|
Post by frednorc on Nov 23, 2019 11:35:13 GMT 10
Hi Mark, Have you tried a schumann generator? I tried a cheapy off ebay and it did do something but havent gone back to it as yet.
The Bassbox is passive as I understand it and not powered so different mechanism.
Let me know what you want for it. I may be up for a play!
Cheers Mark
|
|
STC
Junior Member
Posts: 18
|
Post by STC on Nov 23, 2019 12:29:53 GMT 10
And now here is the Spectrogram with both the FEQ's on: View AttachmentBass energy is still there but seems a tad less density in the bass region. One repeatable phenomenon in the spectrograms that I have noticed is that the FEQ's increase the decay time by a small amount at higher frequencies. Interesting. Is it possible to measure the noise floor of the room under the following conditions:- 1) Room without your main system turned on. 2) FEQ is brought to the room but turned off. 3) FEQ turned on. Thanks.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 23, 2019 13:06:47 GMT 10
Hi Mark, Have you tried a schumann generator? I tried a cheapy off ebay and it did do something but havent gone back to it as yet. The Bassbox is passive as I understand it and not powered so different mechanism. Let me know what you want for it. I may be up for a play! Cheers Mark I haven't looked at the Bassbox to be honest. Since I bought the AVAA active bass trap I've settled on a solution to deal with room modes. Yes, I have one of the cheapy Ebay Scumann generators too. I've never really found it to do much. To be honest, I have no way of working out if it is working correctly. Perhaps the branded ones (like Acoustic revive) might be much more noticeablein their effects. I'll PM you about the FEQ
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 23, 2019 13:12:17 GMT 10
And now here is the Spectrogram with both the FEQ's on: Bass energy is still there but seems a tad less density in the bass region. One repeatable phenomenon in the spectrograms that I have noticed is that the FEQ's increase the decay time by a small amount at higher frequencies. Interesting. Is it possible to measure the noise floor of the room under the following conditions:- 1) Room without your main system turned on. 2) FEQ is brought to the room but turned off. 3) FEQ turned on. Thanks. Haven't tried those types of measurements but I could. Some thoughts and questions first though. 1) The noise floor in my room is about 45dB. That would be well above the noise floor of my stereo. I have to put my ear against the tweeter on my speakers to hear any hiss with the system on but not playing music. Are you perhaps referring to EMR "noise"? I can measure using the RTA but I'm only going to get acoustic noise. 2) Do you mean, bring them into the room with the stereo off and the FEQ's off? 3) Again, FEQ turned on, system off? Mark
|
|
STC
Junior Member
Posts: 18
|
Post by STC on Nov 23, 2019 13:28:33 GMT 10
Is it possible to measure the noise floor of the room under the following conditions:- 1) Room without your main system turned on. 2) FEQ is brought to the room but turned off. 3) FEQ turned on. Thanks. Haven't tried those types of measurements but I could. Some thoughts and questions first though. 1) The noise floor in my room is about 45dB. That would be well above the noise floor of my stereo. I have to put my ear against the tweeter on my speakers to hear any hiss with the system on but not playing music. Are you perhaps referring to EMR "noise"? I can measure using the RTA but I'm only going to get acoustic noise. 2) Do you mean, bring them into the room with the stereo off and the FEQ's off? 3) Again, FEQ turned on, system off? Mark LF is hard to predict. Even the air conditioning hum could influence the measurements. My neighbors SUV cannot be heard when the car passes my house except in one of the bathroom with small opening where the LF from the exhaust gets amplified. Similarly, the FEQ could be emitting LF which would not be audible but the energy could affect higher frequencies by either cancellation or reinforcement. I thought it would be interesting to see if the presence of the FEQ somehow affect whatever energy in the room without your main system turned on. I have encountered similar equipment or perhaps the same during a demo several years ago. It did change the sound and I was very keen to understand them but never got one myself. So your measurement could prove something. Looking forward to those measurements. Thank you. ST
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 23, 2019 14:00:51 GMT 10
I'll get in early one day this week to the office, keep the A/C off and try these measurements.
|
|
STC
Junior Member
Posts: 18
|
Post by STC on Nov 23, 2019 14:09:33 GMT 10
I'll get in early one day this week to the office, keep the A/C off and try these measurements. Leave the air conditioning on and all others on except your system. Your NF includes them when listening.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 23, 2019 14:14:01 GMT 10
OK. Shall do.
|
|
|
Post by ROWUK on Nov 23, 2019 19:40:21 GMT 10
I agree that EVERYTHING makes a difference BUT to eat serious amounts of LF needs something bigger than this box (as LF is not even evenly spread throughout the room). My understanding of how rooms work is that we have a source of energy (the speaker) and the standing waves in the room created by the specific dimensions determine the nodes and intensity. The nodes themselves can be 20dB or more higher than the antinode. This means that if we have a room size corresponding to 40 Hz in one axis, 57 in another and the diagonals with 32Hz, the room modes will be those and their low order multiples. If we fill a room with helium or ozone, the speed of sound changes and thus the frequency wavelengths resonating.
If we do not electrically limit the speaker, the energy from the source remains the same. As we can only convert energy - not delete it, my question is where is the standing wave going? Normally with LF, we have to turn it into "heat" with damping. As we go up the frequency spectrum, we normally damp less and reflect more. What is happening at each LF nodal point and antinode? In my world bass response changes every centimeter moved.
There has to be a technical explanation for the spectrum analysis that you performed. I am convinced that blind listening tests are never definitive of anything. Lay people don't need to understand it but reliable results are engineered - if this truly works, someone knows the answer. At the SR site, there seems not to be a FEQ anymore. The LF solution at the site is called "black box" or Atmosphere. Their own description at the site is major BS as no external device can correct phase after the fact - the time that it takes for the signal to get to the box from the source would be a phase shift before the box can know what is in the room. What would this box do with open back speakers where we have 180° phase shift front to back and unpredictable phase shift to the sides?
I am happy for you, but I see no compelling reason to believe anything that they claim. My goal is to solve problems instead of apply bandaids. In small rooms. The solution in small, live rooms is to accept less LF extension or use at least 3 critically placed subwoofers to energise the room in a more advantageous way (as Geddes has documented). For the 2 grand that a blackbox costs, a lot can be accomplished in the room to make it more playback friendly.
Still, you show a physical difference - that comes from somewhere. Is less more? well that depends how the box can know that one frequency is more desirable and another not - and for what position in the room.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 23, 2019 20:42:51 GMT 10
I agree that EVERYTHING makes a difference BUT to eat serious amounts of LF needs something bigger than this box (as LF is not even evenly spread throughout the room). My understanding of how rooms work is that we have a source of energy (the speaker) and the standing waves in the room created by the specific dimensions determine the nodes and intensity. The nodes themselves can be 20dB or more higher than the antinode. This means that if we have a room size corresponding to 40 Hz in one axis, 57 in another and the diagonals with 32Hz, the room modes will be those and their low order multiples. If we fill a room with helium or ozone, the speed of sound changes and thus the frequency wavelengths resonating. If we do not electrically limit the speaker, the energy from the source remains the same. As we can only convert energy - not delete it, my question is where is the standing wave going? Normally with LF, we have to turn it into "heat" with damping. As we go up the frequency spectrum, we normally damp less and reflect more. What is happening at each LF nodal point and antinode? In my world bass response changes every centimeter moved. There has to be a technical explanation for the spectrum analysis that you performed. I am convinced that blind listening tests are never definitive of anything. Lay people don't need to understand it but reliable results are engineered - if this truly works, someone knows the answer. At the SR site, there seems not to be a FEQ anymore. The LF solution at the site is called "black box" or Atmosphere. Their own description at the site is major BS as no external device can correct phase after the fact - the time that it takes for the signal to get to the box from the source would be a phase shift before the box can know what is in the room. What would this box do with open back speakers where we have 180° phase shift front to back and unpredictable phase shift to the sides? I am happy for you, but I see no compelling reason to believe anything that they claim. My goal is to solve problems instead of apply bandaids. In small rooms. The solution in small, live rooms is to accept less LF extension or use at least 3 critically placed subwoofers to energise the room in a more advantageous way (as Geddes has documented). For the 2 grand that a blackbox costs, a lot can be accomplished in the room to make it more playback friendly. Still, you show a physical difference - that comes from somewhere. Is less more? well that depends how the box can know that one frequency is more desirable and another not - and for what position in the room. What technical reason do you propose? I understand how room modes work as well. I have a bit of experience with acoustics and room treatments. I understand that flies in the face of conventional physics. But I have measured it repeatedly. Funnily enough, when I did the same measurements to record the effects of passive bass traps, an active Bag End Bass trap and finally an AVAA active bass trap, in the same room with the same recording equipment, no one seemed concerned that there were any technical issues or that my measurements are in error. How much more compelling evidence do you need?
|
|
|
Post by ROWUK on Nov 23, 2019 23:13:15 GMT 10
I do not need any evidence. If the manufacturer can‘t even offer a plausible explanation, why should I bother? The level of bogus text at the website scares me off, to be honest. If in fact phase correction were possible, it would be measurable. A simple measurement with Holm Impulse would provide at least confidence that the claim were true
I do not doubt what you measured. To put it into perspective, I would have to measure the room at the „hot“ nodes and „dead“ antinodes first. Then try to figure out what part of the LF was actually reduced. Normally things too good to be true are exactly that. Energy has to go somewhere and this device is too small to store or dissipate that type of energy.
I still am interested in what the device physically does. Does the reduction come from out of phase LF? Is it a Bose Wave Radio in reverse? Musical instruments have harmonics, Some instruments do not have even multiples for harmonics (percussion for instance). Rooms only have even partials. Their strength depends on a lot of factors. how can any device tell the difference.
Sorry, I don‘t buy the concept. It is simply too far away from anything that makes sense to me.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 24, 2019 8:25:58 GMT 10
I do not need any evidence. If the manufacturer can‘t even offer a plausible explanation, why should I bother? Well given your stance, there is no point in us discussing this any further.
|
|
STC
Junior Member
Posts: 18
|
Post by STC on Nov 25, 2019 17:08:47 GMT 10
I do not need any evidence. If the manufacturer can‘t even offer a plausible explanation, why should I bother? Well given your stance, there is no point in us discussing this any further. I am still hoping that you would the measurements.
|
|
|
Post by ROWUK on Nov 27, 2019 17:52:28 GMT 10
I do not need any evidence. If the manufacturer can‘t even offer a plausible explanation, why should I bother? Well given your stance, there is no point in us discussing this any further. This is the biggest problem with an internet forum. Critical observation is attached to not winning. I do not see that this is an issue to win or lose. You measured a difference, that has to come from somewhere. Unfortunately static measurements do not tell us much of anything. We also have no idea about the LF resolution of your system. We also have no idea about standing waves in your room. We do not know if the device lump sum reduced LF, was selective about anything or if you measured some other artifact. As the website is pure BS - where is the base for discussion except to collect more details? I would have thought that as you dropped some serious coin for this device, you would be interested in what it really did and posted to share it.
|
|