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Multi-Way Conventional loudspeakers with crossovers

Is it possible to cover the whole spectrum, high spl, low distortion with a 2-way?
Is it possible to cover the whole spectrum, high spl, low distortion with a 2-way?
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Old 23rd May 2020, 06:04 PM   #5991
diyiggy is offline diyiggy
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Hello camplo,

after 599 pages, what are your today conclusions about the choice for your small distance monitor please ?

2" Compression wave guide with a 15" or 18" non horned ? 100 to 115 db efficienty drivers ?

smaller tweeter with wave guide and very low distorsion 8" ŕ la Purifi...87 dB drivers, several needed to increase spl efficienty and max level with less HD ?

I mean yo listen in near field and use active powerfull pro amps & eq. What your max spl peaks needed in your roadmap of the perfect monitor ? And your average listening volume (if ever the question has sense in a reccording & professinal context) ?

Last edited by diyiggy; 23rd May 2020 at 06:06 PM.
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Old 23rd May 2020, 07:16 PM   #5992
mitchba is online now mitchba  Canada
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Originally Posted by camplo View Post
Yes and yes. lol I didn't even do anything! You guys started Arguing about horns, I'm just an innocent bystander lol! The majority of people arguing horn ethics here, have way more experience than me, I can't say that either side is winning...


Jacek Zagaja seems to have a wealth of real world experience with a lot of these horns....hes not team constant directivity or beaming....rather talks about which does what well...according to him, beaming horns are perceived as the most neutral...Ro808 noted that these traditional horns have the most neutral playback, that in no way lines up with the idea that constant directivity has an edge in neutral presentation...Why haven't they taken note to this supposed coloration expectations invited by reflections?
LOL! OK I thought I had missed something :-)

Regardless of sides, here is a little listening test to try once you have things set up. Play a song that has 8th or 16th notes hi hat sound. We want a repetitious hi frequency musical sound (10 kHz). While listening, move your head slightly off axis. Does the hi hat "tone" change? Does the hi hat "level" stay the same or drop off or become hotter when you move your head. Try moving your head in an increasing circular pattern around the centre point at your listening position and listen again for hi hat tonal and/or level changes.

Regardless of models or measurements, from this little listening test, you can draw your own conclusions about HF directivity and its relative importance... to you.

Good luck with your build camplo!
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Old 23rd May 2020, 08:22 PM   #5993
xrk971 is online now xrk971  United States
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Is it possible to cover the whole spectrum, high spl, low distortion with a 2-way?
Hi Campio,
You quoted me but not sure where you got this as I did not say this:

Quote:
I'll be starting my own thread very very soon, and will not be posting here as my choice of reviving a quote from February 1st was a complete derailment of the thread in its current state...maybe even initially so
I did start a thread on the PTT6.5. Just thought I would point out that it really is a transformational driver that answers the question you posed on Post #1.
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Old 23rd May 2020, 10:29 PM   #5994
camplo is online now camplo
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Quote:
Originally Posted by xrk971 View Post
Hi Campio,
You quoted me but not sure where you got this as I did not say this:



I did start a thread on the PTT6.5. Just thought I would point out that it really is a transformational driver that answers the question you posed on Post #1.
I'm a mind reader...

You should give a link to your thread...
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Old 23rd May 2020, 10:38 PM   #5995
Richard Ellis is offline Richard Ellis  Argentina
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For awhile no, I'd been modeling up a similar two-way according to your parameters...I had settled on a 375 liter enclosure, tuned to 33.5 hertz, ported at 200mm by 150mm, at 82mm deep.
The Audio Nirvana "Classic" 15 for the bottom, an Aurum Cantus G3 for the top end.
Although the big 15 has some 5-10 Db on the big Aurum ribbon, I was thinking of running the AN full-range & the ribbon cut-off at 2500, the summation of the two SPL curves just might work...& the phase I'm guessing would "like" just being off 90 degrees just for the ribbon.




------------------------------------------------------------------------Rick......
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Old 23rd May 2020, 11:50 PM   #5996
xrk971 is online now xrk971  United States
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Is it possible to cover the whole spectrum, high spl, low distortion with a 2-way?
Quote:
Originally Posted by camplo View Post
I'm a mind reader...

You should give a link to your thread...
Simple Passive Harsch XO Using PTT6.5 and RS28F in a Waveguide
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Old Yesterday, 01:11 AM   #5997
camplo is online now camplo
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Quote:
Originally Posted by diyiggy View Post
Hello camplo,

after 599 pages, what are your today conclusions about the choice for your small distance monitor please ?

2" Compression wave guide with a 15" or 18" non horned ? 100 to 115 db efficienty drivers ?

Smaller tweeter with wave guide and very low distorsion 8" ŕ la Purifi...87 dB drivers, several needed to increase spl efficienty and max level with less HD ?

I mean yo listen in near field and use active powerfull pro amps & eq. What your max spl peaks needed in your roadmap of the perfect monitor ? And your average listening volume (if ever the question has sense in a reccording & professinal context) ?
Well the dynamic driver side, I nailed it, as far as I'm concerned.... The Acoustic Elegance drivers have never been contested by the forum, outside of people being skeptical that a subwoofer could have specs like the 18h+... rather that there were potentially equally good drivers at a lower price, maybe...my experience with modelling suggest to me that whoever designed these woofers spent a lot of time making sure that at least the 18h+ and 15m mate very well...I may have just gotten lucky, but they compliment each other a little too well, for it to be a coincidence...the strange FR of these woofers, when combined easily turn into a flat FR...how one does this on accident or by chance, is a long shot. It could be a result of similar design philosophy. The rising sensitivity of the large woofers turns into a good thing in application

The slot loading of the dual 18H+ woofer section is a place I could not have foreseen ever landing...inspired by the intentions of keeping the output as close as possible to the ear, my forever long attempt to increase direct energy over room energy. I understand a little of how this could be turned into a ripole...I bet there is some advantage still, without being a ripole, related to the increase in velocity out of the slot.

18h+ is 98.7db MMS 165 g, QTS0.22, LE 0.41mH
15m is 97.8db MMS 70g, QT S0.33, LE 0.2mH

I do have a variant on the 15m. I was fortunate to be able to purchase 16 ohm voice coils.

If I could do it all over again what would I differently...hmmm. Not much of anything I guess...The woofer section is already versatile enough that I can adapt it to any other HF solution. I mean the 15m and the 18h+ are all star woofers, how can you go wrong with that?

Purifi woofers... everyone seems to be jumping on this train..."“Real” long-stroke
performance: distortion remains low over full excursion"....These woofers can't defeat physics, only harmonic distortion is lowered, thats the one detail they left out...inter-modulation distortion is a function of excursion length so you'd have to use multiple Purifi woofers to fairly compare. Now that you've increased surface area with the multiple Purifi woofers, harmonic distortion isn't a factor anymore because they aren't stressing excursion limitations anyway...

The excursion of the 18h+ and 15m at 100db @ 1 meter is ridiculously low.

Dual 18h+...100db... 30hz... 1.7mm displacement...
15m..100db ...47hz LR12db high pass... 0.7mm displacement

Thats just one side, in halfspace. Harmonic distortion? Where?

Once I get it into a real room, there will be potentially more bass boost, but also room correction needed, the headroom is there for the room correction as needed. I'm pretty sure my particular room is screwed, there will be a dip somewhere around 100hz I bet. This living space is temporary but I imagine that the next step involves proper room acoustics. I already believe in using multiple subs, so expect 2 more subs. Sometimes I wonder if I should just remove the slotted design and just run 4 subs since I have 4 woofers already. Then I'd loose the force cancellations and the directivity caused by the slot, as well, the uniqueness, not to mention a large amount of dampening. The impedance peak is at 19ohms. The 15m is impedance peak is 42ohms...40's and lower seems to be a trend for a lot of these highly regarded designs...40ohms for a 15" driver is really good I think. 19ohms for 18"'s... thats excellent.


As for the HF section...there are so many possibilities, if by chance I decided that the Axi just isn't the answer. For example; add a 4" woofer and a 1" tweeter now we have a 4 way....

I have an idea that a horn and a large diameter woofer have a lot in common in the terms of efficiency. I've spoke of my theory that a larger source has effectively a longer projection of direct energy. I haven't made it to that level where I am discerning amps....but those amps are used and relatively cheap and the DSP in these amps are cost several thousand dollars new, let alone the price for the amp brand new. If anyone comes across some used PIP-USP4's....I'll have FIR filtering, not that I'm looking.

So why aim for such high dynamic potential....The people who design the signal (sound engineers) have discovered that the closer you reach excursion limitations, the drivers compress the signal more....compression at the engineering stage, that isn't intentional, is baaaaadddd. The most important tool in the sound engineers arsenal is the EQ, how can he judge frequency dependent SPL if the speakers are coloring the signal via mechanical compression...unfortunately I never figured out how much headroom is enough...so I've never heard of negatives derived from having too much headroom, and with the interest of maximizing this aspect, I reached for the stars, in so many words, in order to at least land on the moon if I under estimated the challenge. I can only imagine that spl is always expressed cleaner and more accurately, directly in relation with the lowering of excursion. One suggested monitoring level for mastering is around 75-78db... I also am hopefully that thermal compression has been erased in this design. The heavy lifting (low bass) has been split already 4 ways...

Another thing to note, is that this system can be used in the far field and still have pretty good results, distortion wise. Versatility is good right?


So if I were reach into my pocket of out of the box....How about ripole woofers at a very close proximity?? Think you still need like many large woofers per side to get the levels I was reaching for at 30hz though.

How about building a system that can play the range you need, with proper technique and aspects, with small drivers, and have them mounted on a fancy bracing system to hold them near your head like 12inches away... Small woofers have lower resonance than larger woofers. If I were to mimic my system, you'd want to be able to hit atleast 115db by xmax, 30hz @ 12 inches listening distance. Hail Direct energy, and down with room energy. This is not the same thing as using headphones (I just know someone will comment this) headphones create a tiny room between your ears and the driver and unfortunately having the drivers encapsulated onto your ears, changes the relationship of how bass transfers, so that you cannot eq bass well. Maybe a small system mounted 12" could fix that while maintaining the precision of headphones?

Last edited by camplo; Yesterday at 01:14 AM.
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Old Yesterday, 01:19 AM   #5998
camplo is online now camplo
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Quote:
Originally Posted by DonVK View Post
It's a long thread. Maybe you could list the horns that meet your aspirations. I'm sure you've had many suggestions

Many of the @docali horns I have simulated have the best formed wavefronts (exiting the horn) that I have seen. Yes, they will narrow with frequency (as do cones/domes), and they might not fit everyone's preferences. I still would like to fabricate some smaller ones (still working on this part) and actually listen to them.

.
Well I feel like the HvDiff we did is a masterpiece...I mean look at the polar....and for a horn that loads so low...just wow. Docali has been at the grind stone, just recently he pops out of the blue with these new bi-radial designs, and I start to perspire...but I'm also getting the picture that you guys have a passion for this stuff so a lot of it is a labor of love, as we all spend hours responding and helping others, it brings light to our own ideas and challenges, so I get it!

Docali's 300hz Radial Jmlc has me like but he's not finished with it. It will be up to Docali if he wants to show off those polars.'

Quote:
Maybe you could list the horns that meet your aspirations.
OK here's a quote from a trusted source
Quote:
Horns require minimal crossover - just HP, SPL is flat on axis that's why popular.
Small horn like jmlc-1000 can be perceived by people like waveguide.
Large like jmlc-350 beams like estat. Larger can't be used full range. Multihorns require larger distance to integrate.
Waveguides require careful eq possibly dsp.

CD is nice if you want wide sweet spot/ stable stereo and that's all.
Sound on your face for both horn and CD waveguide - less reflections means sound goes forward. If you want spacious sound you need proper recording or omni radiation and prepared room.

I use esl57 that beams a lot and I'm happy even if not hear highs off axis. Tonal quality/accuracy is my strongest desire.

Geddes Summa copy (15" wg and baffle radii) is I think good starting point to evaluate things. I would try make it 3 way with mids also in wg and woofer with Cms near 0,5mm like Eminence Legend BP
First of all, The HvDiff, as a 350hz horn, will probably knock it out of the park. Docali (and I) like the recent bi-radial designs ... I like it, the more you guys blend the circles with the squares... Which is why I like the jmlc bi-radial he designed
The AXi2050 is wide range enough that the comment about the 350hz jmlc could apply.
The Horns that are more wide than tall tip things to our favor, without a toll on the on axis FR....
Can we go over the formula to predict beam-width again?...
Lets just assume the Axi2050 is going to be successful up top till 19khz-20khz, which isn't disputed by the measurements provided by Keith1962. From the get go, I had accepted that compression drivers and 10khz might be at a loss....the Axi2050 changed my impression, but non the less, I accept the first impression, to impart itself, somewhat. If we set a goal criteria for beam-width in the high band @ 1 meter, lowering loading depth in priority and see where that gets us... that makes sense to me.

5460(1.5KA/19.05)
= 429.92

5460(1KA/19.05)
= 286.61417322834645669291

5460(2KA/19.05)
= 573.22834645669291338583

I'm slightly worried to approach KA=2 for nearfield. Maybe someone can confirm or deny those feelings.
I only have 2 theories for crossover destination, The first is the one I've pushed all along; pushing it low enough to not break up vocals, and second, right below beginning of the critical range (700hz) so at about 630hz or so....which also just so happens to be the xover point for the JBL and some type of mathematical middle for the hearing spectrum....but the KA is too high for my woofer up there. I need more theory to support a certain xover between the bottom of the vocal range and beginning of the critical range....300HZ sounds about right to me, tbh...I just opened my daw, and a random project, with acoustic bass and piano, experimenting with a low and high pass filtering....300hz sounds like a great spot for a xover...just so happens thats where the Axi2050 is designed to cross....

300hz xover? Why not....the interesting part to me is the idea of having the a horn that properly crosses at 300hz (150hz fc) vs one that works anyway, which potentially may be a horn with a 300hz fc. Somewhere, as we move up the register, the detrimental effects of the tuning note, are at a loss....otherwise waveguides wouldn't be acceptable, being that the exaggerated decay and group delay become a non issue....where does the transition occurs?

The 18H+'s in the slot potentially have a resonance around 300hz so my desired shallow xover performance in VituixCAD is showing that I should, in order to keep the hump out of the immediate on and off axis, crossover 350hz and above and I like what I see 440hz and under . I experimented with high and low pass filters on a track with piano and acoustic bass....300hz sounds like a good position, 350hz is right there with it, and supports the direction things have been going. Yes I could cross the 18h+ over differently but I like the large overlap of frequency coverage, down there. So far I don't see the need for anything but minimum phase xovers.

I've been building this and the last post so long that I cannot be sure I even answer you question Don...and its dinner time...I will revisit this and see if it inspires me to say anything else, maybe in a more concrete manner.
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Old Yesterday, 06:03 PM   #5999
camplo is online now camplo
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Quote:
Originally Posted by mitchba View Post
LOL! OK I thought I had missed something :-)

Regardless of sides, here is a little listening test to try once you have things set up. Play a song that has 8th or 16th notes hi hat sound. We want a repetitious hi frequency musical sound (10 kHz). While listening, move your head slightly off axis. Does the hi hat "tone" change? Does the hi hat "level" stay the same or drop off or become hotter when you move your head. Try moving your head in an increasing circular pattern around the centre point at your listening position and listen again for hi hat tonal and/or level changes.

Regardless of models or measurements, from this little listening test, you can draw your own conclusions about HF directivity and its relative importance... to you.

Good luck with your build camplo!
Thank you so much Mitchba! You past shared experiences, through the DIY community, has a direct connection to this build, I was stalking your posts, well before I purchased a woofer. Though the design has taken its on unique path, that path starts in inspiration of your love for your system built around the 4722.

The test you suggest makes perfect sense, I did a similar test with the Altec clones I audition'd early on using a special reference track, though what suggest, will be more revealing. This track here, is golden for judging imaging...if you are able to hear it in excellence you'll see what I mean. The imaging on those Altec clones in that room...mind blowing.
YouTube

Some thoughts, when auditioning the Altecs, its been so long since, but I do believe that I tried setting up a 1m or 1.5m situation...and with those, what I now am sure were the 511 horns, I was fine with the so described head in a vice. I do everything ITB so its not like I have to move about a console.

So I guess we'll see.

Quote:
Originally Posted by ErnieM View Post
Lots of good info! The low frequency performance is impressive..looks like it'll make smaller synergy horns obsolete by eliminating the need for close spacing at the throat.

I think 300hz is probably safe when combined with direct radiators but it might be wise to raise the crossover a bit if combined with a high power mid-bass horn section. They mention that the area is approximately the same as a 5.5" dome. It has 1mm of linear travel. It can only move so much air. For a very loud and clean horn-loaded point source PA system I would use it above 450hz.
- New Celestion "AxiPeriodic Driver"

Just when I was about to cry about not being able to see thiele specs of compression drivers. Where is it mentioned that the Axi2050 has 1mm of linear travel?
Lets pretend for a second we can trust those specs...how do I formulate how low it could play at 300hz within 1mm, no horn?

Last edited by camplo; Yesterday at 06:16 PM.
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Old Yesterday, 06:39 PM   #6000
camplo is online now camplo
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Guess I should have kept reading

Quote:
Originally Posted by Patrick Bateman View Post
Some random thoughts from sitting through the whole hour of the Celestion video:

1) Celestion's justification for the axiperiodic design is that the BMS coaxial design has HOMs. But there are two ways to solve the HOM issue in the BMS design:
a) put both diaphragms equidistant from the throat, which is exactly what JBL is doing in their D2 drivers
b) I have a hunch that HOMs are lessened with wider waveguide angles. I've definitely noticed much worse HOMs on very narrow angle horns. (Car audio horns have angles as narrow as ten degrees.)

2) The manufacturing of the CD sounds painfully difficult.

3) People keep comparing this to a Unity horn. Keep in mind that a Unity horn will still have dramatically more output below about 700Hz because the AXI 2050 is displacement limited. In the video they mention that the AXI 2050 phase plug is less than one millimeter from the diaphragm. A Unity horn has something like 4X the displacement of an AXI 2050 in the range of 350Hz to 1400Hz.

This isn't to dismiss the design; it makes a lot of sense for Celestion because it's a simple solution to a common problem; a Unity horn will produce more output for less money, but it's also hideously complex.
Quote:
Originally Posted by ErnieM View Post
So the 1mm figure is peak to peak. Half of what I was thinking. Still a very welcome improvement in wideband compression driver tech. Consistent and efficient manufacturing will decide whether it lasts on the market. (A bit obvious I know)

FIR is making some of the problems solved by this driver into trivial issues in the sound reinforcement world. Combining the two would be very nice of course. All depends on the price compared to BMS.




I think I found the source of the info YouTube

Last edited by camplo; Yesterday at 06:44 PM.
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