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Eminence Delta Pro 18 A in prism sealed 150 liters
Eminence Delta Pro 18 A in prism sealed 150 liters
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Old 14th February 2019, 08:58 PM   #101
academia50 is offline academia50  Argentina
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Quote:
Originally Posted by WaVeInFoRm View Post
...........

A diagram could explain well. But im too lazy.
Do not worry, I perfectly understand what you want to explain.
I currently raise or lower the volume and EQ of the plate amplifier to achieve it.
Thank you for your comments.
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Old 15th February 2019, 03:04 PM   #102
academia50 is offline academia50  Argentina
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The work is delayed, it has rained a lot to work abroad.
Waf has rebelled and forced to remove my tackle so they have gone to the sink waiting for the weather to improve....
So I have made some measurements in situ of the speaker. These are the actual dimensions, for obvious reasons, I prefer to use 18 inches, equivalent to a speaker overall diameter of 45.8 cm.


The work is delayed, it has rained a lot to work abroad.
Waf has rebelled and forced to remove my tackle so they have gone to the sink waiting for the weather to improve.
So I have made some measurements in situ of the speaker. These are the actual dimensions, for obvious reasons, I prefer to use 18 inches, for the use of the calculator equivalent to a speaker diameter of 45.8 cm.
(I insist that it is created to put that value, and the result will be approximate)
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File Type: jpg IMG_20190214_113441.jpg (535.0 KB, 123 views)
File Type: jpg IMG_20190214_111859.jpg (536.9 KB, 124 views)
File Type: jpg IMG_20190214_113343.jpg (740.4 KB, 121 views)
File Type: jpg IMG_20190215_123926.jpg (522.4 KB, 117 views)

Last edited by academia50; 15th February 2019 at 03:08 PM.
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Old 17th February 2019, 11:40 AM   #103
academia50 is offline academia50  Argentina
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Quote:
Originally Posted by WaVeInFoRm View Post

I did notice it sky rockets the diagram displacement so It might be better left out.

Hi WaVeInFoRm, this question is unanswered.....
You could explain to me what you mean, please, you have me intrigued !

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Old 17th February 2019, 12:04 PM   #104
WaVeInFoRm is offline WaVeInFoRm
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Join Date: Dec 2011
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well. any means to create more sound at lower frequency will result in more cone motion. be it equalizer or compactor, I Know with a smallish box you will need more amp to move the cone as the frequency lowers. I presume but do Not know if the same apples for using a capacitor. somebody else can answer That one...

so it might Not be better left out. if it can somehow allow the cone to move more at lower frequancys with less power that it would take to move the cone more at lower frequancys with a dsp/equaliser and the extra amplifier power. (to level the response)

At a guess, the power from the amp you need to move the cone for a given volume or output level at saaay 30 hz will be the same regardless of if you use dsp or a capacitor to fix and level the responce, as it is caused by physics. the resistance of the vacuum of the chamber the speaker is housed into. that must be over come with more amplification than had you built the boxes abit bigger

the question is... (for the professionals...........)

can you get the driver to xmax in 150l and still be within its power handling?


if so. what is the best way to ammend the responce? so it playes uniformly. is it to boost the lower notes (or diminish the higher range). or is it to use a capacitor to alter the signal response? i dont know enough but I sence the capacitor is sorta working like a equalizing circuit for the woofer to reject more hight frequency information than Lower frequency information. someone should clarify for you,
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Old 17th February 2019, 03:42 PM   #105
academia50 is offline academia50  Argentina
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Join Date: Jan 2013
Quote:
Originally Posted by WaVeInFoRm View Post
well. any means to create more sound at lower frequency will result in more cone motion. be it equalizer or compactor, I Know with a smallish box you will need more amp to move the cone as the frequency lowers. I presume but do Not know if the same apples for using a capacitor. somebody else can answer That one...

so it might Not be better left out. if it can somehow allow the cone to move more at lower frequancys with less power that it would take to move the cone more at lower frequancys with a dsp/equaliser and the extra amplifier power. (to level the response)

At a guess, the power from the amp you need to move the cone for a given volume or output level at saaay 30 hz will be the same regardless of if you use dsp or a capacitor to fix and level the responce, as it is caused by physics. the resistance of the vacuum of the chamber the speaker is housed into. that must be over come with more amplification than had you built the boxes abit bigger

the question is... (for the professionals...........)

can you get the driver to xmax in 150l and still be within its power handling?


if so. what is the best way to ammend the responce? so it playes uniformly. is it to boost the lower notes (or diminish the higher range). or is it to use a capacitor to alter the signal response? i dont know enough but I sence the capacitor is sorta working like a equalizing circuit for the woofer to reject more hight frequency information than Lower frequency information. someone should clarify for you,
Thanks, now I understand what you mean. I hope so, (highlighted in bold) although I have not had much luck in this regard, and I tried to make them smile a little but it does not work ... this is a too serious forum! I have some sims to answer some of your points, then upload them, the limitation in Xmax 6.7 mm seems to be an insurmountable obstacle, but Xlim is 15 mm, and according to my hearing level in my room I do not think it reaches that point. Anyway, I will tell you that if the result is not satisfactory, I will add tuned ports as Eminence suggests for this speaker and solved the problem. I do not think that I need REW, nor DSP, for me it is more than enough the level reached by my system in sound quality, in my particular listening conditions.
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Old 17th February 2019, 07:30 PM   #106
WaVeInFoRm is offline WaVeInFoRm
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Join Date: Dec 2011
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two 18 inch drivers at 6.7mm at 25 hz is reasonable enough. the thing is getting the driver to play 6.7mm at 25hz and with how much power.

The main thing is to bring down the far louder output in the higher bass (steep responce curve) to = Shallow of flat responce curve.


so if, for say your 100db at 25hz and 110 at 40hz and 125 at 80

you need to find a way to make it... 100db at 25hz 100db at 40hz 100db at 80

of corse it does not haaave to be wholey flaat, a gentle rising responce would be fine.


and there is also room gain to consider,

so for say... if the responce curve is like half a mounting. you need to chop of the top of the mounting so its even at all frequancys. then you will still get a decent enough output across the range with 2 18 inch drivers with 6.7 mm xmax and it sound good too.

what you need to figure, is how much power is needed to get to 6.7mm at (for say) 25hz in 150liters, and is it within the drivers power handleing capability. should be ok at a guess. but the resonance curve Is steep and I do recommend some active equalization to solve that and make it a good subwoofer set.


Quick example picture portraying what I mean,

not saying 100db is the max could be 110 or such. This is just to illustrate


one lazy way would be to wack a 21band eq inline before the amp and then use that sorta in reverse to the speakers curve, at that range of the frequancy responce. should do the trick

(u just turn down aaal the freq above 100hz then you rise each one abit more in a curve untill at 20hz its +12db where as 100hz is at -12db and use that before the crossover in the amp and the amp itself. I hope I am explaining that last bit well enougth. you can get the types they use in rack mounts easy enougth and they have plenty of bands to play with, all you need to do is reshape the responce curve. so for say it was like this

20hz 40hz 80hz 120hz

u turn 125hz and all above to about -12

then 80hz would be -6

40hz +6

20hz +12

about that...... but thats the bassic idea portrayed anyway.
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Last edited by WaVeInFoRm; 17th February 2019 at 07:57 PM.
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Old 17th February 2019, 08:09 PM   #107
WaVeInFoRm is offline WaVeInFoRm
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31 band then..

see, you bassically set the eq as a inverse flipped version of the response curve and that will levelize it.

if thats enouth eq... im not sure. 24db! Is a fair amount. should be. may not even need Thaat much in which case you alter it accordingly.
then wack the eq infront of the amp. and still use in inamp crossover and it should be fine.

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Old 17th February 2019, 08:24 PM   #108
WaVeInFoRm is offline WaVeInFoRm
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This would also provide you with the option of when listening louder to boost the lower frequency's less and turn up the higher ones somewhat and have more usable output for say 40hz - 100hz

to me 25hz is practical to work with or 30 as you will still get some output to 20 but if u leveled it all flat to 20 I sence you lose tooo much spl. but a eq would provide you room to play so where you opting for a flat responce or rising slope you Can do that. the output of the system will be volume limited by displacement at chosen cut off


the sim for your driver/box if its 96db at 20, 100db at 25hz it is 113db at 100hz



so working with 25hz, on the equalizer you would simply turn 100hz down 13db on the equalizer etc I tired now. screen fatigue

I hope my example helps. in actuality you dont need to equalize it Thaat much. But Using a equalizer I would Highly recommend for this design of yours.

Last edited by WaVeInFoRm; 17th February 2019 at 08:27 PM.
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Old 17th February 2019, 08:31 PM   #109
academia50 is offline academia50  Argentina
diyAudio Member
 
Join Date: Jan 2013
Quote:
Originally Posted by WaVeInFoRm View Post
two 18 inch drivers at 6.7mm at 25 hz is reasonable enough. the thing is getting the driver to play 6.7mm at 25hz and with how much power.

The main thing is to bring down the far louder output in the higher bass (steep responce curve) to = Shallow of flat responce curve.


so if, for say your 100db at 25hz and 110 at 40hz and 125 at 80

you need to find a way to make it... 100db at 25hz 100db at 40hz 100db at 80

of corse it does not haaave to be wholey flaat, a gentle rising responce would be fine.


and there is also room gain to consider,

so for say... if the responce curve is like half a mounting. you need to chop of the top of the mounting so its even at all frequancys. then you will still get a decent enough output across the range with 2 18 inch drivers with 6.7 mm xmax and it sound good too.

what you need to figure, is how much power is needed to get to 6.7mm at (for say) 25hz in 150liters, and is it within the drivers power handleing capability. should be ok at a guess. but the resonance curve Is steep and I do recommend some active equalization to solve that and make it a good subwoofer set.


Quick example picture portraying what I mean,

not saying 100db is the max could be 110 or such. This is just to illustrate


one lazy way would be to wack a 21band eq inline before the amp and then use that sorta in reverse to the speakers curve, at that range of the frequancy responce. should do the trick

(u just turn down aaal the freq above 100hz then you rise each one abit more in a curve untill at 20hz its +12db where as 100hz is at -12db and use that before the crossover in the amp and the amp itself. I hope I am explaining that last bit well enougth. you can get the types they use in rack mounts easy enougth and they have plenty of bands to play with, all you need to do is reshape the responce curve. so for say it was like this

20hz 40hz 80hz 120hz

u turn 125hz and all above to about -12

then 80hz would be -6

40hz +6

20hz +12

about that...... but thats the bassic idea portrayed anyway.

Well, I have enough to study your observations, thanks for that.
In my post 25 onwards there are the simulations that I have obtained with WinIsd, there are some that I do not understand, for example the Cone excursion is just a straight line at the 6.7 mm point, something must be wrong there ..
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Old 17th February 2019, 08:38 PM   #110
academia50 is offline academia50  Argentina
diyAudio Member
 
Join Date: Jan 2013
Quote:
Originally Posted by WaVeInFoRm View Post
This would also provide you with the option of when listening louder to boost the lower frequency's less and turn up the higher ones somewhat and have more usable output for say 40hz - 100hz

to me 25hz is practical to work with or 30 as you will still get some output to 20 but if u leveled it all flat to 20 I sence you lose tooo much spl. but a eq would provide you room to play so where you opting for a flat responce or rising slope you Can do that. the output of the system will be volume limited by displacement at chosen cut off


the sim for your driver/box if its 96db at 20, 100db at 25hz it is 113db at 100hz



so working with 25hz, on the equalizer you would simply turn 100hz down 13db on the equalizer etc I tired now. screen fatigue

I hope my example helps. in actuality you dont need to equalize it Thaat much. But Using a equalizer I would Highly recommend for this design of yours.
Thanks again, when I hear the final result, I'll see if I need a professional equalizer, instead of the simple cut-off frequency selector on the board amplifier :RE
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