After some PM conversations I would like to make clear I didn't use the Black Beauty original crossover initially because it simulated badly. In the interests of better audio I just spent an hour rewiring one of my speakers with the original crossover and I cannot recommend it.
The result was a very sibilant thin sound and the measurements reveal why. I would recommend that people building this design don't use the original crossover and instead use my design or one of their own devising (as mine doses have slightly subdued treble – for young ears). In addition to these measurements I also found the -3dB point of my speakers to be approximately 75Hz by measuring very close to driver (5mm) at very low volume as to not excite room nodes. Unfortunately I accidently deleted this measurement but there was also a +2dB boost at 100Hz so it might be worth slightly increasing the internal volume of the speaker to get an even lower -3dB and getting rid of the boost. Myself I don't mind the boost at all as it makes the speakers more 'punchy'.
The measurements are far from rigorous conducted in room with the speaker on the edge of my desk at about 1m distance but they do show what I heard. This speaker design is very good but to build it with the original crossover unless your hearing is damaged beyond 8 KHz would be crazy. The scale should be read as relative as no attempt was made to measure absolute SPL and the increase in efficiency of the original crossover forced a reduction in volume to prevent clipping. The microphone is a homemade one using the same capsule as the EMC8000.
The original crossover is to the left and mine is to the right, just used LTspice to draw them.
The result was a very sibilant thin sound and the measurements reveal why. I would recommend that people building this design don't use the original crossover and instead use my design or one of their own devising (as mine doses have slightly subdued treble – for young ears). In addition to these measurements I also found the -3dB point of my speakers to be approximately 75Hz by measuring very close to driver (5mm) at very low volume as to not excite room nodes. Unfortunately I accidently deleted this measurement but there was also a +2dB boost at 100Hz so it might be worth slightly increasing the internal volume of the speaker to get an even lower -3dB and getting rid of the boost. Myself I don't mind the boost at all as it makes the speakers more 'punchy'.
The measurements are far from rigorous conducted in room with the speaker on the edge of my desk at about 1m distance but they do show what I heard. This speaker design is very good but to build it with the original crossover unless your hearing is damaged beyond 8 KHz would be crazy. The scale should be read as relative as no attempt was made to measure absolute SPL and the increase in efficiency of the original crossover forced a reduction in volume to prevent clipping. The microphone is a homemade one using the same capsule as the EMC8000.
The original crossover is to the left and mine is to the right, just used LTspice to draw them.
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I've been perusing the CHR-70 threads because I think it's a driver that suits my needs - and there's so many plans for it. Problem is - what to build?
I was going to build a single driver Lotus (and build it so I could add a 2nd driver, if needed). But, I'm not so sure that it will fit the bill for all the types of music that I play. I listen to a wide variety - everything from acoustic guitar (Larry Coryell, Adrian Legg, Angel Romero, etc), film scores/orchestral/classical, jazz, rock and the occasional classic heavy metal (Black Sabbath, Judas Priest, etc.)
My music room is a small 12' x 15' and I sit about 8'-10' from the speakers.
I don't want a sub, but do want quality bass fairly low - not boomy.
I've got 2 sheets of 18mm 5' x 5' BB waiting, and the drivers should be here in a couple of days. Not that I'll start on it right away though.
Maybe dCHR-Ken? Although, I think this hasn't been released yet. Beta only?
I was going to build a single driver Lotus (and build it so I could add a 2nd driver, if needed). But, I'm not so sure that it will fit the bill for all the types of music that I play. I listen to a wide variety - everything from acoustic guitar (Larry Coryell, Adrian Legg, Angel Romero, etc), film scores/orchestral/classical, jazz, rock and the occasional classic heavy metal (Black Sabbath, Judas Priest, etc.)
My music room is a small 12' x 15' and I sit about 8'-10' from the speakers.
I don't want a sub, but do want quality bass fairly low - not boomy.
I've got 2 sheets of 18mm 5' x 5' BB waiting, and the drivers should be here in a couple of days. Not that I'll start on it right away though.
Maybe dCHR-Ken? Although, I think this hasn't been released yet. Beta only?
Hi Don,
The Ken-Mar cabinet's are very attractive as well. Only builder's with an appreciation for the finer aspects of art will be using these.
Best Regards,
Terry
Don,
I much prefer the term: "Activated Polyester Tone Sauce" over Bondo. It accentuates the transformational aspects, while leaving behind the more pedestrian perceptions and usage.
I'm still working on my drywall project (mud & sanding stage), which does help in fine honing one's skill in the ability to sculpt "APTS".
I haven't been in my shop for awhile either. We've experienced an extreme cold spell here in Seattle where the temperature has taken a precipitous fall into the low 80's and high 70's. It's nearly impossible to do anything in this intense cold spell!
Best Regards,
Terry
You have the deepest sympathy from Bob Cratchett here.
Bah, Humbug!
BTW, There's a new RAF smilie here:
Terry's exaggerating ( I know - hard to believe, huh? ) the balmy weather in the Great Northwest just a little bit - it's been averaging lows of around or just under freezing for the past week or so, certainly nothing like the central/mid west will be getting slammed with over the next few days - it's gonna get ugly.
just think of the projects you could imagineer while floating in the isolation tank
BTW, let me thank you for the suggestion on the Bushmills - very nice indeed
Especially in some of the more northerly countries where alcohol consumption (and lack of daylight) seem to be an issue.
jeff
Now there's a thought.
Ah, I've started something. You're welcome, not half bad is it.
yup, nope
20W continous, however at this level peaks can be expected to be +10dB therefore amplifier power level should be 200W. However at 20W input power your probobly excursion limited at low frequancies anyway so 200W amplifier is excesive.
what exactly do you mean by "bear" - Mark's spec sheet note 20w nominal, but I know for sure you can make some pretty (if not thunderingly loud) music with 1/4 if that, and I'm sure there are folks who haven't melted the voice coils or deformed the cones from over-excursion with 3 or 4 times that amount of SS (e.g. home theater receivers)
If you don't already have a particular (type of) upgrade amp in mind, probably a better question would be - "I have xxx model, and my room is yyy big, what class/range of power should I consider?"
expect lots of helpful advice
FWIW, it's long been a trope in audio shop service departments that the number one killer of tweeters was too little power - nasty heating of voice coils by distortion products when amps are run into continuous deep clipping. Perhaps not so much of an issue with full range drivers with their generally more robust VC and excursion capacities.
Ok. I have a couple of bb4.al speakers (basically chr70 2gen) on an MApensil-R70 (147mm x 902 x 229) enclosure from Mark's site.
An externally hosted image should be here but it was not working when we last tested it.
The amp I use is based on tripath 2024. The room where i listen to music is about 4X5 mt.
I like a lot the sound of the speakers with this amp, but some times I would like listening to the music louder.This amp theoretically has 15w output, but only 10 - 11 clean watts.
I'am choosing a new amp, Tclass one. That is why I am interested of knowing how much power will brake my loved bb4. Should I buy amp capable of 40w output, 100, 300?
Hope my question is more clear now, despite of my english
Nolberto
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