The manufacturing plant where I work participated in a BC Hydro sponsored lighting efficiency upgrade about a year ago wherein something in the order to 100 8ft and 40 4ft old technology fluorescent lighting fixtures were replaced with the latest and greatest electronic ballasts and tubes. Even after the heavy rebate by Hydro, our cost was "several" thousand $.
Thanks to the lack of capacitive reactance of these fixtures to balance the huge inductive load of large production saws, CNC, Edgebander, and tons of hand held woodworking tools, we are now seeing a power factor surcharge of anywhere from $50 to $80 included on our electric bills which still average over $1500/mo. Now, try to do the math on payback for corrective measures - including the initial electrical survey which needs to measure the load/reactance of all major machines to determine the value and best locations of balancing capacitors, and you can get a headache that requires a fine single malt to mitigate (as of this writing - see time stamp- a Jameson's is serving nicely) .
Oh BTW, we've had more of the new technology ballasts fail in the first year ( 10 at last count) than 12 year old ballasts did in the past 3 years, and guess what - who's covering the "warranty"? But the lighting is nicer, and the tubes are purported to last much longer.
the cheque's in the mail
yes, I will so respect you
you know the third one, right?
Thanks to the lack of capacitive reactance of these fixtures to balance the huge inductive load of large production saws, CNC, Edgebander, and tons of hand held woodworking tools, we are now seeing a power factor surcharge of anywhere from $50 to $80 included on our electric bills which still average over $1500/mo. Now, try to do the math on payback for corrective measures - including the initial electrical survey which needs to measure the load/reactance of all major machines to determine the value and best locations of balancing capacitors, and you can get a headache that requires a fine single malt to mitigate (as of this writing - see time stamp- a Jameson's is serving nicely) .
Oh BTW, we've had more of the new technology ballasts fail in the first year ( 10 at last count) than 12 year old ballasts did in the past 3 years, and guess what - who's covering the "warranty"? But the lighting is nicer, and the tubes are purported to last much longer.
the cheque's in the mail
yes, I will so respect you
you know the third one, right?
Three guesses where those new ballasts are made, and the first two don't count.😉
The "full spectrum" tubes are really nice.
jeff
So that i can embed the information into drawings i made a "fancy" pdf for the info GM posted.
dave
Interesting reading - thank you Bob for bringing this to our attention.
Chrisb, interesting real life case study... looks like we still have quite some way to go before any changes in "real" cost of ownership/running... 🙁
Regards,
Zia
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Thank you GM for the math.
And Dave thanks for incorporating it into a nice "changing port size for dummies" format... 🙂 very nice illustration.
Now I have no excuse to delay the port measurement and subsequent installation! My candidates - one slightly over 3 inches in diameter, one slightly less.
-Zia
Attachments
A little question regarding TLs using these drivers( I don't want to start another thread just for this)
The cross section of a TL using say, a chr70 or similar sized TB
some designs seem very generous, almost over generous; obviously the cross sectional area of the line should be larger than the cone area but what is the least one can get away with?
The cross section of a TL using say, a chr70 or similar sized TB
some designs seem very generous, almost over generous; obviously the cross sectional area of the line should be larger than the cone area but what is the least one can get away with?
built-in BSC?
I have another theoretical question, this one regarding BSC for the EL70 MT.
It has been said that a bipole arrangement mitigates the presumed need for a BSC that a monopole with the same driver/cabinet would call for. However, this being a MarkAudio driver, there is an engineered increase in output (from ~ 200-500 Hz with the EL70) to approximate a built-in BSC.
So, in theory, would this bump be prominent when playing music? Does anyone recall experiencing such a coloration when listening to music through the EL70 MT's?
I know I'll probably be tweaking with my MT's in-room response after I have them playing, but I'd like to get some anecdotal perspectives, too.
Thanks!
Marc
I have another theoretical question, this one regarding BSC for the EL70 MT.
It has been said that a bipole arrangement mitigates the presumed need for a BSC that a monopole with the same driver/cabinet would call for. However, this being a MarkAudio driver, there is an engineered increase in output (from ~ 200-500 Hz with the EL70) to approximate a built-in BSC.
So, in theory, would this bump be prominent when playing music? Does anyone recall experiencing such a coloration when listening to music through the EL70 MT's?
I know I'll probably be tweaking with my MT's in-room response after I have them playing, but I'd like to get some anecdotal perspectives, too.
Thanks!
Marc
Attachments
Line cross-section has no direct link to cone area. It is a function of Q & Vas.
dave
The volume of a line is a cross-section & a length. In essence an appropriate volume is found, divided by the length to get a cross-section. With tapers & such, a bit more complex than that thou.
dave
dave
Yes what I thought; I used the program supplied on Madisound and it gives me a volume v close to what I had assumed. But some designs, especially a tabaq design I saw, has a very large internal volume for the driver used. I would have thought an optimum volume tapered line is more suitable for small FRs ie adding some back pressure for the cone
madisound one gives some useful info. If i get this build past concept stage I will def use the MJK one
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Planet10,
You have big expirience with bipolar speakers, I`d like to ask your advise.
I know and like all good features of bipolars, but also observed less exact localisation of the images. Scene is wide and deep, but images are more duffuse than usually.
Did you observe the same feature in your bipole projects?
You have big expirience with bipolar speakers, I`d like to ask your advise.
I know and like all good features of bipolars, but also observed less exact localisation of the images. Scene is wide and deep, but images are more duffuse than usually.
Did you observe the same feature in your bipole projects?
if I can have 1.5 meters from back wall - will localisation degrade essentially?
If I make back driver offset - close to floor- will it increase degradation of localisation?
If I make back driver offset - close to floor- will it increase degradation of localisation?
I finished my MTs this morning. They are covered with cherry veneer with a clear finish. The walnut trim at the bottom was dictated by the size piece of veneer I bought, which was 96" long. Since the MTs are a hair over 33" tall, the math didn't work for full coverage so I opted to add the contrasting wood.
I burned in the drivers for about 180 hours before assembly and they sound really sweet right off the bat. I am pleasantly surprised at the bass - not quite as good as my Half Changs, but very respectable nonetheless.
I burned in the drivers for about 180 hours before assembly and they sound really sweet right off the bat. I am pleasantly surprised at the bass - not quite as good as my Half Changs, but very respectable nonetheless.
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Bobtrancho,
Excellent work. Very elegant and professional looking speakers. Good to see the Micro Tower club growing 🙂. The speaker feet you have are shaped exactly like mine, but better looking! Your timing is impeccable also - you've finished within the 2 week estimated time frame you mentioned earlier.
-Zia
Excellent work. Very elegant and professional looking speakers. Good to see the Micro Tower club growing 🙂. The speaker feet you have are shaped exactly like mine, but better looking! Your timing is impeccable also - you've finished within the 2 week estimated time frame you mentioned earlier.
-Zia
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