Well, what's stopping you from “investigating more” right now? All the principles you need are already described in this thread. Everything I do is consistent with them.
If you want my trade secrets so that you can copy what I do, I'm afraid the answer is “no”. DIYers are no more entitled to my trade secrets than anyone else is.
Just use your own ingenuity to apply the principles in this thread, taking your system and room and priorities into account, and don't worry about the specifics of what I do.
Last edited:
Ha! I don't want to copy, just interested, nevermind Mr. Hypocrite
I don't think that's a fair judgement. If you invest research to make it into a proffitable concept, one should be allowed to keep some of it to yourself to maintain your business. There are other similar projects documented on here, some with close to full disclosure that should give enough detail and inspiration for anyone that wants to try it for themselves.
Not that I am completely happy by not getting to know the details behind that relatively small box and how it is managing to maintain the 10 ms delay over the entire bandwidth it's playing (said to be done by beying bounced off of the ceiling, I would expect it to behave more like an omni source at low frequencies. It's difficult to get that kind of directivity in such a small package).
I'd love to see some measurements and data on that. But I can understand the reasons behind it if we do not get to see it.
Not that I am completely happy by not getting to know the details behind that relatively small box and how it is managing to maintain the 10 ms delay over the entire bandwidth it's playing (said to be done by beying bounced off of the ceiling, I would expect it to behave more like an omni source at low frequencies. It's difficult to get that kind of directivity in such a small package).
I'd love to see some measurements and data on that. But I can understand the reasons behind it if we do not get to see it.
Last edited:
Everything I copied about the SoundLabs was obvious and public domain, their radiation pattern no trade secret. I wrote to Roger West and told him in advance of my intention to copy those aspects of his design, and he considered it a sincere form of flattery.
Do you have questions about something I said in this thread that wasn't clear? Is there some aspect you'd like to know more about? If you really are interested, I don't want to push you away over an internet forum squabble.
It is an omnidirectional source at low frequencies. The upper-mid and high frequencies are much more important for localization, and the LCS section is large enough to have good directional control down to about 1.5 kHz. But in my systems it is also positioned BEHIND a wide main speaker, which helps to block its sideband energy from early arrival at the listening area, effectively extending directional control down a bit lower.
It's not in the spirit of diy audio, it's more of a sales pitch, it should be in the commercial section, just my judgement of course
Then why would you want to know more about something that you dismiss as "more of a sales pitch", and belonging in the commercial section?
I presume you said that because you wanted to get in one more insult, but that you really are interested, because your next post raises a good question:
Here are five things to be aware of:
1. The power response of the LCS section is what matters, not the "on-axis" response. So you should make your measurements and design choices accordingly.
2. The LCS section will interact with the floor and (presumably nearby) wall, and that should be taken into account, to avoid a "chesty" coloration.
3. The power response of the LCS section should generally track the first-arrival sound of the main speakers fairly closely. Imo you want a little bit less top end from your LCS speakers, as heard at the listening position (this being an approximation of the air-induced attenuation of shorter wavelengths as they travel long reflection paths in a concert hall).
4. Ime it's not a bad idea to build some top-end "tilt" adjustability into the LCS section, as some trial-and-error may be called for.
5. As an alternative to #3, you might tailor the response of the LCS section to "zig" where your main speakers have an off-axis "zag".
Also, this is not about spectral content, but the ability to dial in the loudness of the LCS section relative to the mains is useful.
Last edited:
Ok, thank you, Linkwitz was in two minds as to the requirement for the same spectral content in the late reflections as the direct sound, eventually he and others have come to consider they should be the same. Attenuation of the higher frequencies could certainly create the illusion of a larger space, so long as one keeps one's eyes closed....
You're welcome!
I can see arguments either way, and the ideal (from the standpoint of timbre at least) may depend somewhat on what the main speakers are doing off-axis in their top octave or so. If their off-axis response is nose-diving up there, then we may want the LCS section's power response to hold up fairly well up there.
I can see arguments either way, and the ideal (from the standpoint of timbre at least) may depend somewhat on what the main speakers are doing off-axis in their top octave or so. If their off-axis response is nose-diving up there, then we may want the LCS section's power response to hold up fairly well up there.
In my setup (the one using BMR drivers behind the main speakers driven by DSP delay), it seems to work best with the higher frequencies extended all the way out. But that's to my ears, and they're a little over 65yrs old now, so might be compensating perhaps? The main speakers (SEOS based synergy horns) have pretty good off-axis response as well, though of course still generally falling at higher frequencies.
Can you tell us some more about your use of BMR drivers please? Is it similar to the LCS setup? Are you finding it perceptually expands the soundstage? What sort of massaging of the signal do you do in the DSP? Have you compared to normal drivers in the same role?
Hi mmerrill99,
There is a thread about it at Ambience tweeters using small BMR drivers.
Since then, I've gone to scrambling the phase using FIR at HF (I think that's better, but hard to say, might be just expectation) and about 20msec delay. The spectrum is set so the energy from the BMRs starts around 1kHz now and is relatively flat up through the highest octave.
The main effect is that it makes the room feel larger (it is a small room) and, more importantly, it makes the sound more 'live' -- meaning that it sounds to me more like I'm in a room where that music is being performed (rather than just where some sound is coming out of a couple of speakers). I've gotten a few jabs online (but not by anyone who has heard it!) that this is going back to the BOSE 901 effect. But it isn't, IMO. There is still a precise and clear image from the controlled directivity early arrival (unlike the vague effect of 'sound everywhere'), and recordings don't all sound the same from a hardwired sound effect being added. Probably because of the long delay before the ambience comes in, which still allows the first arrival to set the scene while the delayed provides the energy from the sides (that would always be there in some form with a real performance, but hardly ever in in-room 'stereo').
There is a thread about it at Ambience tweeters using small BMR drivers.
Since then, I've gone to scrambling the phase using FIR at HF (I think that's better, but hard to say, might be just expectation) and about 20msec delay. The spectrum is set so the energy from the BMRs starts around 1kHz now and is relatively flat up through the highest octave.
The main effect is that it makes the room feel larger (it is a small room) and, more importantly, it makes the sound more 'live' -- meaning that it sounds to me more like I'm in a room where that music is being performed (rather than just where some sound is coming out of a couple of speakers). I've gotten a few jabs online (but not by anyone who has heard it!) that this is going back to the BOSE 901 effect. But it isn't, IMO. There is still a precise and clear image from the controlled directivity early arrival (unlike the vague effect of 'sound everywhere'), and recordings don't all sound the same from a hardwired sound effect being added. Probably because of the long delay before the ambience comes in, which still allows the first arrival to set the scene while the delayed provides the energy from the sides (that would always be there in some form with a real performance, but hardly ever in in-room 'stereo').
dunno. In my philosophical mind games about it, the idea of mixing waveguide-like sharp image projection with ambience is appealing. Minimizing early reflections would seem to be part of that. But that doesn't mean that cone/dome/ribbons as mains wouldn't still benefit. The time delays might be the bigger part of it, who know? Duke's system seems to emphasize directivity on the ambient radiators to keep their overall delay to the listener longer. Perhaps the ambient drivers should be some 12" waveguides (aimed to the side walls or ceiling) instead?
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.