Andy,
I wasn't accurate enough in what i wrote. I should have stated it's a worst case scenario from the point of power requirement in that with wide dynamic range material ( which in my view is a good things if the genre of music require it) this requirements are the most demanding/severe/worst.
I think most amateurs doesn't get the studio systems aren't operated full open gain 95% of the time. That said for the 5% when you need an accurate reproduction of what you track at 'realistic' level (to assess choices to be made during production) you really need the system to be able to deliver ( when a drumer have to check his take just after playing it and he insist to listen at same level he performed- no need to say i just used hear protection or leaved the room in my days in studio!).
More people should stay just behind an irritated drumer for just a song. Then imagine how loud have to be a loudspeaker system to reproduce this at 3/4 meters distance. The requirements are huge ( for efficiency and power to drive).
Of course it can be seen as a waste as this is not used this much but rather think of headroom gain. It garantee that the system will mitigate issues about power compression, dynamic ( if there is still in the message) won't be compomised by the loudspeakers on lower dynamic range material. Overall it will increase the sense of ease in the reproduction.
3m to 3,5m is what i've seen the most in professional control room from 70's to 90's. This ask for big rooms. I've been in one place ( early 90's designed iirc) where the system had 4m distancebut the room was huge ( a place where international famous artists were common customers).
Since 2000 control room size never seems to stop decreasing ( same trend as the amount of money imparted to production).
And i share your view.
But keep in mind i'm an happy few who doesn't have to take into account waf or neighbours... which helps to have 'big' box ( the down side of it to me).
I wasn't accurate enough in what i wrote. I should have stated it's a worst case scenario from the point of power requirement in that with wide dynamic range material ( which in my view is a good things if the genre of music require it) this requirements are the most demanding/severe/worst.
I think most amateurs doesn't get the studio systems aren't operated full open gain 95% of the time. That said for the 5% when you need an accurate reproduction of what you track at 'realistic' level (to assess choices to be made during production) you really need the system to be able to deliver ( when a drumer have to check his take just after playing it and he insist to listen at same level he performed- no need to say i just used hear protection or leaved the room in my days in studio!).
More people should stay just behind an irritated drumer for just a song. Then imagine how loud have to be a loudspeaker system to reproduce this at 3/4 meters distance. The requirements are huge ( for efficiency and power to drive).
Of course it can be seen as a waste as this is not used this much but rather think of headroom gain. It garantee that the system will mitigate issues about power compression, dynamic ( if there is still in the message) won't be compomised by the loudspeakers on lower dynamic range material. Overall it will increase the sense of ease in the reproduction.
3m to 3,5m is what i've seen the most in professional control room from 70's to 90's. This ask for big rooms. I've been in one place ( early 90's designed iirc) where the system had 4m distancebut the room was huge ( a place where international famous artists were common customers).
Since 2000 control room size never seems to stop decreasing ( same trend as the amount of money imparted to production).
And i share your view.
But keep in mind i'm an happy few who doesn't have to take into account waf or neighbours... which helps to have 'big' box ( the down side of it to me).
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I said Pro Audio, not PA. "PA" stands for Public Address, and it generally means sound reinforcement of a live event. PA is all about high SPL and coverage. Low distortion and smooth-flat frequency response are way down on the list of importance. And yes, horns are everywhere in PA systems.
The Quested studio monitor I linked to is rated at 126 dB max SPL @ 1 meter. I don't know what dome tweeter is used, but I suspect it is a ScanSpeak unit. The midrange is definitely the Volt 3" dome unit that is also used in the OSMC.
Hello camplo
How is a horn tuned and why?? That would be the last thing you would want.
I don't see them sharing the characteristics of a reflex/vented box.
Rob 🙂
Hi Jim, please don't take this as me being confrontational...don't mean it that way at all.
Because I've found proaudio PA as in live-sound, to place low distortion, smooth-flat frequency response, time and phase alignment at the top of the list.....along with even coverage to. Really, more so than home audio.
Maximum linear SPL comes next on the list...and i stress linear......
SPL that does not sacrifice any of the former SQ goals.
I'm talking national/international A level performers and their associated PA & engineers. Not Joe blow in the neighbor hood park (although some of these guys are enlightened too.)
Ironically, I find the pragmatic science, constant innovation, and exacting high quality audio demands of the big-dog PA world, to be very refreshing. And probably the best source of education/inspiration for my home audio DIY efforts.
A horn, no less than a transmission line, no less than br is tuned by axial length vs csa
Why is a vent tuned? Strange question...usually because you want loading down to a particular frequency...basically bent tuning controls bandwidth...pretty much the same thing as cutoff but I think cutoff is when you are down -3db or something like that... tuning would be like I said before wherever the vent is the most resonant...take a look at the impedance chart for evidence.
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TL, BR, PS...they take the back wave and work on It, with the exception of bandpass and the'bose cannon' (Double TL). A horn (yes, add BLH to the previous list), a front horn, works with the forward radiation.
Hello camplo
I did not ask why you tune a base reflex. I asked how a horns cut off is equivalent to a bass reflex enclosure. How is a horn tuned.
A bass reflex enclosure is tuned to a specific frequency and the vent acts like a band pass filter. At the tuning frequency cone movement is at a minimum and impedance at the minimum as well.
A FLH has cut off frequency that is defined by the the type of curve used and the size/physical dimensions length width. The cut-off looks like a high pass filter.
Now are these equivalent?? Why would you have a group delay spike @ cutoff??
Cut-off is the low frequency limit not a tuned resonance.
Rob🙂
Those are actually equivalent on a certain level for example a compression driver on the horn is a fourth order bandpass... as you already know a base reflects relies on the helm homes resignation harmonic..... a horn is more like a transmission line which you live on quarter wave tuning...
And all vent designs you'll see a spike in group delay near called off due to the driver seeing the highest air mass a.k.a. loading at that frequency.... it's literally pushing the most air that the volume of air represents a load on the driver which literally causes the driver to lag due to the "mass" (pressure) its seeing.
If you were to put the same type of flare on the port to a bass reflex it will see the same shift in frequency in other words, The literal Axiall length would not represent the tuning as it would if there were no flare...If you were to taper the br port....the tuning note/cutoff would be lower than if a port of the a constant csa port of the same length...basically doing the opposite of a flair in relation to tuning note vs axial length for a line with identical beginning csa...
And all vent designs you'll see a spike in group delay near called off due to the driver seeing the highest air mass a.k.a. loading at that frequency.... it's literally pushing the most air that the volume of air represents a load on the driver which literally causes the driver to lag due to the "mass" (pressure) its seeing.
If you were to put the same type of flare on the port to a bass reflex it will see the same shift in frequency in other words, The literal Axiall length would not represent the tuning as it would if there were no flare...If you were to taper the br port....the tuning note/cutoff would be lower than if a port of the a constant csa port of the same length...basically doing the opposite of a flair in relation to tuning note vs axial length for a line with identical beginning csa...
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It would be interesting to know which designs you are considering to build, and why.
And the 126db is a sum of all the drivers working together. That is a great speaker by the way. Heard it years ago in the late 90's
lol, I don't know if its worth a re- submission lol!
All vents exhibit this trait, a flair (expansion) will raise the tuning as opposed to axial length
A taper will lower the tuning note as opposed to axial length.
I was just reading that conical horns have not a cutoff? BR and TL and FLH horns that I am familiar with (exponential and similar) all do....a Compression driver on a horn is a 4th order bandpass.
At tuning, group delay peaks due to loading of the driver, via max pressure seen as the most air being moved as well as the largest resonate note of the vent....
All the Vents we are speaking exhibit the same unloading of the driver below the cutoff/tuning note, dramatic increase in excursion, and high pass filter type response below cutoff/tuning note.
Most of that should answer
If the vent is constant in CSA with no flare or taper....the major resonance is at 1/4wl looking literally at axial length...usually I play with Hornresp as I answer these types of questions....my laptop is macos. When get into the Helmhotz territory things go differently, I never studied that, so this applies to the longer lines taping into 1/4wl tuning...I had to go downstairs to hornresp so I hope you appreciate this...
What do you call a back loaded horn with no flair....a transmission line.....add a flare to the end of a transmission line..now its a horn? Its all the same physics....Create a back loaded truncated horn, its just a Transmission line with a fancy name and no flair (or a very short flair maybe).
If you are good with words and theory as I am, you'd see that a dynamic driver is also a resonator....
The only thing I can think to correct is that the cutoff can sometimes be various differences below the tuning note? A lot of times it is really close...I think technically the cutoff is the f3 below median FR? Something like that. Tuning note is where youll see the most resonance from the vent....People still use these interchangeable I've seen, though technically incorrect usually they are within a very close proximity depending on the type of vent.
All vents exhibit this trait, a flair (expansion) will raise the tuning as opposed to axial length
A taper will lower the tuning note as opposed to axial length.
I was just reading that conical horns have not a cutoff? BR and TL and FLH horns that I am familiar with (exponential and similar) all do....a Compression driver on a horn is a 4th order bandpass.
At tuning, group delay peaks due to loading of the driver, via max pressure seen as the most air being moved as well as the largest resonate note of the vent....
All the Vents we are speaking exhibit the same unloading of the driver below the cutoff/tuning note, dramatic increase in excursion, and high pass filter type response below cutoff/tuning note.
Most of that should answer
If the vent is constant in CSA with no flare or taper....the major resonance is at 1/4wl looking literally at axial length...usually I play with Hornresp as I answer these types of questions....my laptop is macos. When get into the Helmhotz territory things go differently, I never studied that, so this applies to the longer lines taping into 1/4wl tuning...I had to go downstairs to hornresp so I hope you appreciate this...
What do you call a back loaded horn with no flair....a transmission line.....add a flare to the end of a transmission line..now its a horn? Its all the same physics....Create a back loaded truncated horn, its just a Transmission line with a fancy name and no flair (or a very short flair maybe).
So a transmission line and a horn are both acoustic (impedance) transformers....If I called it a resonator it will still fly....A Br is a helmhotlz resonator....a transmission line and "horn" are a Quarter wave resonator...Final Answer =)
If you are good with words and theory as I am, you'd see that a dynamic driver is also a resonator....
The only thing I can think to correct is that the cutoff can sometimes be various differences below the tuning note? A lot of times it is really close...I think technically the cutoff is the f3 below median FR? Something like that. Tuning note is where youll see the most resonance from the vent....People still use these interchangeable I've seen, though technically incorrect usually they are within a very close proximity depending on the type of vent.
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Sure, I knew when I wrote it that I painted live sound reinforcement with too broad a brush. I am certain if I paid $600 for a seat at a top-tier performance from someone like Eric Clapton or Andrea Bocelli I would have the best sound bestowed upon my ears that is technically possible in such a venue.
But I can not help but think that sound quality available in a top-tier control room or a mastering studio is going to be a step above the "best seat in the house" at a concert... in terms of frequency response, low THD/IMD, low compression, uniformity of direct sound to early reflections to room sound... This is the context I was addressing by pointing out that some of the very best monitoring/mastering speaker systems use direct radiators for mid and high frequencies.
j.
Jim You know my thread....I've studied this topic over the last couple of years, my system is to be a mastering monitor....The stuff they sell the studio guys is a joke. The Strauss mf 2.1 represents a top tier mastering monitor....it might as well be an Altec 2 way....The Jbl M2 is right there with it....Its been said over and over....brand names don't create SQ per say....configurations and driver philosophy does....A two-way with a compression driver and a 15" woofer is literally one of the best all time configurations for SQ....I don't need to pay 64K to Strauss in order to apply common sense to a damn speaker design. The Geddes speaker is what? 10k? I've spent the same on my design.
Studio gear of yesterday had better approach even if the drivers aren't as good as new gen. We here in America will sacrifice SQ for "good enough" in order to save space....its like some type of conspiracy really...once upon a time the products were approached better and consequently bigger ,then they started shrinking everything. Then the dopes missed the SQ only Sd can bring and started adding multiple drivers and expanding vertically....its nuts. We as consumers home and studio alike, have been duped by the loudspeaker industry. As most industry tend to go....they master a product and then place top dollar on the best approach while selling other inferior "top notch" products to the know nots....its strange but true. Show me all the large sd studio monitors...Strauss mf 2.1, Jbl m2, Augsperger....Das bout it...The Volt mid and Atc sm75-150s is a 3"mid in a waveguide, so it has the directivity more of a 6" mid....Show me a studio monitor with a 6" mid on a 3 way....These fools are getting played...and its easy because lack of knowledge of the consumer. The Dutch 8c (heres our 8" mid! Show me another monitor with a 8" dedicated mid) is the most popular studio monitor last checked before getting banned from Fb group Mastering engineers worldwide....That and PMC because lots of people think theres some type of magic there due to the title "transmission line"....The Amphion monitors are really popular too...and its like wow they finally introduced a basic *** waveguide to a tweeter....wait the Macie Hr824 already did and they loved it but didn't know why...Nor did mackie even advertise that the woofer was a motion feedback woofer. Thats neither here nor there...The stuff done on this board with waveguides blows the stuff bought off of shelves out of the water (ok m2 waveguide is a thing). The pioneers got it right a long time ago...The industries are just milking us now...unless you know how to build your own stuff that is.
If you want to get deeper and kinda weird into my conspiracy on this....The loudness war may as well be an unconscious search for lost sound quality...Louder is perceived to be of better SQ, its a known psychological characteristic of the human. If everyone had a 15"with a horn/waveguide in their living room would the overall trend be this super compressed mix/master? Probably not. Its my theory, but it holds water if you ask me. Loudness via compression is an attempt to reach the impact of truly dynamic systems built using sd. Yet we are sold toy (low sd) speakers more or less. In the home and studio.
"the best" says who? Compared to what? Its only the best, because whats truly the best has been removed from comparison...at least thats my theory. Funny enough, my Axi on this 350hz horn has almost identical performance (CSD) to an ATC sm75-150s except for directivity and the Axi doubles as a tweeter, can play lower via large horn, etc, more dynamic ability, what have you.
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