Can't seem to hit lows even with the DD-1

[wew lad 5,000+ posts]

Smaller port, tuned lower, gonna have to sacrifice output or the upper end though

So a different box

 

[Papermaker85 5,000+ posts]

Smaller port, tuned lower, gonna have to sacrifice output or the upper end though
So a different box

Small port? Lower your tune the more port area you need to lower noise/resistance

 

[wew lad 5,000+ posts]

Small port? Lower your tune the more port area you need to lower noise/resistance

Bandwidth

Should of said port area to volume ratio for you

 

[Boomin_tahoe 5,000+ posts]

Bandwidth
Should of said port area to volume ratio for you

lulz. So he can understand it better. Classic.

 

[Papermaker85 5,000+ posts]

Bandwidth
Should of said port area to volume ratio for you

How does a smaller port equate to a wider bandwidth?

 

[Papermaker85 5,000+ posts]

lulz. So he can understand it better. Classic.

Understand what better that you are limiting output by usig a smaller port?

You have yet to determine if the lowend output is a matter of too small a box or port area limiting output at tuning. Or if its actually playing below tuning.

My sub is in a box a tad small and drops 10hz below tuning. If i made tge box bigger it will get lower and louder down low and wont affect topend..

 

[Jeffdachef 5,000+ posts]

8

Understand what better that you are limiting output by usig a smaller port? You have yet to determine if the lowend output is a matter of too small a box or port area limiting output at tuning. Or if its actually playing below tuning.

My sub is in a box a tad small and drops 10hz below tuning. If i made tge box bigger it will get lower and louder down low and wont affect topend..

Well in my case going from 13.5 port per foot to 9.5 port per foot got me louder with a ton more output. Going down to 6 port per foot lost a little output but hits 15 to 35hz way more violently. Lost 55hz and above.

13.5 port per foot lost all output and bandwidth

 

[Boomin_tahoe 5,000+ posts]

Understand what better that you are limiting output by usig a smaller port? You have yet to determine if the lowend output is a matter of too small a box or port area limiting output at tuning. Or if its actually playing below tuning.

My sub is in a box a tad small and drops 10hz below tuning. If i made tge box bigger it will get lower and louder down low and wont affect topend..

Let's see it then mr. all talk.

 

[Papermaker85 5,000+ posts]

8
Well in my case going from 13.5 port per foot to 9.5 port per foot got me louder with a ton more output. Going down to 6 port per foot lost a little output but hits 15 to 35hz way more violently. Lost 55hz and above.

13.5 port per foot lost all output and bandwidth

Same tune? Sound like something is wrong.. More port are means larger peak around tuning. Port area per cub is basically usless.. Port are depends on displacement and tuning frequency. Ie if you had too much port are tunedbeigher it let the subs unload faster under tuning.. Limiting port controls the mass better but from resistance..

With the larger port it unloaded faster.. It a system design error. Could be the subs Rms is low could be tge box is to big could be cancallation..

 

[Hertz Mafia]

Same tune? Sound like something is wrong.. More port are means larger peak around tuning. Port area per cub is basically usless.. Port are depends on displacement and tuning frequency. Ie if you had too much port are tunedbeigher it let the subs unload faster under tuning.. Limiting port controls the mass better but from resistance..With the larger port it unloaded faster.. It a system design error. Could be the subs Rms is low could be tge box is to big could be cancallation..

Cscstang built his box plans. I doubt it's wrong.

 

[Papermaker85 5,000+ posts]

Cscstang built his box plans. I doubt it's wrong.

My point is that is why you can't use cubic foot/port area. There are a few variables that determine how much mechanical/acoustical forces dampen the cone.

i'll link this page for you to refer to for specific terms. https://www.klippel.de/know-how/measurements/measurement-overview.html

1. The suspension based on its stiffness to mass and its actual mechanical resistance. This parameter is known as QMS and Rms.. Rms simply put is how much resistance mechanically the suspension has towards any movement. while QMS its it mechanical damping.Also dont forget the Kms curve which is a measure of the suspensions stiffness over stroke..

2. The Box Size or QTC which is the Total damping of the box. Of course the smaller the box the more damped it will be.. What this means the box has a greater control over the oscillation of the driver. when the driver moves outward its creates a negative pressure(inside the box) IE a vacuum on the other hand outside the box it creates a positive pressure and vice verse when it goes rearward it creates a positive pressure inside the box and a negative pressure outside the box. The greater the pressure difference the higher the SPL just like the greater the potential in charge the higher the voltage. amperage is the current flow where in the displacement would be the same as current flow.. together they equal power/output

so what does that mean? the larger the box the easier the woofer can create those differences in pressure its also means less compliance IE the stiffness of the airmass load on the cone acting to stop the cone. it also mans the sub can excurt easier so its naturally more efficient at lower frequencies!

3. The port as well has acoustical resistance/impedance just like the woofer has mechanical resistance. The lower the port area the more resistance you get between the air going in and out the enclosure to create the sound wave or the negative pressure and positive pressure. The port also has compliance because it has air mass trapped in it as well and that has a "weight" to it. The port actually has a impedance curve acoustically speaking hence the reason for transmission lines)

So the higher amount of port area you have the lower the damping on the cone it also has a less resistance so it not only has more "losses" which changes your QTC.(above and below tuning the box is a leaky sealed box! This is the reason SPL boxes fall off fast above tuning and other alignments as well) and at tuning it also lowers damping and resistance at tuning while having a higher displacement capability becasue the air in the port actually acts like a diaphragm. This causes the sub to peak harder. This is the reason SPL installs use so much port area.

so the QTC has a great affect on the subs mechanical dampening. To high a QTC you will loose a ton of mechanical powerhandling and damping killing transient response and output.

The air mass in the port has an affect on the subs damping as will is the impedance of the port. to much will cause a lower Q and the ports pass-band will be come very limited affecting QTC as well limiting overall dampening and pass-band as well..

The subs actual mechanical resistance and its ability to dampen the mass of the diaphragm and the air mass of the port. also the subs QES which is the driving force and its ability to dampen the mass..

its funny people never wonder why its suggested a stronger motor should be used in ported applications.

 

[Papermaker85 5,000+ posts]

https://www.klippel.de/know-how/measurements/measurement-overview.html

 

[wew lad 5,000+ posts]

The ****... we're talking about in this situation, yes we know that the driver parameters make a big difference but we're offering a solution without changing his setup drastically

Taking **** out of context just to show you know something just negates your input altogether

 

[Papermaker85 5,000+ posts]

The ****... we're talking about in this situation, yes we know that the driver parameters make a big difference but we're offering a solution without changing his setup drastically
Taking **** out of context just to show you know something just negates your input altogether

my point is we can't determine the problem without the information.

 

[Papermaker85 5,000+ posts]

8
Well in my case going from 13.5 port per foot to 9.5 port per foot got me louder with a ton more output. Going down to 6 port per foot lost a little output but hits 15 to 35hz way more violently. Lost 55hz and above.

13.5 port per foot lost all output and bandwidth

if you decide you want to borrow my DATs to test your drivers parameters ill send it to you as long as you return it. im positive the parameters are much different than the site says.