Well I avoided TMM from day one because I was in belief that the view angle vs ka was not to my liking. As I stated above, I was overly critical of Ka, it seems that a ka 2 is of my liking so the higher view angles and xo's I might not of entertained for a TMM before.
"Why are you taking ka=2 as your upper cutoff? Do you want an omnidirectional response? If so, why the interest in a horn?" I'm not, its actually lower. The tweeter is the limitation on my horizontal viewing angle. I need the midwoofer to have a similar or wider polar pattern at xo.
"I would never use more than +6db of EQ." - I am not aware of any limitations on boost or cutting quality per db but I haven't had to always use eq filters that high or low....rather...I have had to turn up the gain 20db or more
"Why are you taking ka=2 as your upper cutoff? Do you want an omnidirectional response? If so, why the interest in a horn?" I'm not, its actually lower. The tweeter is the limitation on my horizontal viewing angle. I need the midwoofer to have a similar or wider polar pattern at xo.
"I would never use more than +6db of EQ." - I am not aware of any limitations on boost or cutting quality per db but I haven't had to always use eq filters that high or low....rather...I have had to turn up the gain 20db or more
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Hello Camplo
You are talking about speaker response from the enclosure as designed. Ideally you shouldn't have to do anything, it should be good without any EQ. Now obviously once you put it in a room things will change but the native response should be good to go with very minimal EQ if any at all. In a room you will be using notches to reduce peaks not adding significant + EQ
So let me get this straight you spent all the last couple of pages worried about linearity issues due to driver excursion. What do you think is going to happen when you dump in +10 db of EQ at low frequencies below 80Hz?
You also by default lost 10db of headroom and are dumping all of it into the driver so you are just getting it nice and warm to bring on power compression long before it should even be an issue.
10db 10X power 20DB 100x power not sure why you would be adding 20db of gain for EQ?????
Rob
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Earl,
I would not equate the use of either a large diaphragm (4” equivalent) HF driver compared to a small diaphragm (2”) driver as a good or bad choice regardless of their power handling.
The use of the larger displacement HF driver allows a lower crossover point, which would be useful in a 2-way with large demands on the woofer down at 30Hz, common in many contemporary music genres.
Considering that Camplo is designing for three-way, not two-way, the use of a 4” equivalent driver for the HF is really not necessary, though that does not make it a bad choice.
That said, using horn/drivers without uniform dispersion for studio monitoring is definitely not a good choice.
Roy Delgado’s use of an additional “extended wide dispersion phase plug” on the AXi2050 driving the 1meter wide constant directivity K402 horn in the 2021 75th anniversary Klipsch Jubilee two-way crossed over at 300Hz is interesting.
But as Roy said “it’s gotta be DSP” ;^).
Art
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Who said its a 3 way, According to your description, using a large 4" compression driver with a woofer is bad idea if also using a subwoofer. Wrong. Placing a XO lower in midrange is proven as a benefit to SQ in midrange. Each configuration comes with its own pros and cons. Placing a XO higher has cons, and you know it, its been known. its funny the Xo in the Strauss is 400hz....go tell that guy his XO is too low. I don't know if thats a good rebuttal but I said it lol.
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The response here looks odd, if you want some help with it then post the VituixCAD project, it is very hard to know what is going on from a screenshot. How did you make the measurements for these drivers?
The Gain block is normally used to allow differences in sensitivity to be accounted for, but can be used to rebalance the response of drivers from other EQ in an active system.
Filter gain is something else and there when you boost a specific frequency you will most likely need to make a corresponding gain cut to avoid clipping.
There is no limit to the boost you can use but the more you use the more the overall gain will have to be turned down, limiting overall SPL potential.
SL's dipoles used 20dB of gain for the woofers and I use a fair bit in my line array. Neither is wrong if you understand what and why you are doing it.
This is correct, if you take a minimum phase response and equalize it to flat with minimum phase filters the phase will be fixed along with the frequency and there will be no group delay.
But it is quite possible to have a flat frequency response and non flat phase response from crossovers filters etc.
ok thanks for the reassurance. I know what Rohb is worried about. I am speaking of using the gain block to rebalance. My headroom is limited to power and excursion. Which I have too much of on purpose. Bending the lf roll off into shape using filters has always been the plan and is common for a sealed enclosure aiming for a lower F3 using a low Q driver. Getting the Hf roll off, out of the picture, as a result pushed the rest of the response so low I have to use unity gain to get it back into normal sensitivity range. Still there are limitations. I need 40db of gain to get to max spl goals. I've got 24db of unity gain at the eq and 20db at the input and 40db at the output. Seems that I should ok, as long as cut/boost in the right places to end up with cleanest signal in the end regarding noise floor.
Heres my VituixCad *File*
I am flattered that you would take the time to help. I am not against reconfiguring the woofers but truth be told with this configuration pulled off excursion is very low on the middle woofer.
WelterSys - you call this a 3 way....well then any other 2 way utilizing a lower woofer as a sub is also a 3 way in your rankings. To which I can't 100 percent disagree...but I feel defensive to calling this a 3 way because show me another 3 way with a 100hz XO to a lower woofer....Calling it a 2 way with subs (2.2way) or a 3 way would not technically be wrong ( making a 4 way plus sub a 5 way etc etc).... The approach has been basically to design a capable horn loaded 2 way....and then another set of woofers on the bottom to improve where possible. Being able to crank the volume and know that excursion will never rise significantly on the mid woofer is what the lower woofers have allowed. The roll off of the system without the lower woofers is still within the range of normal use I think...with that being true(I should verify) that makes this system somewhat unique if you must stamp it with a 3 way badge....show me another system where the lower woofer is...."optional"....I'll show you a 2 way with "subs".....I've been known to make up words...we can call it a mid assisting sub if you'd like but the highest xo point standard I've seen for subs is the THX 120xo .....crossing at effectively 100hz or so...is still sub territory so once again....calling it a 3 way......is it really though?
The flat to 30hz goal requires at least 2 18"s to make this happen sealed comfortably within 14mm xmax at 115db. Based on Pink noise, at 80db, 30db for transients, 80+30 is 110 so.... close enough to 115db at low end....down 6db by 600hz or so (99db) and down another 6 by treble end (93db)...... having even more headroom than that allows accurate monitoring at louder volumes above 80db within those areas headroom allows but is not required? I can't say? considering many systems aren't within xmax at 115db voiced neutral to 30hz any way since its such a large task for the basement guy.
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That is a lot of gain and I'm not sure why it would be needed. You need to zip up all the measurement files, just saving the vxp file doesn't add all the measurements in.
Maybe it will make more sense when I can see what you did.
Mock up of TMMW...A lot of things to like....Still reaching 115db at 30hz within Xmax... 2mm@30hz on Dual 15's working with 18" pushing 14mm to reach that. If I use filter to curb more excursion on the 15's the 18 still has enough help from the 15's to support 115 system total at 30hz 1m within 14mm xmax of 18h. This option frees up a pair of 18"s to use for 2 more subs to basically complete the system.
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Like Carrol Shelby said: "There's no replacement for displacement" and "too much power is just enough".
That said, having way more SPL than you need is an invitation for inevitable hearing damage.
There are literally thousands of examples of commercial 3-way systems with the LF crossover anywhere between 50 and 1000 Hz, many using 18".
The early 1980s JBL 4435 was a 2.5 way studio monitor using two 15" and a 1" exit HF crossed over at 1000 Hz, the second low frequency driver used for assistance below 100 Hz. It was rated for maximum continuous output of around 120dB down to 30Hz in JBL's test room. The single 15" 4430 was rated close to 115dB at 30 Hz.
Your system will be what it is whatever you want to call it, though normally a system which has speakers co-located, whether they are in the same box or not, is designated by crossover points, the frequency of the crossovers are just a technical detail.
Previously you were planning to run your 18" as high as 200 Hz, you now seem to have dropped to a reasonable 100 Hz or so, so their off axis response won't be bothersome.
You could cross your 18s" at 40 Hz, and still cross your 15" at 100 Hz, the "underlap" would compensate for the rising response of sealed 18s", and require less PEQ if your DSP does not allow enough.
Art
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This is the best, simple, crossing, I did with the slot loaded woofers. That dip at 200hz....that even a big deal or no? I don't like how FR is a result of cancellations at that particular part of the spectrum but like I said, the slot it more trouble than a minimum phase, low order, xo would like to deal with....
Is it perceivable or something I should care about looking at it in the graph?
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I can almost imagine what it sounds like...I'm looking for a reaction I guess...like "ooo thats good" or "I wouldn't accept that".....I guess if it was unacceptable someone would warn me right? That area where I actually lose sensitivity/efficiency at 200hz....maybe that was some kind of design red flag. Me not know.
Heres what I can get done with a 1st order AllPass
Believe it or not I've modelled TMMW before, last time I had a mid design crisis, and the TM-slot loaded WW is more efficient than the TMMW. The in room response predicted via VituixCad suggest that the TMMW is more room friendly which I attribute the redundant sources of bass on the vertical plane. The draw back that I see for the TMMW is a slight loss on imaging due to redundant midranges. The TMW is the more eloquent solution. The TMMW has more.....midrange prowess? It is more room friendly and the room is very important.
I bought 4 more 15"....these will either become midbasses or the supporting independent multi basses
So either slot loaded pairs of 18"s up front with pairs of sealed 15's in the back or...
Sealed 18"s up front with sealed 18's in the back.....15's used as midbasses for mains.
Heres my thought.
pros- The TMW will image better due to lesser sources. The PPSL 18" bottoms will be impressively dynamic.
cons- potential issues regarding resonances in the slot affecting phase and decay
Pros- The TMMW will have higher clarity in the mids. Summing and Phase is initially much better with this config as well as better room response
cons- Dual mids = Dual woofers imaging not as good as single. Slightly taller enclosure needed.
Opinions?
Heres what I can get done with a 1st order AllPass
Believe it or not I've modelled TMMW before, last time I had a mid design crisis, and the TM-slot loaded WW is more efficient than the TMMW. The in room response predicted via VituixCad suggest that the TMMW is more room friendly which I attribute the redundant sources of bass on the vertical plane. The draw back that I see for the TMMW is a slight loss on imaging due to redundant midranges. The TMW is the more eloquent solution. The TMMW has more.....midrange prowess? It is more room friendly and the room is very important.
I bought 4 more 15"....these will either become midbasses or the supporting independent multi basses
So either slot loaded pairs of 18"s up front with pairs of sealed 15's in the back or...
Sealed 18"s up front with sealed 18's in the back.....15's used as midbasses for mains.
Heres my thought.
pros- The TMW will image better due to lesser sources. The PPSL 18" bottoms will be impressively dynamic.
cons- potential issues regarding resonances in the slot affecting phase and decay
Pros- The TMMW will have higher clarity in the mids. Summing and Phase is initially much better with this config as well as better room response
cons- Dual mids = Dual woofers imaging not as good as single. Slightly taller enclosure needed.
Opinions?
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Your modelled woofer looks better in the graph and your horn needs some EQ
Without seeing what you did with the whole project anymore is just a wild guess.
Im just focused more so on the woofer section atm.
just thinking....regardless of the audio aspect. The TMW is simpler to configure regarding phase. Ideally I'd want to configure each woofer separately the TMMW requires another amp/dsp. Also, the TMMW is actually comparable in efficiency. TMW has more bass prowess the TMMW has more midrange prowess. In either case, 2 more independent subs will be created
just thinking....regardless of the audio aspect. The TMW is simpler to configure regarding phase. Ideally I'd want to configure each woofer separately the TMMW requires another amp/dsp. Also, the TMMW is actually comparable in efficiency. TMW has more bass prowess the TMMW has more midrange prowess. In either case, 2 more independent subs will be created
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It's difficult to tell what is going on, half your directivity graph is missing the rest odd, which suggests the measurements or simulated data has some issues.
The top graph has good DI but the room positioning has a massive dip near 100Hz which is not good.
The bottom one avoids this but has 0 directivity which does not seem possible from such large drivers on that size baffle.
The top graph has good DI but the room positioning has a massive dip near 100Hz which is not good.
The bottom one avoids this but has 0 directivity which does not seem possible from such large drivers on that size baffle.
Not sure what you mean as vertical stacking won't affect the horizontal response.
Considering the placement constraints and overall system response will get to a better result so your ceiling will be a big factor in what works best.