I like bass, I run my sub probably 10 - 20 db hotter than the mains (I just got my fancy new measurement mic so i should probably measure it sometime). It doesn't require any fancy electronics, in fact at the moment I'm just using an AVR out (with it's 100 hz 12 db/oct built in sub filter IIRC) going into a car audio crossover which adds an extra 12 db/oct low pass at 60 hz. (This works just fine until I figure out what kind of mini dsp I want to buy, probably the cheap $100 one if it can do delay).
The sub out from the car audio crossover feeds into my Behringer EP4000. So boosting the bass is as simple as turning up the sub amp. For "regular" music I don't even turn the sub on. For classic rock and electronic type stuff, I want to feel the bass so I run it way hotter than the mains.
I'm probably limited to 110 - 120 db right now with my very modest system (the speakers and subs cost me a total of $80 - the Heresys were free and i built the tapped horn with cheap wood and a second hand but new driver at about 1/4 retail price). I always want more, I'm sure if I could do 150 db I would (below 60 hz at least, not in the mids or highs). I like bass.
Of course most of my listening is night time easy listening at probably 60 - 70 db - I leave it on all night lately.
The sub out from the car audio crossover feeds into my Behringer EP4000. So boosting the bass is as simple as turning up the sub amp. For "regular" music I don't even turn the sub on. For classic rock and electronic type stuff, I want to feel the bass so I run it way hotter than the mains.
I'm probably limited to 110 - 120 db right now with my very modest system (the speakers and subs cost me a total of $80 - the Heresys were free and i built the tapped horn with cheap wood and a second hand but new driver at about 1/4 retail price). I always want more, I'm sure if I could do 150 db I would (below 60 hz at least, not in the mids or highs). I like bass.
Of course most of my listening is night time easy listening at probably 60 - 70 db - I leave it on all night lately.
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Thanks for mentioning the dbx box.
Although establishing the correct correction is very contentious despite the superficial logical appeal of the Fletcher-Munson-type data*, there is no problem creating any curve you like to any degree of precision, analogly (4 pot vc) or digitally.
The problem is analogous to "gain management", just like with digital/analog hybrid systems. Unless it tested a mic at your chair, no device knows how loud the sound is at your ears. Adding "warmth" is a snap; adding it wisely is harder.
Alas, poverty and having my automotive enthusiasms more directed to motorcycles these last 55 seasons, I haven't owned all the fine cars you mercilessly chide me about. Sorry to say, I've only owned a Jaguar (in the golden age), Alfa, Lotus, and Maserati, and various family buses. I know that doesn't compare to the fine cars you've had extended driving experience with.... or maybe just read about in magazines.
Ben
*Remember the El Greco fallacy? Do we want to hear a singer as if she is two feet tall and standing next to us or as if she is singing from 50 feet away?
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Hi Y'all,
You are a prolific bunch. 🙂
Art: Thanks for the clarifications. As I never listen to music that loud anymore, I keep on forgetting about overloading mikes, etc..
As to barn doors: It might make sense to keep the upper edge of the horn lower than a square mouth would indicate, and go w/ a rectangular mouth. The barn doors could then be the front doors to close up the horn when not in use, rolled out left and right. The reason I mentioned LeCleac`h horns is that his method of extending the horn mouth makes sense to me (built-in barn doors-go ahead: shoot me). I have neither had the time nor the funding to experiment w/ anything but my old Altec 511B horns (well, there are a few others on the shelf, JBLs, Cobraflex...), and they sound better when mounted to a solid surface...so, maybe the barn doors can be the used to support the sound coming from the left and right speakers too? Once entropy455 decides on the final parameters, and locations, all that can be worked out. I still feel it would be a shame to go all out on the subwoofer horn, and then to compromise on where the music actually comes from; I vote for a full horn system, no compromise horns.
My first car was a 1951 VW bug, its little engine didn't have 25Hp, but I would trade all I have to be back in it in 1965.
Regards,
You are a prolific bunch. 🙂
Art: Thanks for the clarifications. As I never listen to music that loud anymore, I keep on forgetting about overloading mikes, etc..
As to barn doors: It might make sense to keep the upper edge of the horn lower than a square mouth would indicate, and go w/ a rectangular mouth. The barn doors could then be the front doors to close up the horn when not in use, rolled out left and right. The reason I mentioned LeCleac`h horns is that his method of extending the horn mouth makes sense to me (built-in barn doors-go ahead: shoot me). I have neither had the time nor the funding to experiment w/ anything but my old Altec 511B horns (well, there are a few others on the shelf, JBLs, Cobraflex...), and they sound better when mounted to a solid surface...so, maybe the barn doors can be the used to support the sound coming from the left and right speakers too? Once entropy455 decides on the final parameters, and locations, all that can be worked out. I still feel it would be a shame to go all out on the subwoofer horn, and then to compromise on where the music actually comes from; I vote for a full horn system, no compromise horns.
My first car was a 1951 VW bug, its little engine didn't have 25Hp, but I would trade all I have to be back in it in 1965.
Regards,
Eric,
A solid vertical wall boundary will definitely increase forward output and reduce rear output from the horn.
My boundary tests which were done with a variety of loudspeakers (BR, FLH and TH) all were done with the boundary in the horizontal plane. In each case, with the LF corner varying by nearly an octave (60 Hz to 35 Hz) the LF output was increased by 3 dB when the frontal area was doubled. JAG seems to doubt my results, perhaps he should do some measurements himself to determine if the program he is using is correct, he already knows Hornresp conflicts with it.
I did not specifically test boundary addition in the vertical plane, as it is problematic to implement, and often not practical due to covering the top speakers, but using a wall above the sub as a "soffit" for the top speakers would be an excellent choice, eliminating edge diffraction, as well as "beefing up" the upper bass range so important to get the chest pounding kick you seem to enjoy.
There are a number of us dinosaur era sound engineers that have not fully embraced the changes in sound systems, which have "evolved" into bass monsters with plenty of pants leg fluttering bass with little "punch".
A typical "big bottom" system will have end fire bass arrays four 2x18" cabinets deep and 4 to 10 wide, both stage left and right, and a cardioid configuration of subs the width of the stage, lower row pointing forward, upper row pointed rearward, with a third forward row on top if the stage is 6' rather than 4' high. With 104 to 200 (or more) 18" woofers in end fire/cardioid configuration, their rear output is attenuated, but the forward output is largely diffracting around and reflecting off the cabinets in front of them. Because of the near field diffraction/reflection "feature", they sound poor if crossed above 60-80 Hz, so everything above that range is often covered by a skinny front-loaded hanging line above, which has virtually no horizontal control in the 60 to 120 Hz "kick" range, often resulting in a bloated "woof".
You will often find dinosaur era sound engineers behind the desk at shows that still provide a "punchy" bottom, they still remember the sound that a lot of the new generations of engineers starting after the mid 1990s have simply not experienced, and are still able to get it by careful use of whatever system they use- Dave Rat used to use two line hangs per side for RHCH, separating his choice of instrumentation and vocals between the two, before upgrading to a newer generation of Vdosc with enough headroom (and expense…) to not require that implementation any more.
If you implement a low-mid system capable of the dynamic range and pattern control of your bass horn, it will be capable of the kind of "kick" seldom heard at most concerts in the decades since vertical line arrays have become almost the exclusive choice of touring rock shows.
Art
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You are not paying attention again. Very early in this thread I said I simulated your barn door tests and the sims matched your measurements.
I also just got done telling you why you got the results you did - you started out with a vertical array of tiny speakers that were way too small on their own to provide any diffraction gains at the bottom of the passband. Tripling the frontal boundary area allowed for significant gain down to the bottom of the passband because you lowest frequency was pretty high.
The diffraction spreadsheet is known to produce accurate results. Jeff Bagby regularly produces speakers even for commercial vendors and he always shows his design sims and measurement of the finished products. And the measurements always overlay the design sims almost exactly. Hundreds of people use his spreadsheets to design speakers, thousands of speakers have been designed and built using them.
If you don't trust this software you can use a different diffraction simulator, The Edge is also free.
Hornresp is not a diffraction simulator. There's no way to tell Hornresp what the baffle dimensions are and it always assumes the baffle face is round and only as large as the port/terminus/mouth so how could it possibly even try to simulate diffraction?
The fact that you don't seem to even know the basics of diffraction is pretty alarming.
Oliver,
Mounting the left/right mains on rolling "barn doors" is a fabulous idea, and would allow listening to a monster stereo inside the horn/bomb shelter when closed!
My first car was 1970 VW Squareback with no heat whatsoever due to the heat exchangers being completely rusted through. I wouldn't trade anything to be back in that car in the Minnesota winter of 1975, the biting cold, pushing and pulling two "aftermarket" chokes to start it, and crushing off two fingers and half my thumb are memories better forgot. That said, in spite of the ridiculous inflation from the mid 70s through the mid 1980s, it was a great time for music and sound!
Today is even better for music, one can have centuries of music from thousands of artists available from a postage size device. There is no way I could have fit that much content in my VW, even if it was filled completely full of cassette tapes.
Some of those live cassette tapes have made it to my digital archives, and still evoke strong memories of the beginning of the end of the analog era.
OK, my birthday is over, I'll try to cut down the nostalgia factory output for the rest of the year 😉
Art
JAG,
You simulated one of my tests, out of dozens that I have not spent the time writing up. Glad your sims verified my measurements.
You could verify, or find my statements are incorrect with your own actual measurements in far less time than you have spent lamenting my "alarming" mental condition in your repetitive trolling posts.
Cheers,
Art
Every one of my posts contains actual technical information. Just because I'm correcting you when you make mistakes doesn't mean I'm trolling.
Interesting thread, even the offtopic stuff about electricity grids, electric cars etc.... 😀
I'm looking forward to eventually seeing pictures of the actual build! 😎
It appears that OP is still somewhat confused about SPL definitions, how they translate to "loudness", and how much "dB's" he "needs", as evident in the following conflicting statements:
Talking about dB's is always confusing especially when people don't specify what type of dB's: SPL peak (self-explanatory i suppose) or SPL Leq (averaged, long term equivalent Level), and maybe added to that a frequency weighting like A- or C-scale.
Leq, LAeq - Equivalent Sound Level : Definition, Terms, Units, Measurement - Acoustic Glossary
Leq, LAeq, Equivalent Continuous Sound Level : The Sound and Vibration Hire and Calibration Specialists
Consider that by nature, music signals consist of a long series of peaks (transient events) and following resonance and decay. The difference in level between the peaks and the average signal energy level is called crest factor. Depending on the style and how it has been produced (acoustic recording without dynamic range manipulation vs fully ITB computer produced with virtual instruments and loads of compression) , music may have a crest factor between >20 dB (acoustic music) and 3 dB (Skrillex, Metallica 😀). Anything less than 10 dB will start to sound progressively horrible.
In fact you can never accurately describe sound levels with a single number. To really know what's going on you need to look at both the average and peak levels. Lets assume chili peppers have 15 dB crest factor. If you listen at 85 dB SPL continuous (Leq), the peaks of the music will be actually at 100 dB SPL!!
And then you need to factor in listening distance, as has been pointed out multiple times. So to achieve 85 dB SPL continuous/average, 100 dB peak (=assuming 15 dB crest factor) at 10 m, your system needs to have 120 dB peak output capability .
85 dB average would be elevated living room listening level loudness . 95 dB average is roughly what you have in a full bar on friday night at 11 pm 😀
Above 100 dB average is club/concert territory, above 110 dB average typically in the front row at large concerts/outdoor festivals. Add to that 10 -20 dB crest factor depending on the music for the transient peaks.
Just based on the premise of being a 40 - 60 ft full size bass horn with a giant mouth, aiming for anything less than (rock) concert level with low distortion @ 1 meter would be a complete waste, as has been pointed out before. If you design and build this properly, and load it with sufficient displacement capacity (25 kW of B&C like you suggested will do), it will have the potential of being VERY loud up close should you choose to turn up the volume (140 - 150 dB peak).
I think one of the goals in this project should be to get the horn bandwidth to go up high enough to cover midbass/"kick" frequencies up to atleast ~150 Hz. Then you could get away with crossing over directly into some horn-loaded 12" mids (e.g. DJK double 12" mantarays, or something fancier like Peter Morris DIY tops
).
I would suggest suspending the tops at least 3 - 5 meters high to get even SPL coverage without too much front-to back variation in your listening area (building a support structure for that should be easy with your skills and machinery 😀)
Depending on your overall system design choices you will have no problem to entertain/"cover" at least 200 - 500 people at rock concert levels.
PS: a final thought: Why not design the structure so that it can be used as a stage for a band? 😎
PPS: also consider this while going ahead with your giant stereo.... https://bobmccarthy.wordpress.com/2011/03/09/the-emperors-new-stereo/ 😉
I'm looking forward to eventually seeing pictures of the actual build! 😎
It appears that OP is still somewhat confused about SPL definitions, how they translate to "loudness", and how much "dB's" he "needs", as evident in the following conflicting statements:
Talking about dB's is always confusing especially when people don't specify what type of dB's: SPL peak (self-explanatory i suppose) or SPL Leq (averaged, long term equivalent Level), and maybe added to that a frequency weighting like A- or C-scale.
Leq, LAeq - Equivalent Sound Level : Definition, Terms, Units, Measurement - Acoustic Glossary
Leq, LAeq, Equivalent Continuous Sound Level : The Sound and Vibration Hire and Calibration Specialists
Consider that by nature, music signals consist of a long series of peaks (transient events) and following resonance and decay. The difference in level between the peaks and the average signal energy level is called crest factor. Depending on the style and how it has been produced (acoustic recording without dynamic range manipulation vs fully ITB computer produced with virtual instruments and loads of compression) , music may have a crest factor between >20 dB (acoustic music) and 3 dB (Skrillex, Metallica 😀). Anything less than 10 dB will start to sound progressively horrible.
In fact you can never accurately describe sound levels with a single number. To really know what's going on you need to look at both the average and peak levels. Lets assume chili peppers have 15 dB crest factor. If you listen at 85 dB SPL continuous (Leq), the peaks of the music will be actually at 100 dB SPL!!
And then you need to factor in listening distance, as has been pointed out multiple times. So to achieve 85 dB SPL continuous/average, 100 dB peak (=assuming 15 dB crest factor) at 10 m, your system needs to have 120 dB peak output capability .
85 dB average would be elevated living room listening level loudness . 95 dB average is roughly what you have in a full bar on friday night at 11 pm 😀
Above 100 dB average is club/concert territory, above 110 dB average typically in the front row at large concerts/outdoor festivals. Add to that 10 -20 dB crest factor depending on the music for the transient peaks.
Just based on the premise of being a 40 - 60 ft full size bass horn with a giant mouth, aiming for anything less than (rock) concert level with low distortion @ 1 meter would be a complete waste, as has been pointed out before. If you design and build this properly, and load it with sufficient displacement capacity (25 kW of B&C like you suggested will do), it will have the potential of being VERY loud up close should you choose to turn up the volume (140 - 150 dB peak).
I think one of the goals in this project should be to get the horn bandwidth to go up high enough to cover midbass/"kick" frequencies up to atleast ~150 Hz. Then you could get away with crossing over directly into some horn-loaded 12" mids (e.g. DJK double 12" mantarays, or something fancier like Peter Morris DIY tops
).I would suggest suspending the tops at least 3 - 5 meters high to get even SPL coverage without too much front-to back variation in your listening area (building a support structure for that should be easy with your skills and machinery 😀)
Depending on your overall system design choices you will have no problem to entertain/"cover" at least 200 - 500 people at rock concert levels.
PS: a final thought: Why not design the structure so that it can be used as a stage for a band? 😎
PPS: also consider this while going ahead with your giant stereo.... https://bobmccarthy.wordpress.com/2011/03/09/the-emperors-new-stereo/ 😉
You have shown a singular pressure result and without knowing the power distribution it is difficult to discern the rolloff/bumps.
How does the barn door sim do when the ground is included?
Right underneath the part of the spreadsheet that I showed is the boundary simulator. It's a quick download and super simple to use, check it out.
The ground is already included in the Hornresp sim though if you sim in 2 pi, you don't want to include it twice. But the Hornresp sim does not include diffraction effects. It can't because it doesn't know how big the frontal area is or what shape it is.
The ground is already included in the Hornresp sim though if you sim in 2 pi, you don't want to include it twice. But the Hornresp sim does not include diffraction effects. It can't because it doesn't know how big the frontal area is or what shape it is.
A boundary simulator couldn't accurately simulate a boundary from a pressure measurement when diffraction is present, so I looked at this page and it appears likely that baffle diffraction and directivity from radiator size is taken into account in the boundary simulation, however it probably assumes a baffled plane wavefront as the source whereas the horn in question would have a varying non-plane wavefront shape with frequency that also varies in size at the axial distance represented by the simmed radiator, as well as higher order modes.
Yes, the spreadsheet takes a stab at directivity based on sound source size. The spreadsheet can't possible know what the horn directivity is actually like so it's not a perfect solution but all we're trying to do here is find out how large the wall has to be to provide extra reinforcement at 20 hz where the horn itself has minimal directivity.
I was able to use this spreadsheet to explain why weltersys was getting the extra gain he showed in his barn door measurements, and also to explain how the DSL BC series subs get a bit of gain from their large frontal boundary area.
If you want to get more accurate it is possible but you need to use Akabak, which can simulate the the horn response the horn directivity and the frontal area diffraction all in a single sim but that's a lot more complex sim to script and would take a lot longer. The results this spreadsheet shows are close enough. Weltersys seems to be arguing that relatively tiny barn doors are going to provide a 3 db gain at 20 hz for this example horn, it just isn't going to work like that.
I was able to use this spreadsheet to explain why weltersys was getting the extra gain he showed in his barn door measurements, and also to explain how the DSL BC series subs get a bit of gain from their large frontal boundary area.
If you want to get more accurate it is possible but you need to use Akabak, which can simulate the the horn response the horn directivity and the frontal area diffraction all in a single sim but that's a lot more complex sim to script and would take a lot longer. The results this spreadsheet shows are close enough. Weltersys seems to be arguing that relatively tiny barn doors are going to provide a 3 db gain at 20 hz for this example horn, it just isn't going to work like that.
Yea, it does do delay. Despite the low price, it seems really hard to fault - just get one. Even if you do get a fancier unit later, you'll surely find another use for the $100 unit.
Aww, sweet, thanks for thinking of me 🙂
I haven't got a lot to add about sims: the OP is a smart guy and can run his own (also: JAG vs. Art are doing a better job of arguing about the applicability of sims than I could).
I did provide a bit more personal, practical info: another link to an existing system with a pair of bass concrete horns, plus a few contributions about the purely physical stuff of working with concrete. The OP didn't respond to that and has his own plans for how to do the concrete, which is fine by me: anything that actually works is fine by me.
JAG, you must have thought some of my suggestions were OK, because you essentially echoed them (posts 203 and 212):
The average commute is the task of shifting 50-100 kg of meat from one suburb to another, 20km away. A bicycle can do that with ~100 watts from the "engine".
Most people, most of the time, are applying a lot more power than is needed for the task.
The average car needs 70 horsepower because of our expectations, and because the average vehicle weighs about 20 times the weight of the payload.
How about
(4) They weigh at least double what the original electric cars did.
(5) They are trying to compete in a market that wants the ability to go at 200 km/h (when most commutes happen at 1/5 this speed)
e.g. If you plonked the lithium-ion battery of the Nissan Leaf into a 1908 Fritchle (10 horsepower), that ye-olde vehicle would have a range of about 650 km (400 miles).
If we're getting speculative (about "magically" converting things):
When self-driving cars are the norm, we won't worry about power and top speeds anymore - if you're blogging or reading a good book during the journey, and the total commute time is about the same as it used to be, you just won't care.
A minimalist velomobile, which is essentially bicycle tech + a streamlined shell, will do 45-50 kph with 200 watts (assuming level terrain etc).
1000 Watts would presumably be enough for a more roomy self-driving equivalent, to whisk me to work (while lying back and reading a book).
250 million self-driving velomobiles like this would, >90% of the time, be a better than adequate replacement for the USA's cars, and could be charged simply off household solar.
And they can look pretty cool 🙂
https://en.wikipedia.org/wiki/Fantom
As quite a number posts have gone OT, i thought i'd jump in too !
I heard about a kangaroo that fell out of a tree & landed on a duck. Now what the kangaroo was doing up a tree i don't know, but anyways. The duck just happended to be passing underneath, chasing a snake that had been trying to steal the ducks eggs. What that has to do with anything, i don't know either 😀
*
Re solar panels
Various new methods that increase output are on the way, which should reach 20 + % in the next few years. Interestingly 40% has been available for decades, it's what satellites etc use ! We are not allowed to have it though 😡 If they had & didmass produced them, the price would have come right down for everyone, years ago !
I heard about a kangaroo that fell out of a tree & landed on a duck. Now what the kangaroo was doing up a tree i don't know, but anyways. The duck just happended to be passing underneath, chasing a snake that had been trying to steal the ducks eggs. What that has to do with anything, i don't know either 😀
*
Re solar panels
Various new methods that increase output are on the way, which should reach 20 + % in the next few years. Interestingly 40% has been available for decades, it's what satellites etc use ! We are not allowed to have it though 😡 If they had & didmass produced them, the price would have come right down for everyone, years ago !
Just like that carburetor invented in the 70s that made cars get 100 mpg – and the oil companies purchased & buried the patent. . . Right. . . . . FWIW - large broadcast satellites are nuclear powered (decay heat thermocouple). Even in space, there’s that pesky problem of solar panels not working at night. . . .
Self-driving cars are about ten years too soon (the control processors are not powerful enough). My prediction: wrongful death lawsuits will strike this industry dead before it ever takes off.
A gasoline scooter sporting an impressive 70 miles per gallon, is still putting 5 horsepower to the road at 30 mph. The point? 1000 Watts is 1.34 horsepower. That is not going to happen EVER on any freeway, with any vehicle. . . . You know as well as I, that people are not going to purchase featherweight deathtrap cars – if you could even call them cars at that point. . . . And people are not going to tolerate electric vehicles going 30 mph on the freeway, when gasoline cars are trying to go 75 mph. . . Just like solar power – the only reason we have electric cars on the market today, is because of HEAVY government subsidies. Stop the flow of tax dollars, and electric cars will disappear faster than a sunset. If this industry had any future, it would already be turning a profit & generating tax dollars - not consuming them. . . .
Power conversion is not speculative, or magical – 500 square meters of 15% efficient solar cells, on a bright sunny day (1000 watt solar flux), will quite literally output 75 kW – which is 100 horsepower (when feed into a 100% efficient electric motor) thus with a “real” electric motor, it’s not even 100 horsepower (as delivered to the road, where it counts).
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Just based on the premise of being a 40 - 60 ft full size bass horn with a giant mouth, aiming for anything less than (rock) concert level with low distortion @ 1 meter would be a complete waste, as has been pointed out before. If you design and build this properly, and load it with sufficient displacement capacity (25 kW of B&C like you suggested will do), it will have the potential of being VERY loud up close should you choose to turn up the volume (140 - 150 dB peak).
I think one of the goals in this project should be to get the horn bandwidth to go up high enough to cover midbass/"kick" frequencies up to atleast ~150 Hz. Then you could get away with crossing over directly into some horn-loaded 12" mids (e.g. DJK double 12" mantarays, or something fancier like Peter Morris DIY tops
I would suggest suspending the tops at least 3 - 5 meters high to get even SPL coverage without too much front-to back variation in your listening area (building a support structure for that should be easy with your skills and machinery 😀)
I agree - if I do this, I should go all out. . . . . A full-size bass-horn is pointless, without a significant “wow” factor. (even my wife agrees with you - and others who have recommended pumping more air. . .) Thus I will reevaluate my selection for bass-horn driver & driver quantities.
If this were true, the Chinese would be flooding the market with 40% efficient solar panels. Or said another way, the profit-potential is simply too large to suppress the technology. . . .
Toyota has spent upwards of 100 million dollars in R&D on the Prius - to get 45 mpg out of a car that would otherwise get 39. . . . Do you think that the Toyota Engineers simply failed to consider installing solar panels?