Subwoofer output css sdx

[Stones]

We are missing vital information from your post. That is, what enclosure are those sub drivers in? Your Yamaha has enough voltage from the sub out to drive those amps.

So I have to conclude that either those sub drivers are in the wrong box, or that you have them in a sealed box, but have not provided the requisite 12 db per octave boost below F3, and the high pass filter at xmax to prevent over excursion is they are in the optimal sealed box.

The 12" drivers are capable of an F3 of 24 Hz in a ported box, but 45 Hz in a sealed box without appropriate Eq. I have not modeled those drivers, but that is the info from the spec. sheet. If you just threw those drivers in any old box that is your problem. Sub design is an art that has to be learned. Other speakers are even tougher.

So you have only provided details on the sub driver, and that is not even really half of the sub equation.

I know this is an old post but I missed a key part of your post and I was hoping you could clarify .

you said the specs says f3 of 45hz.
For a sealed enclosure.
I and using a sealed enclosure built to spec so should I have my high pass filter set to 45hz?
If so Should I always set my high pass filter to the f3 ?

We are missing vital information from your post. That is, what enclosure are those sub drivers in? Your Yamaha has enough voltage from the sub out to drive those amps.

So I have to conclude that either those sub drivers are in the wrong box, or that you have them in a sealed box, but have not provided the requisite 12 db per octave boost below F3, and the high pass filter at xmax to prevent over excursion is they are in the optimal sealed box.

The 12" drivers are capable of an F3 of 24 Hz in a ported box, but 45 Hz in a sealed box without appropriate Eq. I have not modeled those drivers, but that is the info from the spec. sheet. If you just threw those drivers in any old box that is your problem. Sub design is an art that has to be learned. Other speakers are even tougher.

So you have only provided details on the sub driver, and that is not even really half of the sub equation.

 

[Stones]

I know this is an old post but I missed a key part of your post and I was hoping you could clarify .

you said the specs says f3 of 45hz.
For a sealed enclosure.
I and using a sealed enclosure built to spec so should I have my high pass filter set to 45hz?
If so Should I always set my high pass filter to the f3 ?

Also I have 3 filter options on my mini dsp peak, low shelf, high shelf . . I have been using peak . Thank you

 

[TLS Guy]

I know this is an old post but I missed a key part of your post and I was hoping you could clarify .

you said the specs says f3 of 45hz.
For a sealed enclosure.
I and using a sealed enclosure built to spec so should I have my high pass filter set to 45hz?
If so Should I always set my high pass filter to the f3 ?

No. You boost the signal at 12 db per octave below 45 Hz, and then you high pass it just before the driver runs out of xmax.

I have just reviewed my model. The problem is that is just an awful sub driver. Actually it is not even fit to be called sub driver.

It is out of xmax by 35 Hz. So it will not even quite take half an octave of boost.

Its T/S parameters are really badly chosen.

The most important advice I can give you, is to select a better driver and start from scratch. That driver is a lost cause.

 

[Stones]

No. You boost the signal at 12 db per octave below 45 Hz, and then you high pass it just before the driver runs out of xmax.

I have just reviewed my model. The problem is that is just an awful sub driver. Actually it is not even fit to be called sub driver.

It is out of xmax by 35 Hz. So it will not even quite take half an octave of boost.

Its T/S parameters are really badly chosen.

The most important advice I can give you, is to select a better driver and start from scratch. That driver is a lost cause.

Thanks again.
I’m not doubting your knowledge , it’s a bummer I bought them based on audiobolics rave review. In there article it claimed the woofer is far superior to anything offered by top brands like svs and it was just a matter of being willing to do the diy work. Unfortunately I lack the funds to start over right now.

thanks again .

 

[TLS Guy]

Thanks again.
I’m not doubting your knowledge , it’s a bummer I bought them based on audiobolics rave review. In there article it claimed the woofer is far superior to anything offered by top brands like svs and it was just a matter of being willing to do the diy work. Unfortunately I lack the funds to start over right now.

thanks again .

Don't forget though that what I said is at full power. You don't have to blast the thing. So if you boost 12 db per octave below 45 Hz and high pass at 25 Hz, then played at reasonable domestic levels it will sound fine, especially for music. It won't break windows for Hollywood effects, but used sensibly it will be fine.

 

[TLS Guy]

Hello. A couple of weeks ago I finished building a sealed CCS SDX 15" sub. The enclousure size is 3.75cf (internal), the amp is ED LT1300 and a ED EQ2 eq.

After running my yamaha YPEO, the sub is caligrated with my radio shack digital meter. The sub is on a space of 4,500-5,000cf room. The sub sounds good on music and at moderate levels, good on movies too. The problem is when the sub hits around 100db or higher on movies such as explosions, it makes a popping sound (driver bottoms out). My sitting position is 9ft from the sub. The receiver LFE setting is at 0 and the output at -10. Crossover is set at 80, small on the speakers and calibrated with the sub at 75db. The volume on the amp is set at 10:00 and the phase is 0. I've run it with and without the ED EQ2 but no luck getting rid of that popping sound. I plugged the receiver and the sub to different outlets (I thought maybe a lack of current from one outlet was a factor), well, no luck. I don't believe the amp is clipping. The enclousure is made out of birch ply, heavily braced (check my forum on "first CCS SDX 15" sub made" here. The space from the back of the driver to the plate amp is about 4". Maybe the sub is not wired correctly? It's a D2oms sub. Thanks for your help.

Last time you were on here we were designing for the 10" and 12" drivers. I see you used the 15" which is a much more promising driver.

However, who told you to make the box volume 3.7 cu.ft? The correct box volume is 1.7 cu.ft plus driver and bracing volume. Air volume needs to be 1.7 cu.ft, that gives a just acceptable Qtc of 0.7. You are having bottoming because the cabinet is not giving the driver enough back pressure. Also the Qtc is way too high.

The good new is that in the correct box you can give 12 db of boost below 40 Hz (F3 is 42 Hz) and high pass at 20 Hz. You have enough xmax to do that. If you follow those instructions you will have two good sealed subs, that will blast you our of 'home and hearth", before they bottom.

 

[TLS Guy]

Last time you were on here we were designing for the 10" and 12" drivers. I see you used the 15" which is a much more promising driver.

However, who told you to make the box volume 3.7 cu.ft? The correct box volume is 1.7 cu.ft plus driver and bracing volume. Air volume needs to be 1.7 cu.ft, that gives a just acceptable Qtc of 0.7. You are having bottoming because the cabinet is not giving the driver enough back pressure. Also the Qtc is way too high.

The good new is that in the correct box you can give 12 db of boost below 40 Hz (F3 is 42 Hz) and high pass at 20 Hz. You have enough xmax to do that. If you follow those instructions you will have two good sealed subs, that will blast you our of 'home and hearth", before they bottom.

Here is a pdf of the model. You can see from the model that you would have to smoke the voice coil before running it out of x-max.

 

[Stones]

I guess for the price is somewhat operative here.

However, from an engineering standpoint a sealed sub is an awful idea.

The reason being is that a loudspeaker cone is an absolutely atrocious coupler to air. That is why you have the pretty much useless response before Eq. The only advantage of a sealed design is domestic harmony, after that it ALL downhill.

Loudspeakers for good bass reproduction need an acoustic transformer. That mean a pipe, horn or Helmholtz resonator. Of which the former two are the most efficient, but the least conducive to domestic harmony.

The ported enclosure is a Helmholtz resonator. In the operative FR the cone of the driver almost stops still and the bass is efficiently produced via the port. Below F3 the driver quickly decouples from the box.

Specialized pipes, known as transmission lines can be designed that give broader, more efficient low Q support, which is my favored approach.

Horns are highly efficient, but complex and large.

You just have to consider musical instruments. Pipe organs, flutes and woodwinds like the oboes and clarinets can fill concert halls from the vibrations of small reeds or passage of air over a ledge. The most powerful instruments like horns, trumpets and trombones can blast you out of your seat just from the vibrations of human lips.

The bottom line is that the closed box loudspeaker, seemingly simple is from an acoustic point of view a very bad idea, and expensive to execute properly. It is highly wasteful of resources. It takes massive expensive motor systems and monstrous amounts of power to execute properly.

In your situation the 12" drivers are doing the majority of the lifting, and I have to say that the 10" drivers are contributing next to nothing to the table. For future reference using different drivers like you have is not a sound acoustic plan.

It was a hard pill to swallow but I finally broke down and took your advice . I sold everything and bought two SVS pb2000 pros and couldn’t be happier. Much simpler set up and way better results .

the CSS did sound good with music but couldn’t get the job done with movies.

Thanks for all your time and advice .

 

[TLS Guy]

It was a hard pill to swallow but I finally broke down and took your advice . I sold everything and bought two SVS pb2000 pros and couldn’t be happier. Much simpler set up and way better results .

the CSS did sound good with music but couldn’t get the job done with movies.

Thanks for all your time and advice .

Good to know you are getting the results you wanted. Thanks for the feedback.