There was one from B & K, with a large bike-chain drive on the front, I think heterodyning. Analog.
Jan
Jan
Gee Frank, that you should have so little faith ...
Karan Acoustics KA-i180 will do it just fine, at 180W/W and for around €6,000 a pop.
If you're feeling blue, a second hand Marantz 1182DC integrated, at 86W/8 Ohms, will do it as well, Anatch has already lined up a few very useful pointers on what to change. Latsly, for around €120 locally, a H/K 6550 integrated will literally shine with new caps and a changed volume pot. WARNING - highly addictive sound.
dvv,
My house in the realm of things here in California isn't even large, some of these mini-mansions and mega mansions are just plain silly for the fact that only two people may live in them. 10 bedrooms and 20 bathrooms, I guess they can't walk a few more feet to get to the bathroom and must be playing musical rooms so their other half can't find them!
My original design for my 6 1/2 cone driver does go lower than what your friends speakers are capable of but it comes at a cost. One I have only about 86db efficiency@ 1 watt and many would freak out if they saw the VAS number which requires a large box for tuning. I am using a 1 1/3 cubic foot enclosure with this cone driver in a ported enclosure.
I am a bit behind on the conversation so I am trying to see who said what. Whoever said that they disagreed with Richard about the boundary changing the crossover slope, I would have to agree with that, the in-room measured response may change but the slope of the real output from the speaker at crossover isn't truly shifting, those are boundary induced measurement changes at the measurement position.
I think perhaps it was Max who put up this paper, if it was thank you for that reference, if it is someone else thank you instead.
Henri Korhola
Perceptual Study of Loudspeaker Crossover Filters
My house in the realm of things here in California isn't even large, some of these mini-mansions and mega mansions are just plain silly for the fact that only two people may live in them. 10 bedrooms and 20 bathrooms, I guess they can't walk a few more feet to get to the bathroom and must be playing musical rooms so their other half can't find them!
My original design for my 6 1/2 cone driver does go lower than what your friends speakers are capable of but it comes at a cost. One I have only about 86db efficiency@ 1 watt and many would freak out if they saw the VAS number which requires a large box for tuning. I am using a 1 1/3 cubic foot enclosure with this cone driver in a ported enclosure.
I am a bit behind on the conversation so I am trying to see who said what. Whoever said that they disagreed with Richard about the boundary changing the crossover slope, I would have to agree with that, the in-room measured response may change but the slope of the real output from the speaker at crossover isn't truly shifting, those are boundary induced measurement changes at the measurement position.
I think perhaps it was Max who put up this paper, if it was thank you for that reference, if it is someone else thank you instead.
Henri Korhola
Perceptual Study of Loudspeaker Crossover Filters
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A good approach.
SY did a hollow-state preamp for driving a Pass unity-gain power amp iirc, described in an article in aXp some years ago.
Keith O. Johnson used to run preamp signals on 300 ohm twinlead across the room to drive his powered speakers, but I think he attenuated things a bit at the power amplifiers, as I recall he said the twinlead voltage swings were in the neighborhood of a hundred volts or more. No shielding required 🙂
Oliver and Cage is very good, albeit a trifle dated now. I liked the part about characterizing systems using ~non-disruptive (pseudo) random noise in particular. Another good thing to read if one is concerned about there being something special about a noise signal versus a deterministic one.
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Just a note, no more. In 1945, after WW2, Belgrade was practically devastated from the war American carpet bombing, I read somewhete that 71% of all buildings were severly damaged to almost knocked down. This caused the authorities, obviously with a low budget, to choose to build small apartments, as they could fit more of them into any bulding. The pressure was very high, Belgrade had some 350.000 inhabitants in 1041, and today it has more than 2 million. And it's still chronically short of living quarters, although of course muh less than before, but the real estate prices are like you wouldn't believe.
My condo was built in 1961, so it was still made under pressure.
Pavel,
In my slightly larger systems we use an amplifier voltage gain of 20. This allows precise setting of compressors and limiters to protect the loudspeaker systems. As some of the larger amplifiers can deliver well in excess of 150 volts RMS we can't get away with a gain of one.
Now around here the electrical codes require compliance if the voltage goes above 70.7 volts RMS no matter what the current. So as long as you stay below 625 watts into 8 ohms your method meets code.
One fellow who took on maintenance of an early system decided that was wrong and removing the gain setting switches in the amplifiers jumped them all to maximum gain. Just about ruined the system. Mostly because on that setting the amplifiers were designed to deliver full power at 1.4 volts RMS input. So the woofer amplifiers had more gain than the midrange or high frequency units.
In my slightly larger systems we use an amplifier voltage gain of 20. This allows precise setting of compressors and limiters to protect the loudspeaker systems. As some of the larger amplifiers can deliver well in excess of 150 volts RMS we can't get away with a gain of one.
Now around here the electrical codes require compliance if the voltage goes above 70.7 volts RMS no matter what the current. So as long as you stay below 625 watts into 8 ohms your method meets code.
One fellow who took on maintenance of an early system decided that was wrong and removing the gain setting switches in the amplifiers jumped them all to maximum gain. Just about ruined the system. Mostly because on that setting the amplifiers were designed to deliver full power at 1.4 volts RMS input. So the woofer amplifiers had more gain than the midrange or high frequency units.
dvv,
I can tell you that my friends who have moved out of California generally don't return. The cost for a living space is just to much, many are paying close to 1/2 of their income just for their place of living, it is crazy and more people moving here all the time. Apartment costs are through the roof and climbing all the time. Besides Hawaii and New York City there isn't much in the country that is so out of balance in costs as it is to now live in California. Forget about San Francisco, there with the dotcom money it is absolutely insane the prices to just have a place to put your head down at night. I feel your pain.
I can tell you that my friends who have moved out of California generally don't return. The cost for a living space is just to much, many are paying close to 1/2 of their income just for their place of living, it is crazy and more people moving here all the time. Apartment costs are through the roof and climbing all the time. Besides Hawaii and New York City there isn't much in the country that is so out of balance in costs as it is to now live in California. Forget about San Francisco, there with the dotcom money it is absolutely insane the prices to just have a place to put your head down at night. I feel your pain.
RNM,
The first DIY RTA was in Popular Electronics September 1979. It was a kit. The unit is still in production but no longer a kit as the Goldline ASA10B.
N.B. RTA stands for Real Time Analyzer. The heterodyne analyzers are not real time. They are swept to get a frequency response. The FFT analyzers can be used but with difficulties. Typically they are measuring constant bandwidth so they would have to be used with white noise. This can be overcome with a bit of software, but then only slightly fancier is to use a dual FFT and compare the signal source to the measured output. This is known as Source Independent Measurement or S.I.M.
So the first RTA's were multiple filter based, the earliest used LC filters and the display was a CRT using a multiplexer to show all the filters.
ES
The first DIY RTA was in Popular Electronics September 1979. It was a kit. The unit is still in production but no longer a kit as the Goldline ASA10B.
N.B. RTA stands for Real Time Analyzer. The heterodyne analyzers are not real time. They are swept to get a frequency response. The FFT analyzers can be used but with difficulties. Typically they are measuring constant bandwidth so they would have to be used with white noise. This can be overcome with a bit of software, but then only slightly fancier is to use a dual FFT and compare the signal source to the measured output. This is known as Source Independent Measurement or S.I.M.
So the first RTA's were multiple filter based, the earliest used LC filters and the display was a CRT using a multiplexer to show all the filters.
ES
Kindhornman, actually I am VERY comfy in my past and present apartment, despite the fact that it is small. I have lived in it since 1961. My late dad and I wreaked out every single inch of storage space, so it can handle way more than a stock apartment with added cupboards.
My room has one wall covered in natural wood, and at right angles with it, another wall with large windows and protective cotton curtains wall to wall. In addition, my cieling is also covered by natural wood, and the floor with a thick Turkish carpet. Hence, no prallel surfaces to speak of, the room is pretty silent (acoustically passive), no ringing anywhere. This is all great news for my speakers. No pain, all gain, so I'm not complaining, most people in my country can only dream of living in their own, 100% privately owned apartments, my wife and I and our son lives by himself.
In a sense, I wouldn't be too far off if I claimed to live in an acoustically very favorable room.
My room has one wall covered in natural wood, and at right angles with it, another wall with large windows and protective cotton curtains wall to wall. In addition, my cieling is also covered by natural wood, and the floor with a thick Turkish carpet. Hence, no prallel surfaces to speak of, the room is pretty silent (acoustically passive), no ringing anywhere. This is all great news for my speakers. No pain, all gain, so I'm not complaining, most people in my country can only dream of living in their own, 100% privately owned apartments, my wife and I and our son lives by himself.
In a sense, I wouldn't be too far off if I claimed to live in an acoustically very favorable room.
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Well, you just need to look at the total numbers first. You describe exceptions and not average home living room size....
Meanwhile, have you measured the slope of a bass driver in a box with a low pass filter both in a anechoic chamber, room and near multiple surfaces to say the slope does not change?
THx-RNMarsh
Yeah, I have to use at least one hundred amplifiers to get it loud enough. Really!
http://www.seattletimes.com/sports/uw-husky-football/renovated-husky-stadium-earns-raves-from-fans/
Richard,
I know you understand that the actual electrical filter can't be changed by position of the enclosure, that is fixed. Now if you place the speaker against a wall or put in on top of a mixing desk in a studio the balance may change due to reflections but how are you equating the change in measured acoustical response to a change in the filter slope? Generally you are going to see a difference in the bass response due to loading by a surface that is close enough to help the coupling of the driver at low frequencies, and even a change in balance due to a first reflection, but I just see no reason to expect the crossover slope to change.
ps. I have no access to a chamber, only ground plane measurements when that is appropriate.
I know you understand that the actual electrical filter can't be changed by position of the enclosure, that is fixed. Now if you place the speaker against a wall or put in on top of a mixing desk in a studio the balance may change due to reflections but how are you equating the change in measured acoustical response to a change in the filter slope? Generally you are going to see a difference in the bass response due to loading by a surface that is close enough to help the coupling of the driver at low frequencies, and even a change in balance due to a first reflection, but I just see no reason to expect the crossover slope to change.
ps. I have no access to a chamber, only ground plane measurements when that is appropriate.
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(one would be inclined to assume that wealth is measured by the number of toilet seats)
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