | Page172 - November1996 - Gramophone Archive

I stand corrected. Crossover suggests about 0.9mH inductance (Le) to me at a wild guess.

[speakerman19422]

I think the woofer is an Audax that is no longer available. The center of the back plate looks similiar to the Audax drivers I used in the early 80's. They made a lot of drivers.

[bug2k11]

I've picked up a pair of these Seas Prestige H1217-08 CA18RLY
I've measured them with the Dayton Audio DATS and these are the paramters for each:

* Manufacturer: Seas
* Model: H1217-08 CA18RLY
* Piston Diameter = 125.0 mm
* f(s)= 44.41 Hz
* R(e)= 6.04 Ohms
* Z(max)= 28.37 Ohms
* Q(ms)= 2.647
* Q(es)= 0.717
* Q(ts)= 0.564
* V(as)= 24.860 liters (0.878 cubic feet)
* L(e)= 0.92 mH
* n(0)= 0.29 %
* SPL= 86.72 1W/1m
* M(ms)= 10.93 grams
* C(ms)= 1.18 mm/N
* BL= 5.07

* Manufacturer: Seas
* Model: H1217-08 CA18RLY
* Piston Diameter = 125.0 mm
* f(s)= 44.41 Hz
* R(e)= 5.99 Ohms
* Z(max)= 29.82 Ohms
* Q(ms)= 2.526
* Q(es)= 0.634
* Q(ts)= 0.507
* V(as)= 24.860 liters (0.878 cubic feet)
* L(e)= 0.90 mH
* n(0)= 0.33 %
* SPL= 87.25 1W/1m
* M(ms)= 10.93 grams
* C(ms)= 1.18 mm/N
* BL= 5.37

Original Castle mid/bass drivers:

* Manufacturer: Castle
* Model: Chester
* Piston Diameter = 125.0 mm
* f(s)= 71.33 Hz
* R(e)= 5.49 Ohms
* Z(max)= 59.38 Ohms
* Q(ms)= 6.439
* Q(es)= 0.656
* Q(ts)= 0.595
* V(as)= 10.250 liters (0.362 cubic feet)
* L(e)= 1.00 mH
* n(0)= 0.54 %
* SPL= 89.43 1W/1m
* M(ms)= 10.27 grams
* C(ms)= 0.48 mm/N
* BL= 6.21

* Manufacturer: Castle
* Model: Chester
* Piston Diameter = 125.0 mm
* f(s)= 66.62 Hz
* R(e)= 5.55 Ohms
* Z(max)= 63.98 Ohms
* Q(ms)= 5.847
* Q(es)= 0.555
* Q(ts)= 0.507
* V(as)= 11.420 liters (0.403 cubic feet)
* L(e)= 0.85 mH
* n(0)= 0.58 %
* SPL= 89.74 1W/1m
* M(ms)= 10.57 grams
* C(ms)= 0.54 mm/N
* BL= 6.65

Measured a little different to the published data, but as some have said may be due to the levels used to test. I'll get the cabinets modified to fit them, be interesting to see how they measure with the existing crossovers.

[sreten]

Hi,

Note that the cone masses are similar, so the differences in Vas and Fs
are very mutual. Also the lower BL of the Seas driver probably indicates
more excursion, but with lower sensitivity.

The x/o looks fairly standard and may work well with treble L-pad adjusted.

My limited experience of putting higher Vas and lower Fs drivers into tuned
1/4 wave boxes is not good, a serious case of one note bass resulted.

But I guess you'll have to suck it and see.

rgds, sreten.

[speakerman19422]

Originally Posted by sreten

Hi,



My limited experience of putting higher Vas and lower Fs drivers into tuned
1/4 wave boxes is not good, a serious case of one note bass resulted.

But I guess you'll have to suck it and see.

rgds, sreten.

Sreten what was your choice of stuffing material that resulted in one note bass?

Many claim good results with fiberglass. Many old articles in books and magazines of it being to reactive compared to wool and low density polyurethane foam.