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Way to come full circle guys.... So for Dynamic Radiators, "mouth" diameter aka diaphragm diameter is the main factor for Directivity strength and Depth...but for Horns Mouth size controls depth of Directivity, and wall angle, and axial length govern DI level....
All stuff I know... from conversations had here...but if I get into a jumble again...I might say some things wrong. Mabat led a conversation on the directivity of a horn/waveguides, not that far back in thread...I'll try to stay relevant lol...I just went through another mid design crisis and some late nights...I think I've done that about 3 times now and each time I try to out build what I've created and it is sinking in that I cannot do much better than what I've done here, aiming for my goals.
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Reverse engineering is a personality trait of mine and Its exactly what I've done to design this system so far....
predesign Criteria;
Low XO goal for the tweeter...If you recall I first was on a tangent for horn loaded Amt's and high performance Coaxial's so that I could have a ~150hz XO. Reasoning being, the idea of having an unadulterated midrange through treble, so no axis changes and no filters. I also came up with a theory of burring the XO in the room, not sure if that flies or even matters lol....but detection of distortion seems be worse with lower frequencies so there may be some benefits in that respect. The AXi2050 plus a 150hz is an excellent choice to achieve this goal....show me the cheaper version of this and I'll sell what I got...I had unique expectations that just so happens that only an expensive compression driver was suited for....
High Dynamic Contrast.....I dug into the topic of Dynamic contrast for the better part of 6 months at the beginning of this thread....trying to bridge the gap between subjective and objective....Dynamic contrast is the measure between the lowest recreated sounds and the highest in comparison to the signal.....there is only one right, no different than phase....simply put, Dynamic Contrast, is sort of a misnomer in this field...for Amplitude Distortion....We all know that high dynamic potential of driver and system create the right conditions to provide the least amount of Amplitude Distortion. Keeping excursion under control relates directly to the BL curve and suspension issues and is inherently apart of the formula to avoid Amplitude Distortion. This requires high Sd in order to minimize excursion....essentially I aimed to fit as much Sd into this design as possible before disrupting "homeostasis". Its obvious that I cannot achieve anymore Sd without disrupting parts of criteria already at its max limit, ie, height of baffle has reached the max height I set, and there is no way to can reasonable squeeze in more....The last design I cooked up looked ok until I finally noticed how much sensitivity/efficiency was lost.
IIR filters with low final GroupDelay... In order to keep things low, the right filters and the right combination of filters, need to be used. Not a challenge for FIR but I wanted to get the best GD with IIR, A challenge for a design but when all your Xo's are below ~400-300hz it becomes easier
High Direct Energy...Direct Energy provides a response that is more accurate to the signal....This ensures that my choices made during Sound Design are accurate and translate to other systems...People have many approaches but one thing that is accepted is that a sound engineer can actually get to know how a system is lying and eventually create accurate results to the intended sonic design. Yet if thats possible then I will chose the system that creates the most true to signal experience and move from there. That system, would be one that creates the most direct energy, all things else equal, unless we've created an anechoic like listening room. I essentially seek to drown out the room with direct energy to a certain degree. That also led to a baffle as wide as possible, which somehow I just say'd F'it and now have 32" wide baffles....if you can't flush mount into the wall....bring the wall with you, sort a speak.
Gaudy/Ridiculousness/OvertheTop/Fun... I wanted to buy the drivers that were high performing and a little extra for the ego...It turns out that the Axi was chosen already by necessity so that was solved....The woofers that were sold to me by the forum and so many other DIY folks as some of the best woofers available....Acoustic Elegance....also has a knack for flair....The 18H+ and 15m appear to be designed to mate...its apparent to me by the success I've had within design around the predicted FR. I think I could of designed the same thing with cheaper hand picked woofers but not Compression driver. Sd is Sd and who has more Sd than the Axi and can compete with the SQ for the range and sensitivity achieved. If AE had not of been suggested so many times, I was looking hard at the newly discovered (for me) driver manufacturer from Italy, with great (looking) bang for buck..LaVoce....With likely tolerable sacrifices I think I could have built this same config with cheaper drivers for likely 2500....and when I boast about what we've done here and try to convince more sound engineers to become loudspeaker engineers, I explain that part commonly. Having Gaudy equipment is also fun when you we get into these ******* matches with sound engineers about their gear. Gaudy has a fun factor to it. This has been a "fun" project, not a need. It was just strange that my "Fun" was looking to achieve higher SQ than people who literally need SQ to feed their family.
The group of people here, that have been gracious enough to frequent my thread, have been, not just teachers, but my voice of reason, so that Fun or experimental, did not become, degrading. I stated above, I've had several designer break downs, and so far, have been able to pull together and not go off the deep end, with the design.....I thought I did, for a split second with the horn, until I reminded myself of the 300hz XO. This is a simple build with just a flare of drama via the PPSL but I did manage to get 2560cm2 of Sd into my mains, front baffle, bass channel
(on paper/sim still to be seen in real life via successful XO's)ps- warning, If the wind blows hard enough I could possibly go on a tangent regarding TMMWW with side fire woofers....the only thing stopping me is this idea of direct energy I seem to be chasing....I understand that Direct+Reverb=spl thus more Sd creates higher amounts of Direct energy when facing the listener and the listener is within proximity, but when the woofers are side firing....it doesn't seem right for the goal....then again, Bass is considered apart of the room in so many words? So I'm not certain if it would make a world of diff outside of various cancellations and HF limits, which, direction the bass woofers, are directed. It would seem, if possible, even at low bass....you'd receive more direct energy, even if slightly, with a nearfield proximity of say 24"-36" inches?
Are you guys in the thinking that at low bass, say 100hz and lower, there is no such thing as direct energy? Orrrrrrrrr???? Thoughts?
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I Appreciate that. I was reading that guys thread, here at diya, and starting to question my modelling aspects. I take your word for it because I know you enough to know that you are nowhere interested in anything overkill....also....This system shows 30hz at 129db in eighth space
....just one bass module, within xmax at 20hz. A result of aiming for a standard of 115db/1meter for 30-20khz, within xmax, for mastering monitors, using half space. I am not complaining, only explaining. I am more concerned with how low I can get excursion at normal domestic volumes as should be anyone else claiming to design elite mastering monitors.WRT spreading out the bass sources. I cannot see with sim, how important it is on a horizontal plane but on a vertical plane, a vertical array of woofers seemed to help....and correction from the woofer closest to the floor seemed to be most effective. Long rectangle basement, call one short side, "front". 2 mains up front in the corners and 2 auxiliary boxes behind me, symmetrically if possible. I know that this is not exactly what you do, but for me, I will at least, start experimentation at this point. A configuration that I should be able to imitate, in most Michigan basements, literally every other house is a big long rectangle. In these parts at least...I guess for example Detroit, houses are not of the same architectural persuasion.
What I cant figure just yet:
what is the slope of critical damping, that is, how many decibels/oct
How does one mathematically or practically aim for this with a system in a room. Personally, it would seem that once you have a visual reference of the slope, you could eye it with an eq and rta/measurements
I forgot more Design Criteria!
High SPL, Low Distortion, 2way... I didn't exactly achieve 2 channels....but, I can technically say its a 2 way sitting on top of a "sub" without being "wrong".
The most important take away, I think, being that at least 3 channels are needed to create this experience properly....when we call "proper" Half space simulation. With the criteria that I would like in a mastering monitor, I had already set myself up for aiming for scientific SQ without saying it.
Sealed... I've always had a sort of fetish for powerful sealed bass, at the expense of never experiencing it and the clout of SQ. Now it seems there may be less differences than I thought between vent vs sealed when either are properly applied. There is also the idea that a PPSL is the shortest, offset horn....one could make....basically a 50/50 hybrid lol sealed/vent. I'm ok with that too.
Hybridization is welcome lol....I've got a tweeter mid, a vented sealed bass mid.....an enclosure wall lol.....Loudspeaker/headphone
People like TNT use dialog that wouldn't be used face to face...thats bad energy sorry. Regardless if thats his honest feelings, a pecking order and respect are real things also....that the internet allows one to evade lol.
If you aren't going to take the time to correct me, or even try, don't comment
High SPL, Low Distortion, 2way... I didn't exactly achieve 2 channels....but, I can technically say its a 2 way sitting on top of a "sub" without being "wrong"
.The most important take away, I think, being that at least 3 channels are needed to create this experience properly....when we call "proper" Half space simulation. With the criteria that I would like in a mastering monitor, I had already set myself up for aiming for scientific SQ without saying it.
Sealed... I've always had a sort of fetish for powerful sealed bass, at the expense of never experiencing it and the clout of SQ. Now it seems there may be less differences than I thought between vent vs sealed when either are properly applied. There is also the idea that a PPSL is the shortest, offset horn....one could make
....basically a 50/50 hybrid lol sealed/vent. I'm ok with that too.Hybridization is welcome lol....I've got a tweeter mid, a vented sealed bass mid.....an enclosure wall lol.....Loudspeaker/headphone
People like TNT use dialog that wouldn't be used face to face...thats bad energy sorry. Regardless if thats his honest feelings, a pecking order and respect are real things also....that the internet allows one to evade lol.
If you aren't going to take the time to correct me, or even try, don't comment
More Criteria
All Sources Located on the front baffle....I pictured all sources, close together, all on the front baffle...
Best sounding in untreated room.... High directivity...High direct energy...done.
Close Proximity listening.... So yeah I'm sure this one gets the most laughs...for the obvious reasons (giant horn)....yet who has tried this for a year and how was his/her masters turning out lol. For mixing and mastering a person can learn an incorrect system and eventually reach consistent results... As an artist I am used to achieving the said, unachievable....happens all the time....what's achievable isn't set by another, and what happens in real life, matters more....at the end of the day, there are options so I won't loose sleep. I can easily....move my chair back, or adopt a waveguide......The idea was to analyze the beam width and come up with criteria and design towards it...I first was ok with polar width of the 350hz tractrix horn, and I said F'it and went big (150hz tractrix)...seemed to be the winning trend anyway. The more Directivity the...
All Sources Located on the front baffle....I pictured all sources, close together, all on the front baffle...
Best sounding in untreated room.... High directivity...High direct energy...done.
Close Proximity listening.... So yeah I'm sure this one gets the most laughs...for the obvious reasons (giant horn)....yet who has tried this for a year and how was his/her masters turning out lol. For mixing and mastering a person can learn an incorrect system and eventually reach consistent results... As an artist I am used to achieving the said, unachievable....happens all the time....what's achievable isn't set by another, and what happens in real life, matters more....at the end of the day, there are options so I won't loose sleep. I can easily....move my chair back
, or adopt a waveguide......The idea was to analyze the beam width and come up with criteria and design towards it...I first was ok with polar width of the 350hz tractrix horn, and I said F'it and went big (150hz tractrix)...seemed to be the winning trend anyway. The more Directivity the...Exactly. I am more concerned with the off axis transition being smooth, and the tractrix horn has no issues with that...at least a well designed one...and then benefits of the wide mouth and baffle, in that the larger frequencies that will interact, there, will not "see" the edges, due to frequency size. Tractrix Horn mouth and baffle width are matched....this will help bring about a good polar transition I hope to soon confirm with measurements...the simulated polars look promising to me...Off axis performance is obviously a criteria now but I had no knowledge of this topic before I came here. I also live in "the vice", already......So having a horn, that the hf polar width, is about the size of a basketball at -3db/17khz....was a "whatever" moment.... I immediately investigated my tolerance when I received horns to do so....things were as predicted....and I was not detoured in the least...actually now I have planned a horn twice the size lol....thats how much I cared about the beaming...but this is extremely personal and experimental, I'm not trying to sell anyone on this...this is just for me. Midrange is everything....I can easily create something else to mate the woofers and create another version of the system with a different tweeter approach....Honestly with that thought, I could switch back and forth between a horn and a waveguide depending on desired experience....with sound design, within music and the like, its the norm to wield multiple reference systems....if my multiple reference systems happens to require; unmount a horn and mount a waveguide.....so be it... just a concept, but its nothing unfathomable. I find the high pass filtering that sweeps down frequency as one goes off axis of the horn to be desirable to the process of eqing. Due to my other "out of the box" ideas, I have discovered how to use eq filters to expose resonate notes within the mix in a unique that I have not seen taught, though I'm sure someones doing it somewhere. Basically by sweeping a hp or lp you get rid of the majority of the spectrum on one side of the knee.....Sound from different tracks can "mask" other elements in the mix....also....sound surrounding the note under inspection...can cause a masking effect....ie...if you are inspecting the 400-300hz...sweeping a hp/lp filter through that area will make frequencies around the knee more perceivable. This trick works particularly well with high pass on the bass and midbass. So basically moving too far to one side of the horn or another is going to automatically move towards the same filtering technique that I use to expose resonate notes in the the material on the high end...as well have natural flat FR on axis...its a win win for ME....and highly personal lol....DONT COPY ME lol....Further more... lord knows all I have to do is move my listening chair back say 6-7ft.......this is still one hell of a system at that distance as well....waveguide or horn....all we do is win.
Intelligent quote....This design I have, as is, is a very simple design, with complimenting dimensions and bandwidth capability for proper crossing over...
I mean its just a horn on top of a 15" on top of 18's....as said, the PPSL, is the only "complex" thing I've got going on here...and its issues seem to be easily low passed.... With decent room placement and DSP I predict good things.
Took me a second but I finally figured out why you said this....you are jealous...oh well. Monkeys don't work....or have money....and no one I know is handing expensive paints and canvases to monkeys....If you work hard and save your monies, you too! can afford expensive canvas and fine oil paints....and if someone tells you that the painting you made was bad, you too, can tell them, to go, themselves.
Did you say recently that you were looking at a vertical pair of 15” woofers with your horn on top @camplo? You’re also going to be using DSP with the system, right?
If so, you can perhaps help your goal of directivity by learning about the application of all-pass filters:
http://www.excelsior-audio.com/Publ...s_Filters_to_Improve_Directivity_Response.pdf
You can experiment with these in VituixCAD.
If so, you can perhaps help your goal of directivity by learning about the application of all-pass filters:
http://www.excelsior-audio.com/Publ...s_Filters_to_Improve_Directivity_Response.pdf
You can experiment with these in VituixCAD.
Thank you for your help @kyleneuron. For a long time I wondered what allpass filters were, I finally stuck one into the pipeline and viewed the effects. I think that my experience eqing music has given me an advantage at filter design? I was able to use the the allpass to create better looking crossings in situations that otherwise, did not look so nice in predicted polar. I've used VituixCad like I've used Hornresp, as a sort of gym? Sim a bunch of stuff over and over and over and over....trends start to show.
Its so funny one of the people here that consult me, just commented that a PPSL might cause "interference" and that a TMM with side mounted subs would be more logical? I finally put some nails on some hammers and have the subs boxes constructed, enough, to run some measurements. Of course things did not look like the sim...I never took the time to learn Akabak, but the HornResp sim was very helpful. Having opposing woofers, I thought that some type of cancellations would occur but not sure how to predict them. I took some crude measurements I want to share, but they are up stairs on the laptop. There is an..."oscillation" in the FR but not strong, like less than +/-2.5db....The resonate note is not where I thought it would be...sorta confusing....its about 100hz higher...250hz instead of 150hz...The response is pretty smooth considering the resonant configuration. Its usually at this point I'll ask if anyone has some detailed measurements of subs that would be a good compare and reference for high performance or text book performance. GD looks crazzzyy lol! I am sure that brings a smile to sooo many peoples faces!
". ERB smoothing uses a variable smoothing bandwidth that corresponds to the ear's Equivalent Rectangular Bandwidth, which is (107.77f + 24.673) Hz, where f is in kHz. At low frequencies this gives heavy smoothing, about 1 octave at 50Hz, 1/2 octave at 100 Hz, 1/3 octave at 200 Hz then levelling out to approximately 1/6 octave above 1 kHz."
ERB smoothing is one the few options that draws a trend line almost (not quite) identical to the simulation. So here, expressed in the GD, are the cancellations that I predicted but did not know what its manifestation would like....the oscillations in the FR are likely a result as well....I feel like the low frequency number helps to sorta slip through the cracks on issues the slot causes.....
I stressed getting the output on the front baffle with this logic....I am creating a "picture" that is being broadcasted in separation, via tweeter, mid, bass etc.....it seems logical that the closer I can get all sources, the easier, of a time, they would have, recombining. Hence the PPSL. Its the smallest footprint I could create that allowed the channel to reach desired output vs excursion. Then again, I also designed towards my spl goals using just one channel. The shape of it creates an "Aperiodic Bi-Chamber" lol did not do that on purpose but I have a habit of getting things right on accident, add vibration cancellation to that list as well. I theorized that the opposing backwaves would help cancellation inside the box...
I had to take one sub apart and re insert the threaded rod....only took 8 hours....
I spent the better part of a day, listening to vocals through the Axi, its already apparent that the long study and help received here at DIYA, is paying off. Amplitude distortion is low....the bad audio work on some of the shows I was watching...unless they intend for the crowd to be so much louder than the performance. Lord have mercy, dynamics are not inhibited with a compression driver + horn, let me tell you lol.
I found that one of my favorite bands has material I haven't heard! Something good that actually came out of Sweden. I've heard some good jazz come from there also...It seems that the Swedish have taken a liking to Black culture.
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Remember to distinguish between curved and straight cones, as the shape can have a significant impact on the radiation pattern.
This is indeed the most effective way to deal with low frequencies, but places enormous demands on the foundation. Otherwise there is a good chance that the bass wall will sink into the earth.
Legis' solution is far more practical and works well into the mid-range.
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