Controlling Xmax of loudspeakers |
Post Reply | Page <123 |
Author | ||||
Elliot Thompson
Old Croc Joined: 02 April 2004 Location: United States Status: Offline Points: 5172 |
Post Options
Thanks(0)
|
|||
This is the problem with simulators. They never co-relate to the impedance results using ARTA and/or REW. This is due to the fs, VAS in addition to Qts of the driver changes once it is placed in the box. If you measure the TS Parameters of a driver in free air versus the Manufactures TS Parameters you will attain different results on the impedance curve. If you measure TS Parameters in the box versus the simulated TS Parameters (Measured or Manufacture) in the box, you will attain different results on the impedance curve. Simulators are like Protein Powder. It may appear to offer all the necessary nutrients in terms of proteins however Protein Powder cannot give you the same results as eating real food supplied with protein. The more I measure loudspeakers, the more I realise Simulators are a good starting point to familiarise yourself with loudspeaker design. However, at some point you will need to start literally measuring loudspeakers to get the in depth analysis on the results. We also need to take into consideration exceeding the Xmax
does not damage the driver. It is exceeding the Xmech limit ( Best Regards, |
||||
Elliot Thompson
|
||||
Crashpc
Registered User Joined: 26 February 2008 Location: Czech Republic Status: Offline Points: 463 |
Post Options
Thanks(0)
|
|||
Eeee I don´t think so. Not really. It is doable, but it would bring too much trouble that it is probably not worth. I was thinking about this before. Firstly, If you move the speaker below its usable pass band, it doesn´t mean there is not significant SPL output. That alone might cause some trouble. My 29-33Hz tuned bins shake the ceiling at 14-25Hz, even though, there is not much sound to hear. Secondly, if you du it in regular music, you offset the cone (irregular fashion makes this even worse), so you lower your cone excursion range for your usable pass band. Then You need to put significant amount of power to the coil to move it, yet you don´t have any usable sound from it. Many enclosures have impedance minimums under the HPF subsonic, so that would also add another heat. Then cooling the cone with low frequency is less efficient. You really WANT to cool it down at lets say 40+Hz. That is efficient. You still could solve SOME of these problems, but at a cost of advanced processing and programming, which would rather add so much price for an individual, that it is lightyears easier to just buy better speaker or build multiple bins... |
||||
Nikon and Canon people should not be married to each other. Why did you let this happen?
|
||||
gen0me
Young Croc Joined: 20 February 2016 Location: UK Status: Offline Points: 999 |
Post Options
Thanks(0)
|
|||
It doesnt have to sound. It has to move. But there might be something about colorizing lower frequencies with harmonic oscilator resonance frequency.
I dont see any cones in this. If in the music there is already such material then there are no higher bass frequencies. Simply on studio mix level under 40hz bass means giving up on any higher notes.
|
||||
I appreciate every like :)) https//www.facebook.com/genomesoundsystems
Mixes: https://www.mixcloud.com/gen-ome/ |
||||
Crashpc
Registered User Joined: 26 February 2008 Location: Czech Republic Status: Offline Points: 463 |
Post Options
Thanks(0)
|
|||
Elliot: Never say never. WinISD simmed my 21DS115 box within usable passband of 25-100Hz VERY acurately. Both phase and impedance. It is not THAT bad always. On the other hand, Hornresp failed in this regard. It was little more accurate in frequency response graph though. Yet there are things which are not being simmed, and also very different things happen with large signals, which are used most often for real work with the speaker. Of course... I hope nobody ever recommends a simulator or protein powder as a final decisive factor/solution. Of course cone excursion is related to the impedance, no doubt. But it is not shackled to it. I can present it on my development box too. There are many aspects playing the role in the cone excursion, and accoustical impedance is only one of these, altering the speaker impedance. Not that you didn´t have a good point, it is just not that black and white. |
||||
Nikon and Canon people should not be married to each other. Why did you let this happen?
|
||||
Crashpc
Registered User Joined: 26 February 2008 Location: Czech Republic Status: Offline Points: 463 |
Post Options
Thanks(0)
|
|||
Eeee, I don´t think you understood. It doesn´t have to sound, but IT DOES. And that is quite a problem. In order to not make it do sounds, you need to move the speaker waay way down under the pass band. And it usually means a lot of power due to the low impedance. That is contraproductive, because at low frequencies, cooling is not that effective.
Any cones? I don´t understand here. If you cool down your speaker by cone movement, and the cone is offset by that movement, and audio signal comes to the speaker in phase at that moment, the cone will push even further. But as the cone was in offset position already, and the speaker is limited by Xmax, or power, you leave very little cone excursion available for usable content, because you used it for the cooling. It is quite "rare", that there is musical sub 25Hz material in the music. Especially for PA. But I would not risk thinking that there is nothing all the time. That might end up in a catastrophy again.
Edited by Crashpc - 31 December 2018 at 8:58am |
||||
Nikon and Canon people should not be married to each other. Why did you let this happen?
|
||||
gen0me
Young Croc Joined: 20 February 2016 Location: UK Status: Offline Points: 999 |
Post Options
Thanks(0)
|
|||
It wont happen. You cant have both type of basses simultaneously in the mix. One bassline near 0db fulfills the hole mix. And if there comes the kick - bass is sidechained. What were your port input parameters for winisd and hornresp?
Edited by gen0me - 31 December 2018 at 9:42am |
||||
I appreciate every like :)) https//www.facebook.com/genomesoundsystems
Mixes: https://www.mixcloud.com/gen-ome/ |
||||
gen0me
Young Croc Joined: 20 February 2016 Location: UK Status: Offline Points: 999 |
Post Options
Thanks(0)
|
|||
Even going smarter you can make generator 20hz that is sidechained under djs output and delayed right way, with right release time.
Although the difference in all mechanical ts would be ridiculous at the end of the show. Edited by gen0me - 31 December 2018 at 9:57am |
||||
I appreciate every like :)) https//www.facebook.com/genomesoundsystems
Mixes: https://www.mixcloud.com/gen-ome/ |
||||
odc04r
Old Croc Joined: 12 July 2006 Location: Sarfampton Status: Offline Points: 5483 |
Post Options
Thanks(0)
|
|||
Yep. TS properties are just a starting point, they describe a simplified small signal lumped linear model after all. It would be unrealistic to expect anything else. But as we say in the UK (sometimes), still better than a kick in the balls. A driver's TS parameters do not change when placed in an enclosure, the net sum (of e.g. compliance) is modified with respect to the properties of the enclosure such as a sealed enclosures volume compliance adding to the drivers compliance to shift up the original Fs and Qts, but the drivers individual properties should not change at small signal levels. If you were to construct a full circuit model and decompose the total system impedance plot to it using regression you'd see that, although there is a problem in that some of the model properties will inevitable be able to compensate for others. There is a good read on the subject here: http://www.volucres.fr/AudioHighEnd/resources/SciAudioBoxEn/Vented-box-parameter.pdf It would be a sensible approach to assume that there will be up to 10% deviation in free air TS from any manufacturers published specs to allow for manufacturing variation imo, especially Fs which is subject to multiple manufacturing variations that could pull it either way. Edited by odc04r - 31 December 2018 at 10:54am |
||||
Crashpc
Registered User Joined: 26 February 2008 Location: Czech Republic Status: Offline Points: 463 |
Post Options
Thanks(0)
|
|||
gen0ne: Not that it wouldn´t be doable, but it is very bad way to do that... |
||||
Nikon and Canon people should not be married to each other. Why did you let this happen?
|
||||
Post Reply | Page <123 |
Tweet |
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |