Subwoofer Upgrade - dual, or better single?

JustinT350

Active Member
Evening all, I'm hoping for a bit of advice.

As with most home set ups, I seem to have found myself slowly upgrading bits as and when I can afford it. Screen, speakers, amp etc. I'm now at the point where I think I need to upgrade my subwoofer. My current set up is -

Denon X3700H AVR
Dali oberon 5s
Dali Zensor surrounds
Dali Alteco atmos
Cambridge Audio Sx120 Subwoofer. Link below


I've done a lot of reading, probably too much. And seem to have got myself confused. My subwoofer to me seems fairly adequate but I guess I don't know what I'm missing. It was bought as a cheap starter sub.

Would adding another Sx120 be worthwhile? Or should I look to change it to something like an SVS pb-1000 or even 2000? (PB seems better for films?)

Will I notice much of a change in a subwoofer swap? Daft question maybe, but at £700 it is a big outlay.

My room is 7.5m x 4.5x

Thanks for any help
 

rccarguy2

Well-known Member
Depends,.for stereo a second one you have will be fine, but for movies I'd rather have one high end one than dual lower end one.

That is fair sized room, yours is roughly same length but yours is wider...but my ceiling is 2.7m high

I'd say get pb2000 or monolith + or monoprice 12" or 15" ported.

I do prefer sealed box myself, a single svs sbu13 copes pretty well in my similar sized room. I think that is a better getting than two of the 12" sealed boxes (I had one)
 

Jester1066

Well-known Member
Evening all, I'm hoping for a bit of advice.

As with most home set ups, I seem to have found myself slowly upgrading bits as and when I can afford it. Screen, speakers, amp etc. I'm now at the point where I think I need to upgrade my subwoofer. My current set up is -

Denon X3700H AVR
Dali oberon 5s
Dali Zensor surrounds
Dali Alteco atmos
Cambridge Audio Sx120 Subwoofer. Link below


I've done a lot of reading, probably too much. And seem to have got myself confused. My subwoofer to me seems fairly adequate but I guess I don't know what I'm missing. It was bought as a cheap starter sub.

Would adding another Sx120 be worthwhile? Or should I look to change it to something like an SVS pb-1000 or even 2000? (PB seems better for films?)

Will I notice much of a change in a subwoofer swap? Daft question maybe, but at £700 it is a big outlay.

My room is 7.5m x 4.5x

Thanks for any help
Yes, you would notice a massive difference (for the better) by upgrading and replacing your current sub with either of the models you mentioned. But there are cheaper alternatives that will also offer a sizeable performance increase.

Ported subs are considered better for films - as they'll generally go lower in terms of frequency than their sealed equivalent. But to achieve this they are physically much bigger in size too.

In my own setup (50/50 movies to music), I've gone for 2x SVS SB2000 Pro's (sealed are better for music, but go plenty deep enough for movies too - My room is 4.57m x 3m). They are £899 RRP each mind.....

Now onto the cheaper alternatives 😂

Is you system use mainly movies? If so, prior to my current subs, I had a BK12-300SB-PR. This is a sealed sub with a bottom mounted passive radiator (the "PR" bit), so it's a little bit like a hybrid sub. It's not big 40cm square, but can dig as deep as some ported subs - due to the passive radiator. Best bit is it costs from £499.95! (Depending on finish).

Here's a review:



They come in a variety of real wood vaneer finishes and are British made. The only reason I sold mine was I couldn't quite fit 2, when wanting to go dual. The SVS are marginally smaller and therefore gained approval from the OH.

The slightly cheaper P12-300SB is the same sub, without the passive radiator. Available in forward or down firing configuration:


2x BK Double Gems would work well in you room also: (from £769.90+shipping - for 2 - depending on finish)


Small sub, big performance. Notice this on the BK site:

"Why Choose the Double Gem
The Double Gem was conceived due to demand for a subwoofer that can fit in limited floor space, we have been told many times by customers that they would love the performance of the larger subwoofers in our range but only had a gap to fit either the Gemini or the XLS200. Whilst listening to subwoofer's in our test room prior to dispatch we are constantly reminded how good two of the Gemini subwoofer's sound. With this in mind it made sense to offer a Double Gemini in as slim a package as possible....the Double Gem was born"

If you order 2 subs (at the same time), they'll even colour match the vaneer!

Give Tom at BK a call. He's good at advising what subs are best in your situation.

Your room is quite big, so maybe get a better single sub to replace your current one. Then get a 2nd identical sub later, when funds allow.

P.S I can also recommend mounting the Alteco's near the ceiling as heights (if you haven't already), will offer a further improvement in sound. I have the same speakers mounted this way myself. 🙂
 
Last edited:

Mr Wolf

Active Member
Will I notice much of a change in a subwoofer swap? Daft question maybe, but at £700 it is a big outlay.

My room is 7.5m x 4.5m
You currently have a sub that is only rated down to 34Hz so you're therefore nearly missing out on the whole first octave of human hearing which starts around 20Hz. Given it only has a 70W amp, its SPL output will also be very limited and is likely to be distorting at higher listening levels.

The difference you'll notice with a new sub will obviously depend on what you buy but if you choose well it should be a night and day difference and I expect you'll have no regrets whatsoever.

As you have quite a large space (circa. 3,000 Ft3 depending on ceiling height) and mention movies as a priority then a ported sub's extra efficiency in the lowest frequencies would be useful where it should have at least twice the output of a comparable sealed sub.

Having recently upgraded to dual (ported) subs in my 2,600Ft3 HT room, I would say the greatest benefit from dual subs is the smoothness of response and the lack of any localisation whatsoever. I will certainly never to go back to a single sub. So, unless you don't physically didn't have the space to position them optimally, I would suggest that whatever you decide to buy you should leave the option open to buy a matching second sub down the track.
 

rccarguy2

Well-known Member
Sealed actually go lower as they don't have the sharp drop off ported subs have at and under port tune. Thd and port chuffing on ported subs at frequency below tune increased that's why ported sub should have sub sonic filter. No sure if most potted subs have this feature buy the svs ones I did have.

Passive radiator doesn't make it go lower, it lowers distortion.

In a medium sized room I think double gems would be good, also pretty small and look cool with dual driver.

Bk have excellent pricing, just wish they sort out humming and buzzing they seem to be plagued with it. I've gone past their range for main system so they don't offer anything...unless go for quad double gem or quad xls400 or quad monolith plus or something like that.

Also like if they released higher end models maybe double xls400/ double xls400 pr/2 and double monolith plus /2
 

JustinT350

Active Member
Gents, thanks for all the excellent replies.

A lot to take in and read through, but it looks pretty clear a sub upgrade would be worth while :D

The room is 95% Films. Usually Bluray or Netflix on Sky. Hardly any music played at all. My Altecos are currently upfiring but I am planning on wall mounting them.

I've got the space for dual subs, maybe just not the budget, but quite like the idea of adding a second at a later date.

I've currently got my sub down beside my couch at the back. And would have the second one on the other side. It sites next to the speaker beside the wine fridge

PSX_20201027_093655.jpg
 

Mr Wolf

Active Member
Sealed actually go lower as they don't have the sharp drop off ported subs have at and under port tune.
A sealed sub might play lower than a ported sub but not due to it being sealed. Ported subs have a steeper roll-off for sure because they get to point below the tuning frequency where the contribution from the port(s) falls away but the driver never stops kicking.

Here's an example of the output of two comparable subs with identical amps and drivers - one ported, one sealed.

1620115944589.png


The sealed sub bottoms out at 20Hz where the ported sub has 13.2dB more output which is exactly 2.5x louder.

Plugging the ports of my PB-3000s doesn't cause them to play lower, it just reduces the slope of the roll-off and reduces the overall SPL output.
 

Mr Wolf

Active Member
Gents, thanks for all the excellent replies.

A lot to take in and read through, but it looks pretty clear a sub upgrade would be worth while :D

The room is 95% Films. Usually Bluray or Netflix on Sky. Hardly any music played at all. My Altecos are currently upfiring but I am planning on wall mounting them.

I've got the space for dual subs, maybe just not the budget, but quite like the idea of adding a second at a later date.

I've currently got my sub down beside my couch at the back. And would have the second one on the other side. It sites next to the speaker beside the wine fridge

View attachment 1505594
Looks like you have rectangular room so, if you haven't done it already, I suggest you should model your room with REW's RoomSIM tool as it will estimate the frequency response at your listening position depending where you place the subs.

Through measurement, I've found its predictions to be spookily accurate.
 

Conrad

Moderator
This is the problem with outdoor measurements, you don't get a true refection of in room behaviour.

My understanding is that ported subs benefit from room gain a lot less than sealed subs below port tune. I'm very happy to be corrected on that if someone can verify otherwise, but that was always my thinking.
 

Jester1066

Well-known Member
Passive radiator doesn't make it go lower, it lowers distortion.
That's not what Tom (who owns BK and designs the subs) told me! He said: I'm paraphrasing a bit

"The P12-300SB-PR will have higher overall output and hit lower frequencies than it's sealed equivalent (P12-300SB), due to the passive radiator acting like a port does on a ported sub"

That's straight from the designers lips! So I'll think I'll trust his knowledge 🙂😉👌.

He also said that the P12-300SB-PR behaved more like a ported sub in terms of SPL & frequency but in a box the size of a sealed sub. Making it ideal for those that don't have the room for big ported subs, but want a similar performance.

A truly ported sub will still be better imo than the P12-300SB-PR, for film. Assuming you have the physical space/layout to accommodate the larger cabinet size, which looking at the pics the OP does.

I got the P12-300SB-PR because:

a: I couldn't physically accommodate a larger ported sub
b: I use my system 50/50 music to movies.

I only sold it as I wanted to go dual subs and the SVS's I have are smaller. 2 of the SVS's passed the WAF, whereas 2 P12's didn't- (Nope I don't get her logic either, but ran with it and am happy!) 👍🏼😂 I don't have a dedicated room either, so that was a factor too. 🙂
 

Mr Wolf

Active Member
My understanding is that ported subs benefit from room gain a lot less than sealed subs below port tune. I'm very happy to be corrected on that if someone can verify otherwise, but that was always my thinking.
That's my understanding too. From what I've read on this subject, a sealed sub can, in the right position in the right room (the smaller the better), benefit proportionately more from room gain than a ported sub at certain frequencies and this may help narrow the gap in output between them. I'm fairly sure that this has something to do with the port's output not being in perfect phase with the driver's output so it doesn't get the full room gain effect on all of its output like a sealed sub.

That said, there's nothing to suggest that a sealed sub (i.e. with same power/driver like SVS 1000 Pro range) could ever outperform its ported equivalent in-room or anywhere else at lower frequencies. I think that would be defying the laws of physics.
 

Conrad

Moderator
That said, there's nothing to suggest that a sealed sub (i.e. with same power/driver like SVS 1000 Pro range) could ever outperform its ported equivalent in-room or anywhere else at lower frequencies. I think that would be defying the laws of physics.

I'm not so sure, and I think it's to do with the slope of the roll off.
If a ported sub rolls off at 48dB/Octave below port tune and its output is 100dB at 20Hz with a 20Hz tune, it'll be at 52dB at 10Hz and 4dB at 5Hz.

If a sealed sub rolls off with 12dB/Octave from 100dB at 20Hz you'll be at 78dB at 10Hz and 66dB at 5Hz.

With 7dB/Octave room gain that recovers quite a lot for the sealed sub (85dB at 10Hz and 73dB at 5Hz) but less for the ported (59dB at 10Hz and 11dB at 5Hz).

I'm just using those numbers as they're easy. To play 10Hz meaningfully you need more output than you do at 20Hz so in this example both subs wouldn't work that well.

My point is that room gain is going to be the same for both subs in the same room, but with a steeper slope below port tune the ported sub makes less use of that as it's overwhelmed by the roll off. A sealed sub with a shallower roll off will make more use of it. "Make more use of it" might not really be accurate, but starting from a higher position means that you end up with more output once you add room gain back in.
 

JustinT350

Active Member
Wow, that's a lot of technical info that I'll need to digest :D

I guess if I'm going to go for an upgrade I want to also future proof myself and not have to re-upgrade in a few years time.

So I think Ported would be best for my room and watching habits?
 

Jester1066

Well-known Member
So I think Ported would be best for my room and watching habits?
Agreed, as your main use is films rather than music. Have you firmed up your budget yet?

I'd definitely give Tom @ BK a call. Give him your room dimensions etc and he'll advise whether a P12-300SB-PR (or 2 is suitable for your room).

I say this because as per @Mr Wolf says: your rooms fairly big and will need at least 1 SVS PB3000 type sub, which new is £1549 RRP). 2 of the BK's come in at around £500 less if you factor in shipping etc.

There's also the BK Monoliths (which are full fledged ported subs) - From £499.95 & available in both forward & down firing modes.

In fact this - or the even bigger Monolith+ (from £599.95) - would be my choice purely on "bang for buck" It'll perform nearly as well as the SVS PB3000, but cost a lot less


Check the sizes though - as they are big beasts!

So you could get one, then add another later. Or if you were getting 1 PB3000, you could get 2x Monolith+ for around the same cost!
 

Conrad

Moderator
Are you on a solid or suspended floor?
If you're on solid (floating on concrete, for example) then ported will give you more tactile response in room. If you're on a suspended floor (an upstairs room, or on suspended joists) then you can get a similar feeling with sealed. I have that (I'm in a bedroom and my whole room can shake).

The key for good bass is integration, so something like an antimode, or a minidsp and a mic will serve you well, if that's a route you want to go down. The Denon has Audyssey and will do a pretty good job, but that can always be improved.

The whole thing about sealed being better for music and ported being better for movies is just a myth that won't die. A well integrated ported sub can sound amazing with music. Given that music is generally above a ported subs tune it's all driver anyway.

For price, you'll get more for your money with ported. For size you'll get more with sealed. You can get a 21" sealed sub in the space you can get a 15" ported, for example.

Usual advice would be to buy the best you sub you can afford now with a view to getting a second one later, rather than halving your budget across two lesser subs.
 

Jester1066

Well-known Member
Usual advice would be to buy the best you sub you can afford now with a view to getting a second one later, rather than halving your budget across two lesser subs.
+1 on this - which is why I mentioned the Monoliths as a possible option. Iirc the OP mentioned a budget of £700ish in an earlier post?
 

Conrad

Moderator
The £700 was the cost of another one of the same, as I understood it.

Monolith and the Monolith+ are great shouts, they're great subs by all accounts.

The mention of the PB2000 (£1k) might indicate that there's a bit of wiggle room in the budget? If so, these are about the best bang-for-buck in the country at the moment: Monolith 15

And if you speak to our friendly forum member @AmericanAudio there might be a forum discount.
 

kenshingintoki

Distinguished Member
in my opinion, always factor in a mini dsp 2x4HD. That thing turned my monolith plus from a bloaty mess into something .. fairly good lol!
 

Jester1066

Well-known Member
in my opinion, always factor in a mini dsp 2x4HD. That thing turned my monolith plus from a bloaty mess into something .. fairly good lol!
Next thing on my "shopping list" mate!
 

kenshingintoki

Distinguished Member
Next thing on my "shopping list" mate!


Its like witchcraft. What @mb3195 did with the mini DSP on my mono plus was insane.

it makes really good use of the headroom... combats bad room acoustics/responses really well.

also opens the gate up to the gate of godly tactile response.. the hoverBOSS!
 

Jester1066

Well-known Member
also opens the gate up to the gate of godly tactile response.. the hoverBOSS!
Still "negotiating" with the OH about a PJ & screen. My setups not in a dedicated room btw. I've a feeling I wont therefore get hoverBOSS approval!

Guessing your single 😂😉
 

kenshingintoki

Distinguished Member
Still "negotiating" with the OH about a PJ & screen. My setups not in a dedicated room btw. I've a feeling I wont therefore get hoverBOSS approval!

Guessing your single 😂😉



Hahaha yup! very single lol. Hoverboss can be well hidden tbh mate. More worried about hiding a subwoofer lol.
 

Coulson

Distinguished Member

Jester1066

Well-known Member
Hahaha yup! very single lol. Hoverboss can be well hidden tbh mate. More worried about hiding a subwoofer lol.
Just trying to imagine her reaction, when sofa starts vibrating! 😂😂😂😳!

Anyway, must stay on topic!
 

JustinT350

Active Member
The £700 was the cost of another one of the same, as I understood it.

Monolith and the Monolith+ are great shouts, they're great subs by all accounts.

The mention of the PB2000 (£1k) might indicate that there's a bit of wiggle room in the budget? If so, these are about the best bang-for-buck in the country at the moment: Monolith 15

And if you speak to our friendly forum member @AmericanAudio there might be a forum discount.

£700 was just plucked based on the cost of a pb1000 Pro, or pb2000.

My current sx120 is a cheap and chearful £150 job.
 

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