Tweaking Castle Conway 3 speakers

[Richard]

Hi Bob, all,

Yes indeed, great to meet up, Bob made me very welcome and I couldn't believe we'd been chatting 3 hours by the time I left with 2 very heavy bases!

We joked there were no tolerances on the drawing and Bob said it was ok, he'd made them exact dimension, he had too Good job my measurements were good Bob, you were right about those mount holes btw, checked the old bases and the holes were 9mm in them!

They fitted exactly, drop on swap and perfect alignment! Very much heavier and completely stable when the spikes are adjusted to the floor, no wobble or flex in the new base plates.

The sound is definitely changed and I'm still getting a handle on it. Tighter bass with better definition for sure but the treble is also clearer. I tried with 1 spacer between cabs and plinths as before, then 2, then back to 1. Very interesting and will post more as it will take a while to get to grips with!

Here are the pics, 25mm steel, 12Kg each, machined and powder coated in sky blue pink - err, satin black - and I can assure anyone Bob does a super job,

[david counter]

WOW they do look nice, very well done Bob

cricky I've woken up
where have I been

[bob orbell]

So glad they fit OK Richard, reading your post about the spacers had me a bit puzzled, but I think I have it now, do they have a downward firing bass unit that exits inbetween cab. and stand? and the spacers are to adjust the port size. BOB

[Dik Dolan]

Fabulous job bob=)
I'm disappointed they aren't pink though, you could have videoed Richards expression as you handed 'em over, that would've be great to see. =)

[Richard]

Hi Bob, all,

The drivers all face forwards but the port is in the base of the cab firing down onto the plinth base. The gap between base and cab can be adjusted using 4x 4mm thick washers stacked 1 2 or 3 high. The bigger the gap the larger the volume of bass but the higher the tuned frequency. In my room I'd found 2 washers swamped things with bass and 1 washer gap was much better being less amount but going slightly lower in f.

I agonised a bit about making bases from steel but decided it should be a good thing. The port gap will affect the frequency the port is tuned to but the material the base is made from will attenuate any direct sound out of the large cabinet port hole. Clearly 25mm steel will block sound much more than 25mm mdf and so the port will still function and be adjustable but direct sound from it will be reduced.

What would happen with the mdf base I think is that some direct sound at lower frequencies would travel through the base and, in my case, reflect from the conrete floor after another inch or so of spike height, underlay and carpet. If the floor were suspended type that sound would travel further still and perhaps be lost. So whatever the floor these bases will make for a more consistent sound in that regard anyway. Of course this may not be the reason and it may be just down to the extra mass and firmer location these bases provide.

The sound is now much clearer and bass strings and drums really resonate and play tunes. At first I interpreted this clarity as less volume of bass but then realised it went at least as deep but was not as muddled. Making the port larger with 2 washers was like turning up a bass control, still clear but too much volume so I reverted to 1 washer.

So a great result, clearer deeper bass and clearer too further up the range, for whatever reasons, which was a surprise.



Full HFW review and description of the workings here, http://www.castle.uk.com/LinkClick.a...language=en-US

[bob orbell]

I can just remember reading an artical in Hi-Fi answers a long time ago about one reader placing heavy slabs of concrete on top of his speakers, saying that they sounded better, his logic was that the speaker cab. must not move, if it dose, then the sound from the drivers will be distorted, so, when I made a pair of transmition line speakers I took the approach of putting the mass down below, on the base, and it works. You can try the slab test for yourself, I think you maybe supprised at the result.

[colin.hepburn]

Yep I have to agree with adding mass I use silver sand in the stand columns full to the top weight is about 56lb for each stand and about 2lb on top of the speakers which are fixed with three pea sized bit of blue-tak to the stands
I find that the speakers are much tighter focused and bass is solid tight and can be followed all the way down its range works very well in my room I need to add a concrete slab under each stand to lift of the wood floor
The sand bag on top is not that WAF friendly thou but that’s not an issue for me but will have to get something to put them in
Beware of Using Sand thought
Don’t forget sand sticks to magnets and in tweeters etc not good

[bob orbell]

Here is my home made stand's, 20mm solid base, the silver post has a 30mm round tube welded inside (for the cable to run up) and the void is full of lead, very heavy ,and the four feet are adjustable, far better than the Monitor Audio stand which are cast aluminum, I feel they were too light.

[Richard]

Yes, we saw and heard these at Bob's and they are superb build, totally professional appearance with 20mm steel bases and VERY solid, top class work

[Richard]

Hi all,

A quick update to this thread and these speakers.

After fitting "Bob's Bases" they became clearer throughout the range. I see I actually said then, "So a great result, clearer deeper bass and clearer too further up the range, for whatever reasons, which was a surprise."

Back into hifi this autumn I revisited this, changed the tweeter resistor back to 3R3 and bingo, spot on lovely. Integrated and clear treble. So I think the weak and wobbly bases had been allowing the lower frequencies to muddy the sound. I'd lifted the treble but was aware it soon became detached. Cleaning up the cabinet/LF sound and reverting to the original xover values has made the improvement to air and detail that was missing.