My Kef TDM 45B has very recently given up the ghost after over 20yrs of faithful service. 
 Have been looking at replacements for my subwoofer and wanted to see if any of our members here had any experience to share on the subject. 
My HT room is 28ft x 14ft x 8ft. 
My Av processor is a Yamaha and I think I’ll renew it to the A8a while I’m updating the system as well. 
So far I’m leaning towards the SVS range of subwoofers. If I keep my current processor I can run one sub. If I update it, I can run two subs. 
So I’m leaning towards either same processor with a PB16 or the new PB17, or change the processor and add 2 PB4000 units. 
The new PB17 may now reduce the price of the PB16 ultra, so that might be a consideration for dual use as well. 
Im thinking Ported is the way to go now that I’m updating the system. 
All comments and suggestions are very welcome so I can make an informed decision please. 

Edited 10 December, 20241 yr by UndertheRadar
To correct measurements

Sounds like a subject @Lady Elanore could get her teeth into.

When I saw the subject "AV update" I thought Anti-Virus update not Audio-Visual update 🙃

When I blew my Epos sub up a while back....     I opted to replace it with an SVS Sub. My room isn't particularly big and is rather squarish in plan view, so bass control was more important than ultimate window rattling. As it happens, I can not only rattle windows, but cause things that live on less substantial fixings to rotate!!

 

I went with the SVS SB3000, which is the Sealed Box version as opposed to the ported SVS PB3000. The bass goes pretty deep owing to the driver being almost 14 inches across and the amp peaking at some ridiculous number. But the best bit is the Bluetooth integration they have as standard. I lined the Sub up using the Audyssey app on my receiver (Denon 4700) and then tailored the response a little. But further tweaking using the Subs app ,rendered even better results in some ways and it integrates with my floorstanders beautifully now. If you run a frequency sweep, there isn't really a noticeable peak as the Sub moves over for the floorstanders. Very smooth. But if I want it to go full weapons grade, it's a button press in the phone app and hey presto, I can make the neighbours come round to visit me, PRONTO!   

 

I'm pretty sure 2 x PB4000s will be more than enough, unless you really do like to bring bits of plaster down from the ceiling. They really are superb and surprisingly articulate for such large drivers. I'd try and get a demo and perhaps look at 2x 3000s as well as the 4000s 

I should add that if you are running two subs to even up the imaging (LF imaging being rather indistinct owing to its low frequency) then you could simply run the RCA out of the first sub and daisy chain them. 

Thank you for your input. Very much appreciated. My old Kef was a sealed unit, but I had thought given the specs of the SVS units, and after considerable googling and review reading, that I could maybe cover the best of both worlds with the PB units. 
If I am correct in my understanding, the app allows for correction when the ports are bunged. So is it as simple as bung and adjust for music and remove bungs and adjust app for movies. 
would that be a reasonable assumption or is my thinking flawed in your highly regarded opinion? The costs are a bit much to mess this up!!
I can’t find anyone over here that can demo any of the units at all. My main hi fi/AV specialists all want to sell me something different. Mainly Rel, earthquake and Kef, so I may have to just make an informed decision and order myself without going though them. 
I have the room cabled with conduit runs in wall, so I’m already running dual sub feeds, but I used a small 8” M&K along with my centre rather than both from sub channel. So setup would be rear left corner and front right corner if I then run the full 11.2 setup. 
my heads wrecked to be honest, as I can’t listen to any of them here. The SB 16 ultra is being discontinued for the new 17, and I’m pretty sure I’ll shortly find an sb16 at similar money to the pb4000. If I could actually hear them or get a demo in my own house I could make an informed decision on whether to go ported or sealed, larger and single or smaller and duo etc. 

Really wishing my old sub just still worked like it used to. 😞

I have the sealed box, with no ports. This gives a more controlled response at the expense of extremely low bass. Don't get me wrong, there is a lot of very, very low bass, it is a massive driver after all. The ported version goes a tad deeper, has more punch and volume but has a slightly more uneven response. I guess what I'm saying is I don't know about bunging and unbunging the PB4000 as it isn't a feature on my Sub. But the app allows for tailoring between movies and music etc, so can be adjusted from your armchair. It also controls level and several other features. The rear of the sub has a lot of adjustability too, but most of it is covered in the app. 

 

You could get a PB4000 and see what you think. If you like it then consider a second one, if not return it. It is quite a beast. I don't know how loud or good, your old Kef was, but I suspect you will be more than pleasantly surprised by the SVS. I was amazed at the punch compared to my old Epos sub.  I'm pretty sure you won't be disappointed with an SVS sub, they are superb and the whole range gets glowing reviews.

 

 

Here is a SB4000 review

 

Here is a PB4000 review

 

 

@Lady Elanore No one has any Svs units for me to try out, but one of my locals today has said they can bring me one in if I so wish. 
they have loaned me a Kef KC92 in the mean time for reference as to work out what I need, and obviously to try it out as well. 
I must say the tightness and punch from the KC is really nice and way punchier than my old 45b. It sounds brilliant with music and a few blu rays that I’ve flicked through for reference to get the full effect. As good as it is, there’s just something missing. I think it’s the fact the bass from the KC hits you in the chest. You can feel it far tighter than my old 45b, but I’m missing the fact the floor and the settee doesn’t vibrate any more from the really low stuff. I may ask them their opinion on whether they think the Svs can do both, as they have fitted them to some of their higher end installs so I have the tightness and the low end vibration. Other than that, I may be back to 2 subs so I can have a smaller one set for tightness and punch and the larger set for low end grunt and vibrations. Should be achievable if I set the room correctly and get the crossovers just right. 
it has given me something to think about anyway. 
Again, thank you for your help. Much appreciated. 
 

Edited 11 December, 20241 yr by UndertheRadar

I think you do need to hear the SVS. They pack a huge amount of punch and really are quite articulate. Plus they make everything not tied down jiggle 

 

I found the SVS sub to be a bit of a game changer, a genuine world leading bit of kit. The 4000 would probably blow candles out a couple feet away once its up to speed. 

I've had a look at the Kef and if I'm looking at the right model and getting my sums right, the SVS cone has roughly twice the surface area of the Kef and that's including the fact that the Kef has twin drivers. I think with the cabinet being sealed and the drivers acting in opposition to each other, it may well give great control but will limit the sheer amount of air that can be moved. You would probably want the twin drives of the Kef to work with opposite polarity if you wanted to shift the air more easily, ie like the Linn Isobarik, but this would almost certainly cause phase cancellation owing to the LF nature of a sub 😞 

 

Please take the local dealer up on their offer to try the SVS. Especially if they are going to cart it round for you (it's pretty heavy and quite big)  I'll be amazed if you are not impressed with it. It even looks like something Darth Vader might have in his HiFi set up 

Just by way  of an update. I’ve ordered an SB17 ultra evolution to make sure my low end is covered. I’m not just totally convinced it will cover the mid bass as tightly as I’m hoping, so I have asked for an SB2000/3000 on standby incase in need to add it at the front to cover me for chest punch. 😂

I’ll report back once it’s here and up and running. On a pallet and being shipped on Monday. Whether it makes it here before the holidays is anyone’s guess. 

1 hour ago, UndertheRadar said:

Just by way  of an update. I’ve ordered an SB17 ultra evolution to make sure my low end is covered. I’m not just totally convinced it will cover the mid bass as tightly as I’m hoping, so I have asked for an SB2000/3000 on standby incase in need to add it at the front to cover me for chest punch. 😂

I’ll report back once it’s here and up and running. On a pallet and being shipped on Monday. Whether it makes it here before the holidays is anyone’s guess. 

 

Good grief! That's a weapon and a half. You went all in there  You'll need to give it a separate mains feed  2 x massive voice coils. Lord, that will shift some air, even with a sealed cabinet.

 

I'm fascinated to hear what you think of it. Hopefully it will be articulate enough for you, I'm sure it will be loud enough. I also hope your back is strong as that thing must weigh more than I do! 

2 hours ago, Lady Elanore said:

 

Good grief! That's a weapon and a half. You went all in there  You'll need to give it a separate mains feed  2 x massive voice coils. Lord, that will shift some air, even with a sealed cabinet.

 

I'm fascinated to hear what you think of it. Hopefully it will be articulate enough for you, I'm sure it will be loud enough. I also hope your back is strong as that thing must weigh more than I do! 

As soon as it’s in place and I’ve had the chance to listen to a few different styles of movie and music I’ll report back. Reason for choice was, it’s big and sealed and they’re claiming some serious levels from both low end and mid bass. That along with the fact it’s new and as you stated, it has a very interesting voice coil construction that I’m hoping helps to seriously compose the sharpness of the mids. 
the other reason was that we’re pretty sure the 4000 series is being updated next year to a similar style but slightly less than this new 17ultra, so I’d be paying full price for two 4000 series that would be out of date (still very good) in a short period of time. 
The Av Processor is in a similar position. We are also pretty sure that Yamaha is updating its AV range in 2025 as well. They seem to be heading more high range. They have released a very nice very well made range of stereo amplification recently, with some very very well made components. Like the old school Yamaha amplifiers with milled aluminium knobs and such. I’m hoping they make an attempt at heading their new range of AV processors in the same direction, so I’m very happy to run mine another while to gamble on whatever they come up with. 
The 17 ultra is coming in the retailers van with one of their installers. Hopefully the two of us can manage it into position. Should have maybe said my room was purpose built above the garage, so has to go up a flight of stairs. 😂

Ive a JCB with pallet forks on standby just in case. 
Thankfully its the sealed unit, the ported looks like an absolute disaster to handle. It must be nearly a third the size of the sealed again. 

Edited 13 December, 20241 yr by UndertheRadar

44 minutes ago, UndertheRadar said:

As soon as it’s in place and I’ve had the chance to listen to a few different styles of movie and music I’ll report back. Reason for choice was, it’s big and sealed and they’re claiming some serious levels from both low end and mid bass. That along with the fact it’s new and as you stated, it has a very interesting voice coil construction that I’m hoping helps to seriously compose the sharpness of the mids. 
the other reason was that we’re pretty sure the 4000 series is being updated next year to a similar style but slightly less than this new 17ultra, so I’d be paying full price for two 4000 series that would be out of date (still very good) in a short period of time. 
The Av Processor is in a similar position. We are also pretty sure that Yamaha is updating its AV range in 2025 as well. They seem to be heading more high range. They have released a very nice very well made range of stereo amplification recently, with some very very well made components. Like the old school Yamaha amplifiers with milled aluminium knobs and such. I’m hoping they make an attempt at heading their new range of AV processors in the same direction, so I’m very happy to run mine another while to gamble on whatever they come up with. 
The 17 ultra is coming in the retailers van with one of their installers. Hopefully the two of us can manage it into position. Should have maybe said my room was purpose built above the garage, so has to go up a flight of stairs. 😂

Ive a JCB with pallet forks on standby just in case. 
Thankfully its the sealed unit, the ported looks like an absolute disaster to handle. It must be nearly a third the size of the sealed again. 

I had a look at a review of it and see the LF only rolls off a little as it gets to 15hz  64ft organ pipes are going to sound supersonic!!!!!!! 

 

Hope your garage is reinforced  and I'm not just thinking about the weight of the sub

You might like this hot of the press review...

 

 

 

a lot!

 

 

Looking forward to getting it now the more reviews i manage to find and watch.
Would be great to have it here and set up for watching movies over the holidays with the family, so fingers crossed. 
Although now Ive started looking up atmos ceiling speakers and reviews on new main fronts and centre. 
i think its sparked a HT room update next year, as i tend to just leave things in place as long as they still work and dont always keep up on the newest version unless something goes wrong and needs replaced. 
 

I put a couple of Atmos in to see if it was worth going the whole hog and to be honest I was a bit "Mehhh" 

You occasionally get the "ooh it's a helicopter" moment, but mostly it just sort of adds to the vagueness of all encompassing stuff. Crowd fx, some sorts of music etc. It does enhance things a little, but I think I'm with Christopher Nolan on it. He doesn't record Atmos soundtracks (although I'm sure studio pressure will change this). He prefers a DTS Master Audio approach, and I prefer this to be honest. Atmos is here to stay, trust me, I rig the bloody mics for it most days at work. But I think it's more of an "ooh that's neat" kind of thing 99% of the time. 

 

The encoding of the soundtrack in Atmos (as opposed to referring to the ceiling speakers) rather than simply leaving it as 5.1, 7.1 etc is a clever thing and I see the benefits. But more isn't necessarily better, I don't think. 

In all honesty I’m more than happy with the 7.2 setup at the minute, although I’ve the wee M&K sub at the front set to run along with the centre channel to give it more weight and will probably leave it that way when the 17 arrives. Can’t see me needing more LF than that monster. 
My processor really does need an update, and my HT room is upstairs above the garage, with all the walls already ready with extra conduit for more cables. So it’s no hardship to cut 4 holes in the ceiling and make up and drop an extra 4 cables down the wall. They’ll be in and wired, and if they’re used they’re used, and if not, so be it. 
I think maybe updating to the new Q11 meta’s and Q6 meta when the processor is updated would give the room more of a lift with a bigger soundstage. 
Might be in my head though, so I’ll borrow the new fronts to try them first, and I may not need to do it at all, as a DTS HD MA codec sounds really good at the minute with a set of 15yr old kef’s, and every now and then my 30yr old missions get a run. 

So, as it turns out for whatever reason, I went down today to pay for the woofer before it lands, and the shipping docket is showing a PB17 as being on its way instead of a SB. 
I think LeeLoo said it best

”Big Badaa Boom”

might need to plug some of the ports. 

Holy Cow!! That can shift mountains if the reviews are to be believed. Can't wait to see what you think of it. 

 

(DTS HD MA is my favourite codec    is it weird to have a favourite codec?)

 

 

Edited 18 December, 20241 yr by Lady Elanore

It’s shipped and should be here before Friday hopefully. I should hopefully have it by Monday at the latest. Absolutely, definitely need help to place it, as it’s completely mahoosive!! 
I would favour HD MA as the detail is just a step up from the others. But given I haven’t fitted the atmos yet, I can’t comment on it. I’ll add it when I update the processor, and then I can make a choice as to what codec to use when viewing. 
listened to some R11’s while there today as well, with a view to replacing my Q9’s. They were a bit confused when I said the sound I was trying to match and slightly better was a 30yr old set of 753’s. Something about them just sets such a fantastic soundstage, that I have been able to replicate since, and I’m scared of these blowing at higher volume and me being very very sad. 
I will report back with a pic or two (obviously with a banana for scale) and a few words on how I think it performs. But I’m almost sure the PB will produce enough LF for most of the village to feel it. 

I was going to use a banana for scale but needed a bunch so you could actually see them. Things massive. 
only took 3 1/2 hours to get it from the car up the stairs and in place. It’s unreal as far as weight and moving is concerned. 
needs something like 600 hrs to run in properly and I’m trying to go through all the settings on the phone app at the minute to set it up. More used to a frequency and level at the back than a full page of settings on an app, so don’t have it running at its best yet. 
ill have to report back once I have it room corrected. 

I think you should plug the ports with bananas, find a movie track with many explosions and see how far you can fire the bananas across the room. A sort of 'Sub' machine gun for bendy yellow fruit 

 

 

Seem to have it well dialled in now. 
Sitting at -6 db at 90hz with a 24db slope and the ports all set to open with no bungs. 
So far the only word to explain it is phenomenal. I’m sure there’s folks in the village still under their tables for cover and the street lights haven’t tripped back on yet. 
No joke, while adjusting and testing the settings, the dogs ball that was sitting on the settee started to move across the seat. Never had or listened to a subwoofer that could move this much air. It’s an absolute animal. It can not only dish out very low frequencies, but it can also give a very detailed and controlled mid range kick as well. 
Set movies with Aquaman submarine surfacing,  John wick nightclub scene and the opening scene of Transformers age of extinction. All played in DTS HD MA. 
Cant wait to watch a full movie, this thing is an absolute game changer of a subwoofer. 

I felt the same with my smaller 3000. Amazing thing, especially for the money. I have mine dialled down most of the time out of respect for my neighbours. But if I know they are out....

 

 

KABOOM!