Since this has already been covered I will repeat - NO. If this was even close to true headphones wouldn't work at frequencies below a few khz. It's going to sound best BY FAR standing inside the horn mouth. The only thing you gain (actually lose) by standing far away is a 6 db decline in spl per doubling of distance.
Let's talk about gasifiers now.
Please don't misunderstand. I'm not implying that you cant hear a 30 Hz sound when standing 10 feet from a driver.
What was explained to me, is that you can hear a difference in the sound fidelity, at the transition point between wave loading, and wave propagation - as a function of distance between your ears and the horns.
Specific example: if you stand back 50 Hz (22.6 feet from the horn mouth), the bass drum and bass guitar (frequencies below 50 Hz) will not sound as "clean" as if you're standing 20 Hz back. I was told that as you walk around, the phenomenon is very pronounced, and the system sounds best when you are back at least one full wavelength of the lowest reproduced system frequency. (he actually recommended 1.5 wavelengths - specifically stating the more, the better). . . .
What was explained to me, is that you can hear a difference in the sound fidelity, at the transition point between wave loading, and wave propagation - as a function of distance between your ears and the horns.
Specific example: if you stand back 50 Hz (22.6 feet from the horn mouth), the bass drum and bass guitar (frequencies below 50 Hz) will not sound as "clean" as if you're standing 20 Hz back. I was told that as you walk around, the phenomenon is very pronounced, and the system sounds best when you are back at least one full wavelength of the lowest reproduced system frequency. (he actually recommended 1.5 wavelengths - specifically stating the more, the better). . . .
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Consider a wave-generating swimming pool (like at the big waterparks).
Picture swimming right up next to the wall that's generating the wave. Something wavelike is happening - you're bobbing up & down (and hopefully not get sucked into a cyclical pressure chamber). however the "action" adjacent to the wall is not a complete wave - it's still forming (wave loading).
Does this have a noticeable impact on system fidelity? I don't know. I've been told it does. . . . In that you don't want to swim next to the wall. . . . If awarded the option, you want to be completely in the 'wave propagation' region. . . . .
Picture swimming right up next to the wall that's generating the wave. Something wavelike is happening - you're bobbing up & down (and hopefully not get sucked into a cyclical pressure chamber). however the "action" adjacent to the wall is not a complete wave - it's still forming (wave loading).
Does this have a noticeable impact on system fidelity? I don't know. I've been told it does. . . . In that you don't want to swim next to the wall. . . . If awarded the option, you want to be completely in the 'wave propagation' region. . . . .
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Hi Entropy455,
Post #340: "...my wife asked me this morning if we’d really have to sit back a full wavelength from the bass horn, to have it sound good. I’ve been told (by the only person I’ve met who’s actually heard full-size outdoor horns) that the answer is absolutely yes...."
I have never heard a full size bass horn similar to what you are suggesting. I would be surprised, that the region of conversion from in-horn transmission to in-air wave propagation requires a full wavelength. My guess would be that should happen much more quickly, e.g.: @ 15Hz you would be looking @ >23m, that's just way more than listening to indoor horns, and other sound sources, would make me believe. There is a region in front of a horn where the sound does not seem to have fully 'integrated', this should happen within a few meters, let's say 2m-5m. What should help is using barn doors as e.g.: side reflectors.
The much bigger problem I see is the integration of the complete sound system. You are looking at a four way system of horns, all these outputs have to come together.
There are a lot of guys here that could provide a lot more insight here, would be great if we would hear from some of them (Welter, Danley, Geddes, Kolbrek, McBean.....). 🙂 I'll attach a discussion...
Regards,
P.S.: You don't like Willie - sacrilege.
Post #340: "...my wife asked me this morning if we’d really have to sit back a full wavelength from the bass horn, to have it sound good. I’ve been told (by the only person I’ve met who’s actually heard full-size outdoor horns) that the answer is absolutely yes...."
I have never heard a full size bass horn similar to what you are suggesting. I would be surprised, that the region of conversion from in-horn transmission to in-air wave propagation requires a full wavelength. My guess would be that should happen much more quickly, e.g.: @ 15Hz you would be looking @ >23m, that's just way more than listening to indoor horns, and other sound sources, would make me believe. There is a region in front of a horn where the sound does not seem to have fully 'integrated', this should happen within a few meters, let's say 2m-5m. What should help is using barn doors as e.g.: side reflectors.
The much bigger problem I see is the integration of the complete sound system. You are looking at a four way system of horns, all these outputs have to come together.
There are a lot of guys here that could provide a lot more insight here, would be great if we would hear from some of them (Welter, Danley, Geddes, Kolbrek, McBean.....). 🙂 I'll attach a discussion...
Regards,
P.S.: You don't like Willie - sacrilege.
Attachments
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Your specific example is from a person who is experiencing the problems of room modes, nodes and low frequency comb filtering, all of which are absent when using a single LF point source in an outdoor environment free of reflective surfaces.
Your shop building's proximity to your planned horn position will to some degree make your exterior environment behave somewhat like an interior, but having experienced the sound of large horns of every conceivable (and some inconceivably stupid) design outdoors, I can assure you that they simply are louder the nearer you are to the mouth.
That said, as you approach the "mouth wave bubble", which could be depicted or imagined like a bubble emerging from a blow-tube, once you are within the area defined by the spherical encapsulation of the "tube" (the horn mouth, and any boundary supporting it's wave propagation) the SPL will no longer increase with the inverse distance. Then, as you step inside the horn, SPL again increases at a very close approximation of what is expected from the inverse distance law.
Going back to your comments on subjects also near and dear to me (thermodynamics and machine design) on the topic of electricity & efficiency, I have built several electric powered vehicles (three-wheeled, two wheeled and single screw boat) over the last three decades, and though I won't argue with your estimation of 70 horsepower for an average car at freeway speeds is OK, my trike, using an order of magnitude less power (.8 HP) was capable of 30MPH on flat roads.
Using a "100 watt" solar panel (wattage is dependent on insolation) to charge the 3 group 27 lead acid batteries (an order of magnitude more subject to the Peukert's "puke out" effect, and far heavier than recent battery innovations) my trike never had to be plugged in to the AC grid.
Sound systems that are playing dynamic music sources (10dB or greater crest factor) using 80% efficient amplifiers use only a bit more than 10% of the peak power, so if you have a 110 dB one watt, one meter system, average power consumption is only a bit more than 100 milliwatts at what Toronto Ben calls "ear damaging levels" that can be supported by tiny solar cells, batteries and inverters.
JAG, don't know if Harbor Freight has made it to Ontario, but I have purchased a 2000/4000 watt continuous/peak 12V/120VAC inverter from them for $125 USD that out-performs the old school transformer based technology costing 16 times more in every measurable metric .
High frequency switching power supplies have revolutionized inverter and amplifier industry, using far less material for far more output potential. High frequency switching now allows DC power from "conventional" or alternative sources to be transmitted further than Tesla's 3 phase transformer based transmission for a fraction of the cost, Edison would have won the AC/DC war had it been available back in the day.
High frequency switching systems now available would permit long-range transmission of power around a world-wide grid, allowing locally available intermittent supplies of wind, hydro, and solar energy to be used at distant locations, eliminating the need for expensive energy storage devices, eliminating the need to use progressively more expensive petrochemical and nuclear based energy for our needs.
But that ain't going to happen in a word run by "leaders" bent on protecting the borders that would have to be "breached" by HF/HV voltage lines. That said, by integrating another of Tesla's innovations, wireless power transmission, that "bump in the road" could be eliminated, though would then be bogged down by complaints that it will cause cancer in the state of Red Hot Chile Pepper's "Californication".
Art (wished STS would have got the RHCP account back in the day) Welter
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I don't think there's any Harbor Freight here, our equivalent place is Princess Auto. I haven't checked there but even Home Depot has cheap inverters, here's a 4000/8000 sustained/peak unit for only $649 - https://www.homedepot.ca/en/home/p.12v-4000-watt-power-inverter.1000682141.html
Let me list the problems with something like this -
1. I need to wire it right into my home electrical panel, if I do that with this thing and my house burns down I don't think insurance will be very sympathetic.
2. I'd like 120/240V so I can use 240V appliances like an oven, and I'd like to keep the system simple as possible, so no dual separate +120V and -120V inverters if possible.
3. I'd like the battery bank to be a high voltage so cabling costs are minimized. These cheap things never come any bigger than 12VDC.
4. I'd like to be able to plug a generator right into the inverter to charge the batteries - this is an option I probably wouldn't use, and it's probably not an efficient way to do it, but if the main charging system goes down and I need to run a temporary generator this will allow any generator to fill in just by plugging a backup generator into the inverter.
5. I'd like pure sine wave, not modified sine wave output. Not sure how important this really is but I've seen the comparison videos with light bulbs and motors running hot and humming when using the modified sine wave.
So this product solves all of those problems. It's meant to be wired into a home electrical panel, it's 120/240VAC, 48VDC, accepts generator plugged right into it to charge the battery bank, and it's pure sine wave. Also, if it's not enough power you can parallel up to 4 units for 4x more power. But it is costly, a couple thousand dollars. This is 4000 watt and that's probably peak.
Magnum Energy MS4448PAE Inverter - Wholesale Solar
You can also buy an entire "power center", the inverter is the heart but also included are digital displays (power input and output), battery charge controller, safety breakers and stuff like that. I'm not sure how much value the "power center" would add, but if it saves a couple hours of electrician's time it might be worth it. And let's not kid ourselves here, even if I wire it all up myself there's going to be a hefty electrician's bill just for his stamp of approval if I want my house insurance to be valid.
http://www.wholesalesolar.com/prewired-solar-power-centers
I'm still in the researching costs phase of the project though, so I'm not 100 percent convinced that I need a $2000 inverter yet, but I'm pretty sure I do.
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As shown in attachments 1 and 2.
Attachment 3 shows the power response with an input voltage Eg of 6.32 volts, equivalent to 5 watts into a nominal 8 ohm load.
Attachments
Except that in the case of the bass horn, there is no net gas flow. A Saturn V bass horn will never get you to the moon 🙂.
Many thanks for replying.
Right, as I said, 5 watts will destroy the hearing of everybody in the house with 120 dB. So OP better not buy an amp capable of more than 4 watts or maybe less.
(Before having fantasies (and sims) about how loud your home HiFi needs to be, best to check out your current loudest sessions with an SPL meter. You might be surprised how few dB are running around.)
But being a Mac person since 1984 April, your HornResp parameter attachment doesn't mean much to me, other than the conventional T/S numbers. It would be great to port it to Mac, eh.
Ben
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Glad to see one more person is thinking in terms of system design - long overdue. My expectation is that the horn and the rest of the system will be fairly separate architecturally. The giant horn can go where it can, assuming a sharp slope crossover and minimal harmonic distortion to "give away" the location of the bass source. Then the upper range can be located where it make sense in terms of the room layout. Works fine as you'll hear from a lot of people currently experimenting with sub and multi-sub locations.
BTW, the photo of that gorgeous horn system in a handsome living room provides an interesting cautionary tale.
What we see is a room with almost no absorbent, at least in the picture. The sound there would be horrible and unlistenable although with the directional benefits of a horn, maybe a bit less horrible than with direct radiators. The attractive modern decor probably resembles the rooms of a lot of folks on this forum... and nobody has wall-to-wall carpeting these days.
So it takes more that just thinking about a good suspension to make good sound.
The odd thing is that a true horn make real good theoretical sense for bass where you are playing across the driver resonance (they make practical sense too, but you have to own a lot of earth moving equipment).
But there's no problem producing good sound north of the bass by any number of means - providing only that you don't use a box that spoils the sound. Other than some tweeters where wee horns/waveguides can be very helpful, not sure there're many enthusiasts who advocate for middle range horns.
Ben
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"much more than 100 horsepower" to run the heater as well? 😱 😱 I thought you said you understood this stuff? 😀
200-400Hz is not a good place to be sitting in a null, even a small one. Horses for courses, it's a hard range to deal with.
Ok, I suppose I wouldn't be so quick to write off bass directionality based on the multi-sub approach, there are subtle differences.
Ben,
You continue to repeat that 120 dB "will destroy the hearing of everybody in the house", even though the statement is false in regards to low frequency sound. If it were true, there wouldn't be any helicoptor pilots with normal hearing, and no astronauts could hear either, as they are subjected to LF noise approaching 160 dB on every launch.
The suggestions for the OP to take his wife's bass rig outside, and measure SPL at a distance near enough to be loud enough for his taste would be useful in determining the scale of the project.
I've been a Mac person since around 1985, but being able to use Hornresp (and the London Architect software needed to program a BSS BLU 100 DSP) made me purchase a used Windoze machine to operate it. You can get used PCs that will run the compact Hornresp program for literally nothing, as the bloated software popular today won't even run on the older machines, causing them to be discarded, or donated to thrift stores where they can be picked up for a few dollars.
I'm on the fence about ever purchasing another Mac now, as they now routinely throw their expensive software "under the bus" by not providing backward compatibility with their new processors and software. I'm still using a 2006 year old MacBook for audio testing, because my 2012 iMac won't properly operate SMAART. The $700 Mac "Logic" program (like ProTools for Mac) won't support the MIDI function on either machine since I was forced to "upgrade" the OS for other programs I use more frequently.
Art
JAG,
The newer "modified sine wave" have so many "steps" that the output is virtually the same as true sine waves. Older converters had so few steps that the lower frequency DC "clunks" in the output would cause problems with all sorts of equipment.
The cheap inverter purchased a few years ago from Harbor Freight 120V output power is dead clean with audio gear, while some of my older units make a slight buzzing sound on some audio gear with poor power supply designs, and tube gear.
Most of my solar installation and repair work was done in New Mexico, providing power for houses that were located off the electrical grid. For those houses, the availability of sunlight for long periods almost every day of the year made the installations very cost effective, compared to the expense of extending the grid. Still, solar was too expensive for cooking or heating, other than small power devices like a microwave oven, coffee machine, or toaster. The off-grid houses always used a combination of passive solar and gas heat during the winter.
As my dad (r.i.p.) used to say "The only problem with "free energy" is it is so damn expensive". If you are already on the grid, his saying is still pretty much 100% correct.
I had considered a solar installation, but without the tax incentives, which required making a lot more money than I do to use, it was simply not cost effective. The return on investment, including the income from selling surplus power back to the local power company would have been nearly at the half-life of the solar panels. Though the high grade panels could be expected to last several decades longer after ROI had been reached, they would be putting out progressively less power per square meter than what will be available in the future, for less money. As it turned out, since I moved from New Mexico, I would really have been hurting if I had done the solar installation, as virtually no buyer would have wanted to pay the cost of an expensive, redundant power system.
Since most of the "heavy lifting" has already been done in the PV panel field, other than a slight improvement in cost per watt, we probably won't see more than very moderate increases in efficiency in the next few decades. For northern locations like Ontario, the amount of sunlight available requires so many more panels than in ideal places like New Mexico that a solar installation makes even less sense there if you are already on the electrical grid.
That said, for applications like the OP, a solar system could actually be cheaper than running permitted AC power to the distant location, especially if the power it would make was used for other applications when not being used for music.
Art
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Eric,
In post #345 I wrote:
"Your specific example is from a person who is experiencing the problems of room modes, nodes and low frequency comb filtering, all of which are absent when using a single LF point source in an outdoor environment free of reflective surfaces."
After further consideration, another aspect of large horns that could explain the "specific example" described is the progressively narrowing pattern at upper frequencies of a bass horn. If the horn is located on the ground, it will sound "less clean" in the near field if you stand near it than further away, as you are out of the upper pattern when near, but in the pattern when on axis 56.5 feet/18.3 meter/20Hz wavelength back.
Art
Too bad your wisdom is quite wide of accepted standards.
In any case, the "120" (or 140 or whatever, since I too do not think these standards are trustworthy esp as applied to motorcyclists, ahem, ahem). My wry amp figure relates to the ideal horn McBean modelled although you seem to be surprised to learn that I wasn't all too serious about suggesting the OP start looking around for a 4 watt amp.
But compared to the out-of-this-world amp recommendations you see on this forum all the time, I would say 50 clean watts makes for a really loud true horn. Once again, that should illustrate for people how unsmart non-horn systems are.
B.
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While I don't doubt this at all it can be hard to know what you are getting before you buy. And I absolutely need an inverter that won't void my insurance. All the serious off grid systems seem to sell pure wave inverters. They do cost more but the list of features is a lot more impressive than the cheap units too.
I agree that off grid can be expensive. Here's a 4kw package that provides 525 kwh/month for about $10000.
The Homestead 3.96 kW 12-Panel Suniva Off-Grid Solar System - Wholesale Solar
But I don't need most of the stuff on that list, I certainly don't need the solar panels. All I need are batteries and an inverter.
Here's a more detailed spec sheet for the inverter I was talking about, I was wrong, this is 4000 watts sustained, not peak and it can do 8500 watts for 5 seconds. There's a nice video explaining the wiring and features on this page too.
https://www.altestore.com/store/inv...pae-4448-4400-watt-48v-invertercharger-p8110/
This thing has a charge controller built in (I assume the only battery charging input is the AC generator input though). So in addition to this inverter I just need batteries, a couple of breakers and some wiring. Maybe $5000 USD total.
My electric bills are somewhere between $2500 - $4000 annually. So the system could easily pay for itself in two years.
I already have a generator and I already have unlimited amounts of smoke from my boiler to feed the generator (gasification).
If there's anyone not familiar with gasification, it's pretty simple. Here's a good video showing an implementation of the FEMA gasifier and as an extra bonus he's showing it running a generator. (FEMA made publicly available plans a few decades ago for emergency power gasifiers.) This implementation is quite a bit smaller and also a lot more complex than what I need. Since I already have the smoke all I need to do is filter it and pipe it into the generator which eliminates most of the parts in this video.
https://www.youtube.com/watch?v=a6e3CprVTi8
If I can make a gasifier fueled generator powering an inverter and battery bank for under $5000 and if it lasts 20 years the return on investment will be massive.
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Also I forgot to mention that a 4000 watt inverter should be able to safely power all the big stuff - central air conditioning, full size stove and oven, clothes dryer, etc. Just not all at the same time, and there's no reason to simultaneously operate all the big ticket items at the same time anyway. It just requires a bit of planning and energy conservation.
This inverter also has a remote generator auto on / shut off trigger signal too, so if I decide to upgrade my generator one day to a model that can accept the on/off trigger from the inverter the whole system would be almost completely self operating and as efficient as possible.
This inverter also has a remote generator auto on / shut off trigger signal too, so if I decide to upgrade my generator one day to a model that can accept the on/off trigger from the inverter the whole system would be almost completely self operating and as efficient as possible.
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