Looking at the picture from start of thread...I think I would mount a baffle/devider at the end of the hornpath, so that the two hornpaths doesnt meet untill they leave the box
Further I am certain that some things could be done to the box on the OUTSIDE, making the outside prolonging more effective and achieve better coupling to outside surroundings
Further I am certain that some things could be done to the box on the OUTSIDE, making the outside prolonging more effective and achieve better coupling to outside surroundings
GM said:
Ah, I see. As I stated, I disagree with that model. I believe there's at least 2.25 meters in that horn, and possibly a good deal more.
I really should type the entire article through Google translate again (and save it, this time...) and read the full text again. As far as I know, it doesn't mention the aimed for flare rate, or intended pathlength/mouthsize.
This horn comes from a time when standard exponential and quarter wavelength was the norm (I think), so by determing some parameters, we can hopefully extrapolate the rest. Throatsize is around 400 cm^2, I guesstimate length at 2.25-2.75m and mouthsize as is around 3700 cm^2. The article suggests doubling of mouthsize through floorfiring (BDEAP similarity), which would suggest 7400 cm^2. With that throat, 2.6m length and a 7400 cm^2 mouth, that's roughly a 30 Hz horn. In Hornresp, it sims to 40 Hz with a variety of drivers.
Now, being perfectly realistic, it could also be a 2.25m horn with a 3700 cm^2 mouth (sims to 45 Hz). Those are more or less the extremes of my assessment. Not too shabby for a visually small cabinet.
So far, my Eminence Kappa 12 doesn't sim badly in "my" Rt2.
Regrettably, the original magazine articles do not say anything about the exponential or moth area calculations and compromises, i.e. the theoretical deductions behind the horn is not quantified in any way..
The only thing to go by is that the horn was designed to cover the 30- to 300Hz range, and Fo is at one place referred to as being 30Hz.
Regarding the connection between the main closed volume and the triangular "foot", I've been wondering about this my self.
I've been thinking that perhaps this would act as some sort of Helhmoltz resonator or something, but i can only speculate. There is certainly no specific reference to this in the article..
Who Knows, perhaps I'll do a translation from Swedish to English of these articles if I have some spare time on my hands one day?
The only thing to go by is that the horn was designed to cover the 30- to 300Hz range, and Fo is at one place referred to as being 30Hz.
Regarding the connection between the main closed volume and the triangular "foot", I've been wondering about this my self.
I've been thinking that perhaps this would act as some sort of Helhmoltz resonator or something, but i can only speculate. There is certainly no specific reference to this in the article..
Who Knows, perhaps I'll do a translation from Swedish to English of these articles if I have some spare time on my hands one day?
Hi
About the duct/port,
The RT-2 horn has the same inner height (300mm) as the old horn, RT-1 which had 10" driver. For a 12" to fit RT-2 the designer let the baffle go through to meet the outside of the bottom, by doing this they gained another 19mm in excess of 300mm, just about enough for 12" drivers to fit.
To cover the necessary rectangular cutout one small piece of hatch would be needed.
Allow me to speculate,
Later on during the RT-2 design the author discovered that a foot in form of triangle could be fitted in the bottom instead of the hatch. A triangular shaped section would have dual purposes, a more optimal last horn section and an additional rear chamber.
Now, the narrow slot will form as a port at some frequency. At low frequency the two chambers will be seen as one higher up we will come to resonance, higher up the second box will be disconnected. At a quick guess, the transaction frequency would be about 140Hz.
About the duct/port,
The RT-2 horn has the same inner height (300mm) as the old horn, RT-1 which had 10" driver. For a 12" to fit RT-2 the designer let the baffle go through to meet the outside of the bottom, by doing this they gained another 19mm in excess of 300mm, just about enough for 12" drivers to fit.
To cover the necessary rectangular cutout one small piece of hatch would be needed.
Allow me to speculate,
Later on during the RT-2 design the author discovered that a foot in form of triangle could be fitted in the bottom instead of the hatch. A triangular shaped section would have dual purposes, a more optimal last horn section and an additional rear chamber.
Now, the narrow slot will form as a port at some frequency. At low frequency the two chambers will be seen as one higher up we will come to resonance, higher up the second box will be disconnected. At a quick guess, the transaction frequency would be about 140Hz.
jbell said:
To this day, I will never understand why people insist on stating this. Unless you are using seriously inferior equipment with seriously limited BW, that above statement is far from the truth and you have absolutely no clue what you're missing out on.
I have plenty, PLENTY, PLENTY of recordings with more than enough sub-40Hz information in them. Not just pipe organ recordings and movies either. I'm talking about just about any kind of music imaginable. Jazz, blues, rock, heavy metal, classical, orchestral, easy listening (elevator music), pop, indie rock, Yanni.... I can go on and on and on. Just about all of them will have some form of sub-40Hz information on them.
On any given type of music, I would have to say there' s about a 70:30 ratio of sub-40Hz information in it. The 30% being sub-40Hz.
I challenge anybody to take whatever music CD they want, demo it on a system that only plays flat to 40Hz, then play that same CD on a system that plays flat to 20Hz or lower, then sit there and tell me "If you are listening to music, you don't need below 40hz, period". I always have and always will call this out as total BS.
Sorry for the rant. Just wanted to make my point.
You are welcome to your rant.. no worries there. However, I'd like to know the math behind your rant, and what notes you are missing?
Yes, I'm a geek, AND a musician. (one of my degree's is in music) I've played BBb clarinet, and contra-bassoon, so I know something about low frequency instruments. (Low-A bari-sax is still my favorite.... bassie rocks!!!)
What specific note are you referring to below 40hz? The 27.5 low A on a piano that is the lowest identifiable tone, or the lower overstrung bosendorfer strings?
A couple things to consider. ANY string, produces roughly 10db more volume at the first harmonic, than it does at it's fundamental. So a 40hz open E, is producing 10db more 80hz, than 40hz. Couple that with the equal loudness curves http://en.wikipedia.org/wiki/Equal-loudness_contour and you find out that what you are hearing, is not really 40hz after all, and when it gets to 20hz... it's even more exaggerated. A 60-80db concert setting needs 100-110db 20hz to be heard 'equal loudness' of the very moderate 60-80spl notes that are higher in pitch.
Here's some good reading on pitch, and low frequencies. And keep in mind, these were for pitches that were of 'equal loudness' and you see peoples ability to discern 27.5 hz at next to nothing, even with the severe boost in spl.
http://www.psych.ryerson.ca/russo/Frank A. Russo, Ph.D._files/07-Cuddy_Russo_Galembo.pdf
I'm very accurate on my music, and my music reproduction systems. Those systems should reproduce the ORIGINAL music, not create things that weren't there before. In that intent, below 40hz is not necessary, as the 'notes' are just not there in 95% of music...
Now, if you are a pipe organ music person... I take it all back. 16hz rules... It's not a note, but it WILL take your breath away.
http://en.wikipedia.org/wiki/Symphony_No._3_(Saint-Saëns)
Yes, I'm a geek, AND a musician. (one of my degree's is in music) I've played BBb clarinet, and contra-bassoon, so I know something about low frequency instruments. (Low-A bari-sax is still my favorite.... bassie rocks!!!)
What specific note are you referring to below 40hz? The 27.5 low A on a piano that is the lowest identifiable tone, or the lower overstrung bosendorfer strings?
A couple things to consider. ANY string, produces roughly 10db more volume at the first harmonic, than it does at it's fundamental. So a 40hz open E, is producing 10db more 80hz, than 40hz. Couple that with the equal loudness curves http://en.wikipedia.org/wiki/Equal-loudness_contour and you find out that what you are hearing, is not really 40hz after all, and when it gets to 20hz... it's even more exaggerated. A 60-80db concert setting needs 100-110db 20hz to be heard 'equal loudness' of the very moderate 60-80spl notes that are higher in pitch.
Here's some good reading on pitch, and low frequencies. And keep in mind, these were for pitches that were of 'equal loudness' and you see peoples ability to discern 27.5 hz at next to nothing, even with the severe boost in spl.
http://www.psych.ryerson.ca/russo/Frank A. Russo, Ph.D._files/07-Cuddy_Russo_Galembo.pdf
I'm very accurate on my music, and my music reproduction systems. Those systems should reproduce the ORIGINAL music, not create things that weren't there before. In that intent, below 40hz is not necessary, as the 'notes' are just not there in 95% of music...
Now, if you are a pipe organ music person... I take it all back. 16hz rules... It's not a note, but it WILL take your breath away.
http://en.wikipedia.org/wiki/Symphony_No._3_(Saint-Saëns)
chops, I thought you had gone fullrange, and didnt care much about that down low any more
jbell, as I understand it, whats below say the 40hz you relate to, its mostly related to "room-information", which does enhance ambience and soundstage...if sub is working properly, and im not thinking about those "house-wrecker" subs
jbell, as I understand it, whats below say the 40hz you relate to, its mostly related to "room-information", which does enhance ambience and soundstage...if sub is working properly, and im not thinking about those "house-wrecker" subs
jbell said:
Hmm, the fundamentals are there unless intentionally edited out, ditto sub-harmonics, so while they may not be audible per se they do 'fill out'/enrich/enhance, etc., their harmonic structure, bringing the music closer to 'live'. Our ability to 'fill in the blanks' from its harmonic structure is an OK substitute, but no replacement for the 'real deal', at least to all the folks like me that kept looking for the low cut-of point of diminishing returns as wider BW reproduction became available over the decades until now its down/up to ~8/20 kHz, making multiple driver IBs the only semi-practical solution down low.
So yeah, the pioneers of human hearing research (also sound recording, reproduction) concluded that due to how we perceive sound a ~50-11 kHz BW was all that was required to reproduce a vocal group or orchestra 'full', 'true' enough, so this has remained the standard in most prosound apps until fairly recently.
For an increasing number of HIFI/HT aficionados though, 'close, but no cigar'.
GM
I hear ya' GM...
unfortunately, I've seen just enough studio to know where all that stuff comes from. Most studios have no acoustic per se, and it's all manufactured stuff.. Hate that... So most of what's 'down there' is either mistake, or engineer having fun artificially, not music.
Even my own church (that I got the privilege of designing) can't reproduce 16hz electronically, I had to settle for 25... and I don't know that an A0 has ever been played in church. Although I can tell you the natural acoustic is wonderful.
btw -- for people looking for what low really is... try this for reference.
http://www.contrabass.com/pages/frequency.html
Or check out what trinity used....
http://www.definitivetech.com/Products/products.aspx?path=Subwoofers&productid=SuperCube Trinity
my apologies... now look who's ranting...
I do believe my original statement stands... for 95% of music, there's no 'music' below 40hz.
unfortunately, I've seen just enough studio to know where all that stuff comes from. Most studios have no acoustic per se, and it's all manufactured stuff.. Hate that... So most of what's 'down there' is either mistake, or engineer having fun artificially, not music.
Even my own church (that I got the privilege of designing) can't reproduce 16hz electronically, I had to settle for 25... and I don't know that an A0 has ever been played in church. Although I can tell you the natural acoustic is wonderful.
btw -- for people looking for what low really is... try this for reference.
http://www.contrabass.com/pages/frequency.html
Or check out what trinity used....
http://www.definitivetech.com/Products/products.aspx?path=Subwoofers&productid=SuperCube Trinity
my apologies... now look who's ranting...
I do believe my original statement stands... for 95% of music, there's no 'music' below 40hz.
jbell, maybe 95% of the music YOU listen to doesn't have any information below 40hz, but for the rest of us, especially me, there's tons of music I listen to with REAL bass information below 40hz, not made-up bass in my head.
I too am a musician. I played string bass for 6 years straight, 5 of which I was 1st chair. I also have a 5-string electric bass, can play violin, viola, cello as well as any keyboard instrument. Also, I was just talking with the conductor of our city's symphony orchestra the other day, and he wants me to come play for them as my old music teacher back in the day is their music director and recommended me!
Our orchestra back in school (it was a performing arts school) was a 110 piece orchestra, so I am well aware of what instruments produce what kinds of bass. The city's symphony orchestra is 80 members strong now, maybe soon to be 81 strong.
And yes, I am also a "pipe organ person", and we all know there's some organs out there that put out some seriously low bass, some all the way down to 8Hz, but there's only two of them in the world capable of that.
tinitus, I have gone fullrange, but that doesn't mean I won't be using a couple of bass augmentation units and/or subwoofers along with the fullrangers to get me down below 20Hz.
And you hit it on the head as far as systems that are able to properly reproduce truly low bass frequencies enhancing the ambiance and sound stage of a given venue. It all plays a major roll in the overall sound reproduction to be as accurate as possible.
GM, thank you. Your input just helped me prove my point that much more.
All I have to say is whoever says music doesn't have anything below 40Hz is flat-out fooling themselves.
I too am a musician. I played string bass for 6 years straight, 5 of which I was 1st chair. I also have a 5-string electric bass, can play violin, viola, cello as well as any keyboard instrument. Also, I was just talking with the conductor of our city's symphony orchestra the other day, and he wants me to come play for them as my old music teacher back in the day is their music director and recommended me!
Our orchestra back in school (it was a performing arts school) was a 110 piece orchestra, so I am well aware of what instruments produce what kinds of bass. The city's symphony orchestra is 80 members strong now, maybe soon to be 81 strong.
And yes, I am also a "pipe organ person", and we all know there's some organs out there that put out some seriously low bass, some all the way down to 8Hz, but there's only two of them in the world capable of that.
tinitus, I have gone fullrange, but that doesn't mean I won't be using a couple of bass augmentation units and/or subwoofers along with the fullrangers to get me down below 20Hz.
And you hit it on the head as far as systems that are able to properly reproduce truly low bass frequencies enhancing the ambiance and sound stage of a given venue. It all plays a major roll in the overall sound reproduction to be as accurate as possible.
GM, thank you. Your input just helped me prove my point that much more.
All I have to say is whoever says music doesn't have anything below 40Hz is flat-out fooling themselves.
All:
no offense meant, and none taken. Yes, perspective is really key -- isn't it?
I'll argue that a 60hz w-bin is as much of an abomination to sound, as is trying to find 15hz in vinyl for dnb. The w-bin can't reproduce the real low bass in music faithfully, and the 15hz is an artifact of the recording process. Both (in my limited opinion) are not part of the original music.
I suppose much of my bent on flat to 40hz, comes from the artificial recording process, and all of the after the fact 'engineering' that I have really come to dislike. Live sound (in my case -- jazz and orchestral) is one of life's true enjoyments. In those cases, natural acoustic of a fantastic hall, a bosendorfer 290, etc... are true enjoyments. I sing baritone, and have been clocked at 113db before. You are correct, the harmonics, and sub harmonics, when energized in a great hall, are quite something. Unfortunately 'natural' recordings of music with truly great low bass from a 'venue' as you say, falls into the 5% category. 95% or more, are studio... Way too few great recordings. Wish there were more. Yes below 40hz is in music, and is musical -- I don't deny that. It's just not common.
As I'm a fan of great music and great music recordings, maybe I can be pointed to some great "natural" recordings with 20hz bass.. (with tef, smaart, etc.. analysis to show it's there) My church system is flat to 25.. (at least smaart says it is) I just don't see it showing up on a regular basis.
Also: Elbert -- apologies for the thread hijack. I know this has nothing to do with getting your horn to do what you want.
no offense meant, and none taken. Yes, perspective is really key -- isn't it?
I'll argue that a 60hz w-bin is as much of an abomination to sound, as is trying to find 15hz in vinyl for dnb. The w-bin can't reproduce the real low bass in music faithfully, and the 15hz is an artifact of the recording process. Both (in my limited opinion) are not part of the original music.
I suppose much of my bent on flat to 40hz, comes from the artificial recording process, and all of the after the fact 'engineering' that I have really come to dislike. Live sound (in my case -- jazz and orchestral) is one of life's true enjoyments. In those cases, natural acoustic of a fantastic hall, a bosendorfer 290, etc... are true enjoyments. I sing baritone, and have been clocked at 113db before. You are correct, the harmonics, and sub harmonics, when energized in a great hall, are quite something. Unfortunately 'natural' recordings of music with truly great low bass from a 'venue' as you say, falls into the 5% category. 95% or more, are studio... Way too few great recordings. Wish there were more. Yes below 40hz is in music, and is musical -- I don't deny that. It's just not common.
As I'm a fan of great music and great music recordings, maybe I can be pointed to some great "natural" recordings with 20hz bass.. (with tef, smaart, etc.. analysis to show it's there) My church system is flat to 25.. (at least smaart says it is) I just don't see it showing up on a regular basis.
Also: Elbert -- apologies for the thread hijack. I know this has nothing to do with getting your horn to do what you want.
Good to see some discussion about the ends here, not just the means!
Looks like I'm drawing nearer and nearer to the end of my search for a suitable driver solution to the horn..
The only thing I've found so far that clearly surpasses (seemingly) the performance potential of the old SEAS 13" I've temporarily installed, is a pair of new SEAS CA26RE4X woofers...
But this is not by much, and the price of these two new drivers would be considerable..
Enclosed is a plot of showing the dual SEAS 10" alternative superimposed in grey above the black curve of the SEAS 13", both driven to Xmax.
The dual 10" option is only a few dB above the 13" which also has signs of a very modest dip around 60Hz.
As my stereo speakers, one of which has temporarily donated its 13" woofer to the horn are some 31 year old kit-speakers which are not to exciting anyway, the best option is probably to take them out of service and use the 13" woofers for the horn (one in spare).
Then I can spend the money building a good set of stereo speakers in stead!
Looks like I'm drawing nearer and nearer to the end of my search for a suitable driver solution to the horn..
The only thing I've found so far that clearly surpasses (seemingly) the performance potential of the old SEAS 13" I've temporarily installed, is a pair of new SEAS CA26RE4X woofers...
But this is not by much, and the price of these two new drivers would be considerable..
Enclosed is a plot of showing the dual SEAS 10" alternative superimposed in grey above the black curve of the SEAS 13", both driven to Xmax.
The dual 10" option is only a few dB above the 13" which also has signs of a very modest dip around 60Hz.
As my stereo speakers, one of which has temporarily donated its 13" woofer to the horn are some 31 year old kit-speakers which are not to exciting anyway, the best option is probably to take them out of service and use the 13" woofers for the horn (one in spare).
Then I can spend the money building a good set of stereo speakers in stead!
Attachments
Hi,
the 7dB/oct slope from 80Hz down to 40Hz will make these seem bass light.
The 11dB/oct slope from 40Hz down to 20Hz will sound like it is removing all the very low bass notes and no sub-bass to speak of.
I found that a 3dB/oct slope over two octaves sounded very nice, i.e. 25Hz 6dB below 100Hz. and 20Hz just 10dB below 100Hz.
the 7dB/oct slope from 80Hz down to 40Hz will make these seem bass light.
The 11dB/oct slope from 40Hz down to 20Hz will sound like it is removing all the very low bass notes and no sub-bass to speak of.
I found that a 3dB/oct slope over two octaves sounded very nice, i.e. 25Hz 6dB below 100Hz. and 20Hz just 10dB below 100Hz.
Elbert said:
As my stereo speakers, one of which has temporarily donated its 13" woofer to the horn are some 31 year old kit-speakers which are not to exciting anyway, the best option is probably to take them out of service and use the 13" woofers for the horn (one in spare).
Then I can spend the money building a good set of stereo speakers in stead!
That has crossed my mind too, but dare not say...whether it would be better put the effort into your mains...it makes sense
Besides, in most of your sims I dont see much difference between the various drivers, other than different output
It has also been stated several times that those sims doesnt tell the whole truth
You have experienced a substantial improvement with your old 13" Seas, and probably cant reasonably expect any better than that...proven in real
True true, as discussed earlier, these sims don't show the whole trught, and there is certainly more low end response in my livingroom than what the sims indicate..
True, there is a slope to the response curve, but not so bad that some moderate EQ can give good results. This is again where dynamic headroom come in to the picture, with 114 dB uncorrected at 40 Hz Xlin, one can EQ quite a lot and still play at respectable levlels.
And that's where the SEAS 33F-WB seems to excell..
All woofers I came across with low Fs and good Xlin, had high moving mass and low Vas, inevitably giving a very rippled response in the sims.
And those few woofers I found with low Mms and high Vas had limited Xmax, typically around the 3mm mark.
The seas seems to have all the right stuff.. plus an unsurpassed Xlin of 7mm. I also tried simulations with the other 13" seas woofers, none seemed that good and they only had a Xlin of 5mm.
Strange to think that the first driver I tried after the ill-chosen delta-pros were to be so spot on!
well, at least i considered (a lot) of the alternatives, and If I go for the SEAS 13" woofers, I guess I can do so with a certain confidence that I didn't exactly overlook any obvious and superior alternatives..
Looks like the money is going in to a decent side system..
True, there is a slope to the response curve, but not so bad that some moderate EQ can give good results. This is again where dynamic headroom come in to the picture, with 114 dB uncorrected at 40 Hz Xlin, one can EQ quite a lot and still play at respectable levlels.
And that's where the SEAS 33F-WB seems to excell..
All woofers I came across with low Fs and good Xlin, had high moving mass and low Vas, inevitably giving a very rippled response in the sims.
And those few woofers I found with low Mms and high Vas had limited Xmax, typically around the 3mm mark.
The seas seems to have all the right stuff.. plus an unsurpassed Xlin of 7mm. I also tried simulations with the other 13" seas woofers, none seemed that good and they only had a Xlin of 5mm.
Strange to think that the first driver I tried after the ill-chosen delta-pros were to be so spot on!
well, at least i considered (a lot) of the alternatives, and If I go for the SEAS 13" woofers, I guess I can do so with a certain confidence that I didn't exactly overlook any obvious and superior alternatives..
Looks like the money is going in to a decent side system..
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