Curious about passive subwoofers – who’s using them and how?

[troye]

Hey everyone,

I’ve been seeing that while most people go with active subs these days, there are still quite a few who stick with passive subwoofers. I’m really curious to learn from those of you who use them.

A few things I’d love to hear about:

• Why passive? What made you choose a passive sub over an active one? (flexibility with amps/DSP, reliability, DIY, cost, etc.)
• Your setup – Which passive subwoofer(s) are you running, and what amp do you pair them with?
• Use cases – Do you mainly use it for home theater, music, gaming, or a mix?
• Amps – For using dedicated subwoofer amps, which features do you find essential (power output, filters, phase, DSP, auto on/off, trigger, etc.) and which ones are just nice-to-have?
• Good and bad – what’s been great (or frustrating) about today’s subwoofer amps?

I’m not looking for measurements or lab-style analysis (though always welcome on ASR!), but more your personal experiences and what you’ve learned from using passive subs in the real world.

Looking forward to hearing your setups and lessons learned — I feel like this is an area where shared experiences can really help others considering the same path.

 

[ppataki]

Hey everyone,

I’ve been seeing that while most people go with active subs these days, there are still quite a few who stick with passive subwoofers. I’m really curious to learn from those of you who use them.

A few things I’d love to hear about:

• Why passive? What made you choose a passive sub over an active one? (flexibility with amps/DSP, reliability, DIY, cost, etc.)
• Your setup – Which passive subwoofer(s) are you running, and what amp do you pair them with?
• Use cases – Do you mainly use it for home theater, music, gaming, or a mix?
• Amps – For using dedicated subwoofer amps, which features do you find essential (power output, filters, phase, DSP, auto on/off, trigger, etc.) and which ones are just nice-to-have?
• Good and bad – what’s been great (or frustrating) about today’s subwoofer amps?

I’m not looking for measurements or lab-style analysis (though always welcome on ASR!), but more your personal experiences and what you’ve learned from using passive subs in the real world.

Looking forward to hearing your setups and lessons learned — I feel like this is an area where shared experiences can really help others considering the same path.

I only use DIY passive subwoofers

1. This is my front sub in my living room:

P

'Lavoce SSF153.00 15" based dual opposed subwoofer project'

Jan 8, 2024

I am excited to share my next project here!
After converting my MCLAs to a sub I have decided to look for a more traditional approach to subs - hence the below project came to my mind
I have designed and built several dual opposed subwoofers (DOS) already - I can say I really love this design

This time I am going to use two Lavoce SSF153.00 (4 ohm version) 15" drivers - they shall arrive early next week
I will put them in a sealed cabinet using 18mm MDF with a size of 630 x 450 x 400 mm

I will use a Sabaj A30A full digital amp to drive them with an approx...

• ppataki
• Replies: 39
• Forum: DIY Audio Forum

• 

2. This is my rear sub in the (same) living room:

P

'Using four bass guitar drivers to build a dual opposed subwoofer project'

Aug 22, 2024

Even the title is unorthodox
I have recently built a dual opposed subwoofer (DOS) for my home office which was a hugely successful project for me. Once it was done I have taken it downstairs in my living room and started playing around with what I can do with two subs instead of just one...
The result was mind-blowing. I could bring my (room gain induced) -3dB point from 22Hz to 18Hz (or literally to 5Hz but I set Dirac to cut it at 18Hz to be more realistic, see below)

Step response got better too:

(note: I have not used Dirac Live Bass Control...

• ppataki
• Replies: 39
• Forum: DIY Audio Forum

• 

3. And this is the sub in my home office:

P

'Another 8" dual opposed subwoofer project'

Jun 11, 2024

After finishing my new DIY system in my home office/bedroom I have decided to also add (build) a subwoofer to it

I have really huge dips in the frequency response due to room modes; see the before/after DSP correction curve below:

When running REW simulations for adding a sub to the system, the resulting curve looks a bit better (highlighted):

So driven by curiosity I have decided to add a 8" dual opposed subwoofer (DOS) to the system

I will be using two Lavoce SSF082.00L 8-ohm drivers for the project (wired in parallel to get 4-ohm)...

• ppataki
• Replies: 20
• Forum: DIY Audio Forum

• 

Reasons for using DIY passive subs: extreme price/value ratio (like literally lightyears above commercially available products), flexibility with amp and DSP setup and as a result of that: better integration

Amps used: 3eAudio A7 Mono, Fosi V3 Mono

DSP: PC-based using Jriver and various VST plugins (to set up the crossover, delay, volume, low shelf filters, peaking filters, all-pass filters)

Bad: you need to know what you are doing

 

[Wayne A. Pflughaupt]

I expect most passive sub users have home-made DIY subs rather than something off the shelf, as factory passive subs are pretty scarce. Often the motivation is the desire to get more performance than manufactured subs typically have. I recently saw someone at AVS mention his system with four 18” subs.

Others with good woodworking skills just like the satisfaction of making their own stuff.

I had a DIY passive sub for 10 years or so. At the time I was living in an upscale house and didn’t want a big black box on the floor spoiling the aesthetics. I converted a built-in cabinet into a subwoofer. Here’s a thread detailing the build:

https://www.hometheatershack.com/threads/built-in-subwoofer-project.15599/?post_id=138001#post-138001

Regards,
Wayne A. Pflughaupt

 

[DanielT]

Hey everyone,

I’ve been seeing that while most people go with active subs these days, there are still quite a few who stick with passive subwoofers. I’m really curious to learn from those of you who use them.

A few things I’d love to hear about:

• Why passive? What made you choose a passive sub over an active one? (flexibility with amps/DSP, reliability, DIY, cost, etc.)
• Your setup – Which passive subwoofer(s) are you running, and what amp do you pair them with?
• Use cases – Do you mainly use it for home theater, music, gaming, or a mix?
• Amps – For using dedicated subwoofer amps, which features do you find essential (power output, filters, phase, DSP, auto on/off, trigger, etc.) and which ones are just nice-to-have?
• Good and bad – what’s been great (or frustrating) about today’s subwoofer amps?

I’m not looking for measurements or lab-style analysis (though always welcome on ASR!), but more your personal experiences and what you’ve learned from using passive subs in the real world.

Looking forward to hearing your setups and lessons learned — I feel like this is an area where shared experiences can really help others considering the same path.

Hello and welcome to ASR.

My guess, which ppataki above is an example of, is that DIY subwoofers are passive. It is kind of in the nature so to say. Then the DIY subwoofer is added with subwoofer amplifier plus the filters and DSP/EQ that are desired. Which in practice then makes them active.
Where you physically place the subwoofer amp does not matter for the concept of active speaker, that is.
An active subwoofer does not have to have a subwoofer plate amplifier (with LP-filter and possibly DSP/EQ) mounted on the subwoofer for it to be considered active.

The DIY advantage of two bass boxes in stereo is that the crossover can be set higher than with commercial active subwoofers that usually have a cut off of 120 Hz (thereabouts). With two bass boxes, which can work down in the subrange area up to around let's say 300Hz-400 Hz, plus two-way speakers on top it is actually a three-way speaker. With, if you want, active bass boxes.

Good integration bass boxes with top speakers/midrange and tweeter are of course needed but I leave the practical aspects aside.
Same thing with subwoofer plus speakers. It can require a lot of work to integrate, to blend together in a good way.

 

[DanielT]

I expect most passive sub users have home-made DIY subs rather than something off the shelf, as fac-tory passive subs are pretty scarce. Often the motivation is the desire to get more performance than manufactured subs typically have. I recently saw someone at AVS mention his system with four 18” subs.

Others with good woodworking skills just like the satisfaction of making their own stuff.

I had a DIY passive sub for 10 years or so. At the time I was living in an upscale house and didn’t want a big black box on the floor spoiling the aesthetics. I converted a built-in cabinet into a subwoofer. Here’s a thread detailing the build:

https://www.hometheatershack.com/threads/built-in-subwoofer-project.15599/?post_id=138001#post-138001

Regards,
Wayne A. Pflughaupt

I expect most passive sub users have home-made DIY subs...

You're ahead of me, I see.

 

[MCH]

I use two "passivated" subs:
Why? It was not intentional, they were svs SB1000 that I bought because of its size, but both came with a constant rumble I could not fix. The only solution that worked was to bypass the internal amp+dsp and use a external amp. The external amps are aiyima a07 max. I run everything from a rpi with a motu ultra lite mk5 doing DAC tasks.
I am generally happy but at the moment I can't listen very loud. But this is about to change (we are moving) and I am very curious to know if my current setup will be enough in a much larger space and no neighbors....

 

[Cogito]

In my case, my passive sub was designed to work with matching bookshelf speaker with a fixed high-pass filter. The Phase Technologies PC-80/90 sub sat system. Great sounding system.

 

[Waxx]

I have bass cabinets that goes into subwoofer territory, but are filter up high at 300Hz to go to a top, they are Scanspeak 26W8534G00 in 77L sealed diy cabinets amped with Ncore amps and MinidSP as crossover. They are not tha powerfull, but way more powerfull than i need in my small listening room with neighbours. They are flat wihout eq to about 32Hz (anchionic), but as i use them in room i did do (manual) room correction on them and tuned them slightly lower, but also with a highpass (8th order at 25Hz).

I'm planning to make some ripole subs (but have been ill for a while) for in my office to use with bookshelf speakers that go easely into their low 40's (so i have headroom to filter), and build tons of subs and bassboxes for others also, going from 21" monster subs to tiny 6" desktop subs, active and passive. But for hifi in an average european livingroom a pair of 10 or 12"s is often the right size for subs, at least in my experience.

 

[DanielT]

I use two "passivated" subs:
Why? It was not intentional, they were svs SB1000 that I bought because of its size, but both came with a constant rumble I could not fix. The only solution that worked was to bypass the internal amp+dsp and use a external amp. The external amps are aiyima a07 max. I run everything from a rpi with a motu ultra lite mk5 doing DAC tasks.
I am generally happy but at the moment I can't listen very loud. But this is about to change (we are moving) and I am very curious to know if my current setup will be enough in a much larger space and no neighbors....

Depends on how loud you want to play. A compact sealed subwoofer cabinet literally eats amp power.The Sledge STA-300D that was in your subwoofer had 300 watts RMS, 700+ watts peak power just for reference.

SVS SB-1000 Subwoofer | 12-inch Driver | 300 Watts RMS

Small enough to conceal yet delivers massive subwoofer output and low frequency extension for home theater and music.

www.svsound.com

My SVS SB12-NSD subwoofer had a similar compact sealed cabinet with a Sledge amp of: 400 Watts (RMS), and 800 Watts.
The clipping indicator started flashing already at a little higher than normal listening volume. It just loved to eat amp watts.
That said, in a smaller room at normal listening volume with not too demanding music a really nice subwoofer.

The SVS SB12-NSD with its 12 inch subwoofer driver didn't stand a chance against my vintage Yamaha YST -SW300 subwoofer with its 12 sub driver. That despite the fact that the Yamaha subwoofer "only" has an amp of 175 watts BUT it is a ported sub (higher efficiency than seald) in a larger box.
I'll take a well-designed ported subwoofer any day of the week vs a sealed one. The problem is that many ported subwoofers are poorly designed with port noise and so on. It can be really annoying.

Hofmann's Iron Law​

Hofmann theorized that when woofers are mounted in speaker enclosures, the designer would have to accept that there are three trade-offs. Hofmann argued that the designer had "...three parameters that cannot all be had at the same time. They are low-bass reproduction, small (enclosure) size, and high (output) sensitivity." Hofmann stated that designers could pick two of these three parameters, but in doing so, it would compromise the third parameter.

For example, a designer who wants good, deep low-frequency sound and high sensitivity can obtain these goals, but they will have to use a large speaker enclosure. Similarly, if a designer is forced by space constraints to use a very small cabinet, and they aim to get good, deep low-frequency sound, the sensitivity will be compromised (i.e., a small cabinet with deep bass would need a very powerful amplifier).

Josef Anton Hofmann - Wikipedia

en.wikipedia.org

 

[HoweSound]

Hello and welcome to ASR.

My guess, which ppataki above is an example of, is that DIY subwoofers are passive. It is kind of in the nature so to say. Then the DIY subwoofer is added with subwoofer amplifier plus the filters and DSP/EQ that are desired. Which in practice then makes them active.
Where you physically place the subwoofer amp does not matter for the concept of active speaker, that is.
An active subwoofer does not have to have a subwoofer plate amplifier (with LP-filter and possibly DSP/EQ) mounted on the subwoofer for it to be considered active.

I had a truly passive DIY sub back in the 80's/90's. It was a kit from a company called Speakerlab, iirc and consisted of two 10" woofers and a passive crossover built into a large sealed enclosure. The speaker output from my Kenwood integrated amplifier went to the passive sub, then to my book shelf speakers- essentially four way passive speakers in separate boxes. The sound quality and bass output was pretty dismal. Eventually I built a new cabinet with a 250 watt subwoofer plate amp feeding the two 10" woofers, now in a down firing cabinet fed from pre-out, or sub out from the amp - a DIY active sub, which now sounded pretty good. Even if I had used a remote amp and x-over to power the sub, it would still be active. I suspect I am one of the few who were tempted to actually make a passive sub.

 

[DanielT]

It gets a little confusing if you don't define what an active subwoofer is and for that matter what an active speaker is.

Like this. Two speakers, one with a built-in amplifier, both speakers have passive crossovers. Speaker cable must be run from one speaker to the other. Are they active speakers?
(In my world yes, I follow the simple principle, that if no amp needs to be added then the sub/speakers are active)

Do both speakers have to have built-in amplifiers to be considered active? Or do you need separate amplifiers for each speaker driver? Is DSP now a requirement to be considered an active sub/speaker? No passive crossover in order to... and so on.

 

[DVDdoug]

while most people go with active subs these days,

AVRs don't have a speaker-output for the subwoofer.

I built two 15-inch subs in large ported cabinets. They are passive because I had an "extra" amplifier. If I didn't have the amplifier I would have made them active. No DSP or room correction (my AVR doesn't have it). Just bass management from my AVR. And I have a Sub Bass Synthesizer.

 

[Devnull]

AVRs don't have a speaker-output for the subwoofer.

I built two 15-inch subs in large ported cabinets. They are passive because I had an "extra" amplifier. If I didn't have the amplifier I would have made them active. No DSP or room correction (my AVR doesn't have it). Just bass management from my AVR. And I have a Sub Bass Synthesizer.

Some AVRs do or at least did have speaker level outputs for passive subwoofers. Onkyo/Integra had them and I believe Denon had them. It's been a while since I specifically looked for that feature.

 

[anotherhobby]

I run 4 passive 8" Dayton Ultimax subs for my office stereo paired with some Revel M105s. I went with passive subs strictly because of DIY, where I needed very compact subs of unique shapes to fit into my small 10'x10' space. This is what I ended up building:

They are powered by a pair of Crown XL1500 amps, with each sub getting it's own ~500w channel. The amps were bought used off ebay for $250 each, so amplification was only $125 per sub. DSP is handled by a miniDSP Flex with Dirac Live, with 2 outputs going to a t.racks DSP 4x4 Mini, which feeds the 4 subs. The subs are paired up as front/rear L and front/rear R, with the t.racks only being used to set delay between front and rear.

Post calibration measurements for both channels are pretty good for a 10x10' room. Since they are only 8" subs, this curve holds to about 100 dB and then starts compressing, which is more than enough for nearfield in my office.

 

[troye]

I only use DIY passive subwoofers

1. This is my front sub in my living room:

P

'Lavoce SSF153.00 15" based dual opposed subwoofer project'

Jan 8, 2024

I am excited to share my next project here!
After converting my MCLAs to a sub I have decided to look for a more traditional approach to subs - hence the below project came to my mind
I have designed and built several dual opposed subwoofers (DOS) already - I can say I really love this design

This time I am going to use two Lavoce SSF153.00 (4 ohm version) 15" drivers - they shall arrive early next week
I will put them in a sealed cabinet using 18mm MDF with a size of 630 x 450 x 400 mm

I will use a Sabaj A30A full digital amp to drive them with an approx...

• ppataki
• Replies: 39
• Forum: DIY Audio Forum

• 

2. This is my rear sub in the (same) living room:

P

'Using four bass guitar drivers to build a dual opposed subwoofer project'

Aug 22, 2024

Even the title is unorthodox
I have recently built a dual opposed subwoofer (DOS) for my home office which was a hugely successful project for me. Once it was done I have taken it downstairs in my living room and started playing around with what I can do with two subs instead of just one...
The result was mind-blowing. I could bring my (room gain induced) -3dB point from 22Hz to 18Hz (or literally to 5Hz but I set Dirac to cut it at 18Hz to be more realistic, see below)

Step response got better too:

(note: I have not used Dirac Live Bass Control...

• ppataki
• Replies: 39
• Forum: DIY Audio Forum

• 

3. And this is the sub in my home office:

P

'Another 8" dual opposed subwoofer project'

Jun 11, 2024

After finishing my new DIY system in my home office/bedroom I have decided to also add (build) a subwoofer to it

I have really huge dips in the frequency response due to room modes; see the before/after DSP correction curve below:

When running REW simulations for adding a sub to the system, the resulting curve looks a bit better (highlighted):

So driven by curiosity I have decided to add a 8" dual opposed subwoofer (DOS) to the system

I will be using two Lavoce SSF082.00L 8-ohm drivers for the project (wired in parallel to get 4-ohm)...

• ppataki
• Replies: 20
• Forum: DIY Audio Forum

• 

Reasons for using DIY passive subs: extreme price/value ratio (like literally lightyears above commercially available products), flexibility with amp and DSP setup and as a result of that: better integration

Amps used: 3eAudio A7 Mono, Fosi V3 Mono

DSP: PC-based using Jriver and various VST plugins (to set up the crossover, delay, volume, low shelf filters, peaking filters, all-pass filters)

Bad: you need to know what you are doing

wow, it`s truly impressive and incredible

 

[troye]

Hello and welcome to ASR.

My guess, which ppataki above is an example of, is that DIY subwoofers are passive. It is kind of in the nature so to say. Then the DIY subwoofer is added with subwoofer amplifier plus the filters and DSP/EQ that are desired. Which in practice then makes them active.
Where you physically place the subwoofer amp does not matter for the concept of active speaker, that is.
An active subwoofer does not have to have a subwoofer plate amplifier (with LP-filter and possibly DSP/EQ) mounted on the subwoofer for it to be considered active.

The DIY advantage of two bass boxes in stereo is that the crossover can be set higher than with commercial active subwoofers that usually have a cut off of 120 Hz (thereabouts). With two bass boxes, which can work down in the subrange area up to around let's say 300Hz-400 Hz, plus two-way speakers on top it is actually a three-way speaker. With, if you want, active bass boxes.

Good integration bass boxes with top speakers/midrange and tweeter are of course needed but I leave the practical aspects aside.
Same thing with subwoofer plus speakers. It can require a lot of work to integrate, to blend together in a good way.

Thanks dude, but why do people choose DIY passive subwoofer instead of buying a passive sub or an active one?

 

[concorde1]

Thanks dude, but why do people choose DIY passive subwoofer instead of buying a passive sub or an active one?

Reasons for using DIY passive subs: extreme price/value ratio (like literally lightyears above commercially available products), flexibility with amp and DSP setup and as a result of that: better integration

As for me:

• Why passive? I like having speakers/subs separate from amps so they can be repaired separately if need be - and I built one of my power amps which took heaps of effort and I have no intention to turn my back on that
• Your setup – Almost finished my DIY 2x Scan-Speak Revelator 32W 12" subs - will be powered by my Topping PA7 plus power amp
• Use cases – Music movies gaming - everything
• Amps – Essential features - enough power -- I prefer separate DSP DAC (in my case desktop PC (Equalizer APO) -> Topping DM7 multichannel DAC)
• Good and bad – I prefer to use a normal power amp and DSP separately - because most "subwoofer amps" seem overpriced

 

[DanielT]

Thanks dude, but why do people choose DIY passive subwoofer instead of buying a passive sub or an active one?

In addition to what has already been mentioned, see @anotherhobby subwoofers in #14. Custom-made. You can only get that via DIY. Or if you commission a carpentry company to make them.

DIY subwoofer for those who do it is a fun hobby. Otherwise they wouldn't have done them of course. Plus, homemade food tastes best.

 

[Wayne A. Pflughaupt]

Thanks dude, but why do people choose DIY passive subwoofer instead of buying a passive sub or an active one?

Someone will correct me if I’m wrong, but AFAIK off-the-shelf passive subs are few and far between. I’ve heard of a few “architectural” models, but practically nothing beyond that.

Regards,
Wayne A. Pflughaupt

 

[AnalogSteph]

Any kinds of subwoofer arrays (e.g. SBA, DBA) tend to be using passive drivers with traditional power amps. The classic active sub is handy when all you need is one or two tops, but if you need a whole bunch in a custom installation the passive route tends to be more practical.