Must a sealed subwoofer have DSP?

[Zeppelin]

Learning about the Subwoofer world, I have read that DSP is specially desired on sealed subwoofers.

As I am doubting about which second-hand subwoofer I am going to buy this question it's fundamental.

What do you think?

 

[FrankF]

It depends on what you're using it for. If it's home theater most processors and receivers have dsp built in so not really needed. In a stereo set-up without built in dsp it would be a plus. I use 2 JL Audio Fathoms in my home theater and only use Audyssey.

 

[Zeppelin]

It would be used in a 2.1 only music setup.

Does the fact that is a sealed subwoofer, instead of a bass-reflex one, makes it more suitable for a DSP? Or is this sealed vs ported subwoofer DSP situation something created by me?

 

[Chrispy]

Many sealed subs will need a boost in the lower frequencies to offer a flatter response than the typical low end rolloff of a sealed sub. Some sealed subs have it baked into the amp already. Having dsp to deal with integration of a sub and for room modes can be helpful in either design. Some ported subs need a protective high pass filter below tuning point to prevent damage.

 

[Hapo]

 

[alex-z]

No, sealed subs do not require DSP. If carefully designed and positioned, you can roughly match the room gain boost to the rolloff rate of a sealed sub, and get an in-room response with great bass extension. Sealed subs usually ship with DSP because most consumers don't know what room gain is, much less how to select a subwoofer to match it. It is always preferable to have customers think there is a bit too much bass extension, rather than too little.

 

[ZolaIII]

You do need to EQ the bass region (room influence to it) more than anything else sub closed/ported or without it. Closed sub's will interact with room less than ported one's and arguably should have a better impulse response or time domain if you like, meaning less echo. On the other hand port will enable ported one's to go lower but on higher SPL levels you could hear the port, in order to extend it's lowest end and level it up closed sub's will incorporate Linkwitz transform function towards excursion rates of driver's used and amplifier power (done by manufacturer for active one's of course).

 

[Zeppelin]

It depends on what you're using it for. If it's home theater most processors and receivers have dsp built in so not really needed. In a stereo set-up without built in dsp it would be a plus. I use 2 JL Audio Fathoms in my home theater and only use Audyssey.

There is no DPS neither on the amp nor Subwoofer.

No, sealed subs do not require DSP. If carefully designed and positioned, you can roughly match the room gain boost to the rolloff rate of a sealed sub, and get an in-room response with great bass extension. Sealed subs usually ship with DSP because most consumers don't know what room gain is, much less how to select a subwoofer to match it. It is always preferable to have customers think there is a bit too much bass extension, rather than too little.

In my room there is only three spots where it could go, so I hope one of them would be a good one. Do you think a smaller subwoofer, whether sealed or ported, would be easy to set up?

 

[Zeppelin]

You do need to EQ the bass region (room influence to it) more than anything else sub closed/ported or without it. Closed sub's will interact with room less than ported one's and arguably should have a better impulse response or time domain if you like, meaning less echo. On the other hand port will enable ported one's to go lower but on higher SPL levels you could hear the port, in order to extend it's lowest end and level it up closed sub's will incorporate Linkwitz transform function towards excursion rates of driver's used and amplifier power (done by manufacturer for active one's of course).

The subwoofers I am doubting on don't have DSP nor Linkwitz (AFAIK). They are active, and can ensure they don't have DSP. If DSP is required for Linkwitz, they don't have it neither.

When you say to "EQ the bass region", do you mean adjusting the crossover and the position of the sub?

Also want to mention I think if I find a subwoofer with DSP in the money range I am searching at it would probably not be a high quality one, so maybe it makes it worst.

 

[ZolaIII]

@Zeppelin I mean range up to 500 Hz and with PEQ, not crossover parametric filters.
What is jour price range and what exactly do you want to accomplish?

Active Filters

It's usually relatively cheap (simple) circuit board embedded in sub enclosure along with amplifier. It can be done and with digital signal processor of course.

 

[alex-z]

In my room there is only three spots where it could go, so I hope one of them would be a good one. Do you think a smaller subwoofer, whether sealed or ported, would be easy to set up?

With a single subwoofer, there will always be some compromise. Room modes will cause an uneven frequency response, which if you correct them with DSP aka EQ, will worsen the response in another listening position. Having multiple subwoofers is by far the most cost and space efficient way to remedy that.

Sealed or ported subs do not significantly vary in their difficulty of room integration. As a over-generalized rule, I would select sealed for small rooms simply because of the extra room gain that will be present, but there is no reason why a ported sub could not sound good.

 

[ZolaIII]

@alex-z a single simple PEQ (to shave sub) and only one sub no crossover or anything else:

With a bit of luck of course.

 

[alex-z]

@alex-z a single simple PEQ (to shave sub) and only one sub no crossover or anything else:

With a bit of luck of course.

That is a 220dB scale...

It quite clearly has 10-15dB of variation in the bass response.

 

[ZolaIII]

That is a 220dB scale...

It quite clearly has 10-15dB of variation in the bass response.

One with PEQ is blue line and more like 6~7 dB to 70 dB line, anyway not a problem to level up even more by simply lowering the sub volume a bit. It whose with SVS SB 1000 Pro (which does have DSP) and done on Flex but all of that is less important.
Edit: Interesting part is that guy for who I did it both another one and did partial acoustic treatment and I did him a proper one with a crossover @ 50 Hz for his Focal Diablos and he reverted back to one and that setting. Can even give you a link to listen to it yourself.

 

[Zeppelin]

@Zeppelin I mean range up to 500 Hz and with PEQ, not crossover parametric filters.
What is jour price range and what exactly do you want to accomplish?

Active Filters

It's usually relatively cheap (simple) circuit board embedded in sub enclosure along with amplifier. It can be done and with digital signal processor of course

A PEQ is not in my setup. I tried to find an option to implement something in that way but at the end I didn't happen. Would be a Loki MIni+ a PEQ? I guess you are talking about something that has a more subdivided frequency adjustment.

But what surprises me is you are talking about freq above 500hz, which is a matter of the speaker, not of subwoofer, and I don't understand why adjusting the low frequencies on speakers will benefit the subwoofer. Can you explain me that?

 

[Zeppelin]

Sealed or ported subs do not significantly vary in their difficulty of room integration. As a over-generalized rule, I would select sealed for small rooms simply because of the extra room gain that will be present, but there is no reason why a ported sub could not sound good.

In my "understanding" of the subwoofer positioning situation it seems to me the ported would be more dependent of corners, table/shelf on top, distance to the wall and may be some others variables. Am I wrong thinking the sealed would not have to struggle with those variables?

 

[fpitas]

In my "understanding" of the subwoofer positioning situation it seems to me the ported would be more dependent of corners, table/shelf on top, distance to the wall and may be some others variables. Am I wrong thinking the sealed would not have to struggle with those variables?

As long as you don't block the port badly, you have about the same considerations as sealed.

You can get along without PEQ with any sub, depending on how picky you are about your bass.

 

[ZolaIII]

A PEQ is not in my setup. I tried to find an option to implement something in that way but at the end I didn't happen. Would be a Loki MIni+ a PEQ? I guess you are talking about something that has the frequency more divided.

But what surprises me is you are talking about freq above 500hz, which is a matter of the speaker, not of subwoofer, and I don't understand why adjusting the low frequencies on speakers will benefit the subwoofer. Can you explain me that?

Whose in generally up to 500 Hz on both speakers and sub's.
Let's revert this to the bigining.
What frequency response are you receiving as it is in the first place (measured with calibrated measurement microphone like UMIK-1)?
How is your hearing state (audiologist hearing test)?
What do you hope to achieve in conjunction to above?
For what amount of money on disposal if it's achievable at all in consideration of above?

 

[Zeppelin]

@alex-z a single simple PEQ (to shave sub) and only one sub no crossover or anything else:
View attachment 271486
With a bit of luck of course.

This graph helps to clarify.

Until now, it seems DSP it is not mandatory, but kind of improve bass signal. Also seems DSP is "only" an automatic PEQ.

Do you know a cheap PEQ that can be connected to my setup? The SNR of my Aiyima 08 Pro is 110db, for if it guides you to a non low SNR device.

 

[Chrispy]

You might like this article on schroeder frequency effects https://www.soundandvision.com/content/schroeder-frequency-show-and-tell-part-1 to help explain bass in typical rooms