That's a good point. I've never really bothered to take care of ceiling reflections in that way. For $5000, it would be cool to have a little servo motor that varies the height of the tweeter above the woofer.
That would be a little like having a triode/pentode switch 😀
The ceiling can be a problem. You want to make sure it doesn't come back in above the cross. Absorption up there can give good results and relax the compromises in the speaker.
The ceiling can be a problem. You want to make sure it doesn't come back in above the cross. Absorption up there can give good results and relax the compromises in the speaker.
I have a problem with that approach.
Totally understand what's happening here - getting more distance between tweeter and midrange shifts the null to narrower angles and get's the level back where we ESTIMATE the ceiling and floor. BUT - this only works for an estimated listening area in an estimated room.
When you e.g. stand up and want to listen to your speakers - you will have a pretty strong null, it will sound different as sitting. I also often have a near field listening situation - a close distance of tweeter and mid comes closer to the single point reproduction I am used from coaxes (LS50). That's the reason I don't do D'Apollito nowerdays - it has some vertical "spread" in my listening comparisons compared to a point source. (This is probably not audible in 3m distance in a reverberant room - but it's there and audible in my studio room)
Professional speaker like KH120ii sound very good when you move through the room - very close to a coax (compared 1:1 with LS50. Significant difference is only at pretty close distances). They try to get the tweeter close to the woofer and NOT produce lobing at ceiling angles.
https://www.neumann.com/globalassets/digizuite/37720-de-vertical-directivity-plot.png
Maybe it's my PA background and the sensitivity how a speaker sound across the room - but in my experience a close tweeter/midrange sound more like a point source and more even across the room. And that's my goal - even if the simulation wants different ;-)
We are talking flawless. As there are manufacturers which are able to do it - it's the standard we should aim for.
I know some Seas Coax speakers - while they sound good in the room you hear these interferences in a nearfield situation. Not flawless.
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It reminds me of my comparison of an Adam monitor speaker to KH120 monitor speaker in 3 different rooms. Adam is built similar to a HiFi Speaker, KH120 with waveguide.
Adam has more bass (bigger LF driver for the same money) and sparkling highs. But sounded different in every room.
KH120 alwasys sounded like the KH120 - just in a different room. Having controlled directivity keeps your room response more natural, independend of your position and the room.
The Adam was nice to listen too, KH120 is a reliable tool.
Many people are used to big room reflections. In my listening room you have nearly no reflections and sometimes people are asking "where is the wide stage". This means people are used to these reflections and the "artificial" widening of your sound stage - and like that! So waveguides are not for everyone and every situation.
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Then add some 25mm additional wood with 25mm roundings at the outside to stiffen the (horrible) cabinet. Make them closed and stuff it. Develop a proper crossover. Easy doable for 1000,- all together.
But you would need a subwoofer in addition to get fullrange - so at least 500,- more.
Would be a great base for home cinema and music systems, really affordable.
But you would need a subwoofer in addition to get fullrange - so at least 500,- more.
Would be a great base for home cinema and music systems, really affordable.
@IamJF Nearfield listening is a special case, so I don't consider that a relevant context. Regarding the "right" vertical reflection angles, the ideal would be to design around your room. But the CTA2034 standard of 40-60 for the ceiling reflections is a good spec. Doing the geometry on listening distances of 9-15ft, and ceiling heights of 8-10ft, those fall right in the 40-60 degree range. I do think they should go a bit lower for the floor reflection though.
You do have a narrower vertical sweet spot, but I only do critical listening sitting in that sweet spot, so I consider it a reasonable tradeoff to have potentially better sound for critical listening, even if not so much while I walk around the house.
You do have a narrower vertical sweet spot, but I only do critical listening sitting in that sweet spot, so I consider it a reasonable tradeoff to have potentially better sound for critical listening, even if not so much while I walk around the house.
Nearfield - I for example have a nearfield situation with my rear speakers in my living room. You have it on a working desk/speaker setup.
And it reveals problems which are masked from bad rooms - but as we all try to get good rooms ...
Different goals. Even distribution in the room or optimisation at the sweet spot. One has to die one death.
With my experience I take the first, but as long as I didn't built some prototypes and did a meaningfull listening session ... OK, I will anyway when I find time. ;-)
And it reveals problems which are masked from bad rooms - but as we all try to get good rooms ...
Different goals. Even distribution in the room or optimisation at the sweet spot. One has to die one death.
With my experience I take the first, but as long as I didn't built some prototypes and did a meaningfull listening session ... OK, I will anyway when I find time. ;-)
A coaxial will rarely have the tweeter within a quarter wavelenght at the XO frequency since the wavelengths are so short. So you still have an XO right where the ear is most sensitive.
A WAW uses the fact that at the XO the wavelengths are long, and one can actually acheive the end goal of a coax without the physical complications. And it gets the sharing of musical energy much closer to even as far as octaves covered.
dave
A WAW uses the fact that at the XO the wavelengths are long, and one can actually acheive the end goal of a coax without the physical complications. And it gets the sharing of musical energy much closer to even as far as octaves covered.
dave
I'm going to do that direct comparison soon, since this method is new to me too.
At the expensive high fidelity end perhaps although it is hard to see it as much of an issue for informed users. At the budget end it enables driver design to be straightforward leading to cheap prices and decent performance 15-30 degrees off-axis. So the $50 SB Acoustics 6" coaxial looks a good value driver whereas the $500 SEAS 6" coaxial rather less so.
At the designed off-axis listening position or listening on-axis?
I've listened to a number of highend fullrange designs at Rocky Mountain Audio Fest over the years. Including some with Voxativ, MA, Fostex drivers. They do sidestep some common multi-way issues, but there was never any doubt that the treble was always more unrefined than a good dome, IMHO.
Lets dont forget we have anytime the option to crosscheck our flawless stuff outdoors!
Just stumbled over this video , checkout the music from a BIPOL speaker at the end starting at 31:45sec :
And here the description link video , same song/band but from a CD source :
Just stumbled over this video , checkout the music from a BIPOL speaker at the end starting at 31:45sec :
And here the description link video , same song/band but from a CD source :
How do you come to that conclusion? 1/4 wavelength at 2kHz is 43mm. The acoustic centers of a coax mid and high driver are EASY in this range.
What's a WAW?
Really looking forward how is your impression at the listening seat compared to all over the room. And if there is a difference in how "pointy" the speaker appears (maybe mono listening) at large and small distance.
WAW= woofer assisted wideband, the kind of loudspeaker Dave is specialized in.
About coax yes in small diameter and with dome most of them cross in the 2/4khz range. Use bigger diameter and no dome and you can go an octave lower where there is less issue in my opinion. And it depend of the kind of xover you implement too, some are easier to spot than others.
About d'Apollito it really depend of implementation: with a typical dome it is difficult to implement in my experience as physical dimension of drivers are in the 'wrong range' wrt to freq of xover. Go bigger and it's way easier to integrate well.
That said as it was designed to offer a kind of vertical directivity control as a first objective it offer an optimal window.
About coax yes in small diameter and with dome most of them cross in the 2/4khz range. Use bigger diameter and no dome and you can go an octave lower where there is less issue in my opinion. And it depend of the kind of xover you implement too, some are easier to spot than others.
About d'Apollito it really depend of implementation: with a typical dome it is difficult to implement in my experience as physical dimension of drivers are in the 'wrong range' wrt to freq of xover. Go bigger and it's way easier to integrate well.
That said as it was designed to offer a kind of vertical directivity control as a first objective it offer an optimal window.
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