Simulations with VituixCAD seem to show that the closest spacing may not provide the best overall power response.
interesting.
Simulations with VituixCAD seem to show that the closest spacing may not provide the best overall power response.
I wonder why Troels Gravesen thinks he can design a better crossover than the engineers at Yamaha??
Oh yeah he sells them for 900 Euros the pair.![]()
The NS1000 was an exceptional loudspeaker at the time, and not embarrassing even now. See Figure 18.3. The only problem was that they were designed for a flat sound power target, so they were slightly bass shy - turn up the bass and/or turn down the treble for better balance. The NS-10 was also designed for flat sound power, and in a two-way that was most regrettable - although inexplicably many recording engineers got sucked into what can only be described as a "fashion". Truthfully it was an Auratone with more bass. The designer visited me at the NRCC and went away swearing never to do it again. He didn't, and subsequent Yamaha monitors were flat on axis. Section 12.5.1 in the 3rd edition discusses this and shows measurements.
To be fair he doesn't make a big thing about it and when I read his article years ago I decided the measurements showed it didn't make enough difference to be worth it (for me)I wonder why Troels Gravesen thinks he can design a better crossover than the engineers at Yamaha??
Oh yeah he sells them for 900 Euros the pair.![]()
If they pull off the same shot they did with thier tweeters, these will be REALLY good, and REALLY expensive.Bliesma domes should be out this year.
This kinda brings up the point: mid domes are for far-field speakers. You do want drivers close together if you want to sit close to the drivers for near-field.Simulations with VituixCAD seem to show that the closest spacing may not provide the best overall power response. According to VituixCAD developer something between 1.2 and 1.5 fc wavelength appears to provide the best power response while 0.5 to 0.7 provides the worst case result.
With your assumption of 3000hz, 15cm (11.5cm x 1.3) should be a preliminary target, hence large physical diameter is not necessary a issue even if small diameter means more spacing freedom.
Near field has different requirements because power response has not much effect and early reflections should be avoided. So very short c-c or coaxial would be better.
- kimmoVituixCAD thread on diyaudio contains three examples with real life data and simplified theoretical study about c-c = 1.2 x wave length concept. It's actually quite common in practice. Traditionally XO frequencies 2.5-5 kHz were common, and sound of those speakers was typically smoother and more tolerable than (modern) low XO point. So I'm not trying to invent anything new or provoke. Just giving an answer why some sound features were better in the past; no blood from ears while listening 80s' Gary Moore or Iron Maiden.
Common (modern) opinion/statement is that c-c should be as short as possible. With "normal luck" it hits c-c = 1/2 wave length at XO which causes the worst possible power dip and balance break with conventional unidirectional box speaker. Also risk of power bump above XO point increases with conventional tweeters without wave guide. c-c = 1/4 wave length at XO is just an utopia - worthless to mention for other than XO between mid and woofer, or woofer and small full-range as a tweeter.
That sounds perfect for a small tweeter for wide dispersion and a broad sweet spot:I stopped using midrange drivers a long time ago because the lower crossover point from the woofer to the midrange driver was in too critical a frequency range within the audio band, and was always too easy for me and others to hear as a discontinuity, and find distracting. I am a believer in the expression that "there is no crossover, like no crossover", but unfortunately every single full range driver that I have ever heard fell well short of expectations, and had too many discontinuities in the highs, nor enough bass - and ended up adding subwoofers crossed over fairly high plus add-on super-tweeters to sound OK - but the overall response of the full range driver was still quite bumpy.
Accordingly, in my own design work a compromise evolved. I began to use stereo subwoofers crossed over below 80Hz, which is a non-critical crossover point to the ear, and then I crossover the mid-woofer in the main speakers to the tweeter in the main speakers higher than normal at around 3.5KHz, which is again a better place for a crossover point. Not having any crossover point in the critical center band (80Hz to 3.5KHz) has been a great improvement in my opinion. Today there are an abundance of mid-woofers that I have found can cover this range very nicely.
Off-the-shelf 3" domes, I can only think of two currently available. One is the $107 Scan Speak D7608/92000-10 (which needs a sealed chamber in the cabinet as it's open back), and the other is the $500+ Volt VM752. You used to be able to get the ATC SC75-150, but no longer. As far as I know the ATC is the only dome you could actually comfortably cross around 3-400hz but I am also not super well versed.DIY builders enjoy fairly good availability of domes in the 2" range, whereas off-the-shelf 3" domes are less common.
This claimed effect has now been brought up at least three times on ASR, in three different threads. As such it seems likely that this will occur henceforth, each and every time that anyone says anything about the vertical spacing of drivers. Perhaps there should be a thread on ASR dedicated expressly to this effect, not to vituixCAD generally, but to this one effect specifically. It is highly desirable with something like this for the underlying assumptions to be clearly identified, at least, and thus far this has not happened, at least not on ASR, to the best of my knowledge. As for the provided link to the vituixCAD thread on diyAudio, it is not remotely realistic for anyone to be expected to read through that 316-page thread to try and figure out exactly what this claim even is.
Yeah, his thread is a long mess to try to pull info out. There are sims of real speakers in there that do show what he is talking about. I've seen it, but don't have the links handy. If I can find the info I'll post it in the vert. thread and here.
The claim is easy to see in vcad. Model two drivers in vcad, make an XO, and play with the v. spacing. The DI will change.
We mess with the X moving speaker from the walls. We mess with the Y when we position the tweeter in space. Is it so odd to position the drivers for a sphere at Z in space? This is my newbie view of it. Many of you have forgotten more than I know so let me know if this sounds wrong.
TMK, Morel uses underhung arrangements in their dome drivers.
I have a love for mid domes, and have several awaiting designs. They just do some things very right.
My favorites include the ATC and derivatives, Usher 9845, and Morel MDM55 and EM1308.