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Ergo Number Nine - Adventures in Micromonitor Design

If anyone feels the need of the sub woofer with them they should have got a bigger speaker in the first place. Anyway, a subwoofer would only bring back neighbour problems.

The only time I could see you wanting a subwoofer is if your reasons for using a small speaker were space related but you had room to tuck a sub in out of the way some where.

Steve
 
vuk said:
...but bosss, where are zee pictures???
Click to expand...
Posts #201 and #240 on pages 14 and 16, Vuk. Apologies for hasty use of flash, but all the more excuse for your visit so you can take some proper photos to do them justice (and take the walnut cabinets back with you).

James
 
Are you planning to finish the wallmount version with grill? It would be interesting to see the final specs.
 
Yes, I will be. Eventually. The wall mount version calls for a completely different XO, for which I don't have all the part yet. But the good news is, I have grill cloth!

James
 
Hi James,

Another great looking speaker project.

Been following your threads with interest, I see that you have tried quite of a number of drivers. Bass aside, how would you describe the differences between the midrange performance of the CA18RLY, 18W8530, CA15RLY, slit paper and the poly excell units.

Jag
 
Hi Jag,

Great to have you on board.

It's hard to describe differences per se, because it's not always down to the driver alone that makes the midband special. The crossover network has a significant role as well. So perhaps the most appropriate comments I can make should be in the context of my experiences of them, and what I consider to be their strengths and weaknesses (if any).

CA15RLY - Sounds natural but is a little uneven tonally.

CA18RLY - Both natural and dynamically sounding, but not the most 'detailed'.

MCA15RCY - More dynamic than CA15RLY and more detailed than CA18RLY. Best value midrange driver.

M15CH001 - Stunningly real and smooth midrange, easy to work with too. The only downside is they're no longer available.

15M4531K - Very lively sounding, dynamic and detailed, but can be a bit fatiguing if the rising response is not tamed.

15W8530K01 - A most organic and fulsome sounding driver. Really hard to fault in a small box, and easy to work with too.

18W8535-00 - I used to think this was the best sounding midbass driver, until I heard the 15W8530K01. Again very natural and organic sounding, but gives some detail away to the little Revelator.

PHL1120 - Stunning dynamics and virtually unlimited headroom. Fantastic presence, but not the most tonally accurate driver. Requires a lot of correction in XO, and probably best suited for active crossover.

Dang! Have I really played with that many mid-range drivers? Ask me about my favourite woofer. ;)

James
 
James how would you describe the imaging/ soundstage qualities of your little beauties? ie do they 'disappear' well? maybe its a quality thats either inherrant to your initial design/ choice of drive units, or just a facet of serious quality drive units Im not exactly used to (tho my HB1s are quite good at it!)

Also would you totally advise against mdf for the cabinets? cost being the point of the Q. Cheers for sharing your super designs to us mortals BTW.

Capt
 
Hey Capt,

I'm not particularly sensitive to imaging, and I don't really much care about the precise location of the second bassist relative to the tinkly triangle in 3D. The only important thing image wise is that they are correctly sized and you can hear a voice as if it is coming from a defined spot that approximates the size of a real person, and not one that is plastered diffusely all over the wall. If you want to know if you can tell exactly where the E-IXs are when you close your eyes and just listen, that very much depends on the recording, but I'd say it's generally so.

I have no issue with the use of MDF, or any other material. However, that won't be an exact replica and I can't guarantee the outcomes. It might sound worse, it might sound better, I won't really know. Solid hardwood is stiffer and hence the resonance frequency of the panels would be higher than MDF, but whether that is audible I can't say. With regard to cost, I'd say a 2.5m x 250mm plank of hardwood (not endangered species) is a minor item compared the Scan-speak 15W drivers. MDF would no doubt be easier to work with, and you can make-do with simpler butt joints (if veneering or painting) rather than biscuited mitre joints.

James
 
James said:
MDF would no doubt be easier to work with, and you can make-do with simpler butt joints (if veneering or painting) rather than biscuited mitre joints.

James
Click to expand...

exactly the reason I ask (rather than cost actually).. butt joins (with a 20mm cleat I -think- would be rigid enough) is only realistic for me, & a decent veneer job to finish.. I could never in a million years get 45 degree joins like yours as much as Id love to use hardwood.

Dare I ask (in lieu of the ls3/5a cabs being so)- would plywood perhaps be a better choice acoustically, have you ever used ply? sacriligeous Q so it is. Im not worthy.
 
Capt,

Marine-grade or birch ply would be just fine, and a lot closer to the mechanical characteristics of hardwood timber. I used marine ply for the PFM-Specials and the inner carcase of the E-Vs.

James
 
Markus Sauer said:
Do tell us about your favourite woofer(s).
Click to expand...
The Scan-speak 25W/8565-01, stunningly crisp and accurate sounding woofer that works wonderfully in a sealed box of around 60L, and goes down to 40Hz (-3dB) - which means a realistic 25Hz in a room. It is fast, sufficiently dynamic with 88dB/2.83V sensitivity, and kind to amplifiers with a nominal 8-ohm impedance. Best of all, it is a reasonable US$220 each.

I just wished Scan-speak made a 12 or 15-inch version.

There is a new driver manufacturer that has sprung from past Scan-speak associates making drivers in Indonesia under the SB Acoustics brand. They have a 12" and forthcoming 15" woofer that promises to be very reasonbly priced.

James
 
RustyB said:
The answer's probably called Betty. Woof!
Click to expand...
LOL! For those wondering who Betty is, she's my Labrador Retriever.

2962925-md.jpg


James
 
Nice woofer!

James you say in #1 the scanspeak was chosen for its similarities to the kef b110: could therefore the kef be used as a drop-in instead of the scanspeak, ie with the morel tweeter & this x-over etc?

(anyone) what is 'marine ply' exactly compared to std 12mm birch ply?

cheers Capt
 
The Captain said:
James you say in #1 the scanspeak was chosen for its similarities to the kef b110: could therefore the kef be used as a drop-in instead of the scanspeak, ie with the morel tweeter & this x-over etc?
Click to expand...
No. The loose similarity ends with the T/S parameters. The acoustic response is quite different and you won't be able to swap drivers.

Marine ply is simply plywood that meets BS1088 standards of durability, absence of voids and strength. Birch plywood is, well, plywood made from Birch I guess.

James
 
Ah, no sooner had I posted that message than I realised the inductors have a measurable impedance and that is accounted for in the calculations (and therefore the schematic).

Silly me, panic over!
 
Another question though: do you use any kind of wadding/filler inside the IXs?

Edit: and another... the sandcast resistors, are they wirewound? What's their power handling? I see Madisound have wirewound/sandcast 15W and 25W.
Edit again: scrap that, the 7.5R is only available in 15W.
Edit once more: where did you get those lovely M8 fixings that you used to fix the front and backs of the speakers to the cabinets? They look fabulous.

Thanks,
Carl
 
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