Advise, Kef Kube 8b Bottoming Out (HT setup)

SamL

SamL

Audiophyte
Hello,

I'm having issues with my Kef Kube 8b and wonder if anyone could help?

In my Onkyo txnr 737 receiver I have my crossovers set to 80hz for my Left, right and Centre the other speakers are set to 120hz. LFE set to 120hz
i have ran the automatic calibration and have gone back to the speaker calibration and checked the pink noise and corrected to 79db (auto calibration every time sets my L&R speakers to 74db the reset are not far off 80db) i've been generous and and set my sub to 81db using my SPL meter weighted to C.

On the sub panel i have the crossover set all the way to 140hz/LFE, Volume at 12 O'clock, 0' phase and the EQ is set to In Room (other options are In cabinet or In Corner)

Single sub setup. (i have been thinking about getting another one)

Room size is around 170 square foot (encase that helps in some way)

I normally listen to films at -30 to -25 on the receiver volume.

I sometimes get and what i can best describe as a popping sound during really deep rumbling bass scene from my sub. A good example where i here popping sounds is the film Ready Player One during the scene near the end where Sorrento activates the grenade devise sending out a shock wave which wipes out all the players in the game apart from Parzival. (which I counted around 10 pops) TBH I don't normally here popping sounds when watching films that i have noticed.

So i have done some troubleshooting. I disconnected all my speakers apart from my sub and replayed the same scene from Ready Player One over and over while decreasing the sub gain in the AV to where the popping stops. Which then reads around 73db on the SLP meter when listening to pink noise. I also play Played the Film Midway (2019) and Blade Runner 2049 while set to 82db in pink and skipped to the bass scenes throughout the films and don't get any pops.

So do i set the pink noise to 72db or leave it around 82db and just put up with the popping if and when it happens, anything that i could do to help stop this, is the sub possibly faulty or just need a better sub?


Any advise would be great.

Kef Kube 8b Specs:
WEIGHT
11.3kg

DIMENSIONS
(with Rear panel and feet / H x W x D)
293 x 293 x 310mm (11.5 x 11.5 x 12.2in.)

DESIGN
Powered Subwoofer (sealed)

POWER REQUIREMENTS
100V - 120V / 220V - 240V ~ 50 / 60Hz

UNIT MEASUREMENT
Piece
VARIABLE LOW PASS FILTER
40Hz - 140Hz & LFE

FREQUENCY RESPONSE
34 to 140Hz (-6dB)

MAXIMUM OUTPUT
105dB

AMPLIFIER POWER
300 Watts RMS

AMPLIFIER TYPE
Built-in Class-D
DRIVE UNITS
1 x 200mm (8in.)

INPUTS
RCA phono sockets Speaker level inputs

ANALOGUE INPUT
RCA phono sockets Speaker level inputs

DOCUMENT DOWNLOAD
 
XEagleDriver

XEagleDriver

Senior Audioholic
So do i set the pink noise to 72db or leave it around 82db and just put up with the popping if and when it happens, anything that i could do to help stop this, is the sub possibly faulty or just need a better sub?
Sorry to say, but a Kube 8b is not a real subwoofer. With only an 8 inch driver, a mere 300W amp, in a very small 1 cu ft enclosure it is just a glorified woofer.

Therefore, since you like movies and bass I would replace it with at least a 10" ported sub, but preferably a 12" ported sub.

In the mean time, turn the sub volume down into the 70s to avoid damaging what you have now.
Cheers,
XEagleDriver

Sent from my SM-G975U using Tapatalk[/quote]
 
SamL

SamL

Audiophyte
Sorry to say, but a Kube 8b is not a real subwoofer. With only an 8 inch driver, a mere 300W amp, in a very small 1 cu ft enclosure it is just a glorified woofer.

Therefore, since you like movies and bass I would replace it with at least a 10" ported sub, but preferably a 12" ported sub.

In the mean time, turn the sub volume down into the 70s to avoid damaging what you have now.
Cheers,
XEagleDriver

Sent from my SM-G975U using Tapatalk
[/QUOTE]
Yeah i was afraid of that :( thanks for your response.
was looking at adding another Kube 8b but failing that iv been been looking at the Klipch r-115sw as a replacement.
 
ryanosaur

ryanosaur

Audioholic Spartan
This entire series Shady wrote up is great, but when shopping for Subs, it's important to look at the Frequencies you want to reproduce, and the performance at those frequencies.
Driver size does come into play, but not as much in a well designed driver: there are 12" subs that can outperform 15" subs, for example.
Rather as you learn to understand some of the Data, you can see exactly how loud and at what SPL a Subwoofer can perform!
I agree with XEagle about the KEF.

I would further add caution about buying Klipsch!
Some have said that a few of their models perform decently. I wouldn't spend money on that. *shrugs

The advice I embrace is to buy the best single sub you can allow yourself to afford. I would start with the Hsu VTF2, frankly. I think, and many seem to agree that it is one of the best values for your Dollar in terms of performance.

That said... how big is the space you are in for your HT? The total open room volume is what is important

Cheers!
 
SamL

SamL

Audiophyte
This entire series Shady wrote up is great, but when shopping for Subs, it's important to look at the Frequencies you want to reproduce, and the performance at those frequencies.
Driver size does come into play, but not as much in a well designed driver: there are 12" subs that can outperform 15" subs, for example.
Rather as you learn to understand some of the Data, you can see exactly how loud and at what SPL a Subwoofer can perform!
I agree with XEagle about the KEF.

I would further add caution about buying Klipsch!
Some have said that a few of their models perform decently. I wouldn't spend money on that. *shrugs

The advice I embrace is to buy the best single sub you can allow yourself to afford. I would start with the Hsu VTF2, frankly. I think, and many seem to agree that it is one of the best values for your Dollar in terms of performance.

That said... how big is the space you are in for your HT? The total open room volume is what is important

Cheers!
thanks for your reply!
The room is 34.77 cubic meters, W3.6m L4.2m H2.3m
 
SamL

SamL

Audiophyte
mmm... metric.
Hsu will likely not be an option.

Whereabout are you located?
England UK.

Just looking at the SVS PB1000 now, but i think I will wait for the demo rooms to reopen before blindly purchasing, hopefully in a couple of weeks all going to plan.


Cheers
 
William Lemmerhirt

William Lemmerhirt

Audioholic Spartan
Indeed, where are you located? That kube8 is a small
Music oriented subwoofer. It’s very small, and the listed low FR point is 34hz. I’d guess that’s f6 but could be f3. In any case, it seems like you enjoy bass heavy films. RP1 is well known to have a great track, and heavy bass. Add in that your +6db hot, that poor thing doesn’t have a chance lol. The good thing is that the room isn’t huge, as long as it’s not connected to other parts of the house. What that means is while you shouldn’t consider any more kubes, a decent 12” or 15” with good extension should set you straight.
 
Pogre

Pogre

Audioholic Warlord
England UK.

Just looking at the SVS PB1000 now, but i think I will wait for the demo rooms to reopen before blindly purchasing, hopefully in a couple of weeks all going to plan.


Cheers
SVS is a great start. If you're looking at the PB1000 I would plan to get 2 of them. Your space isn't huge, but the 1000s aren't either. I'd want ported too.

As to your KEF cube, yes. It's just being asked to play harder than its capable of. Speaker manufacturers tend to fall down on making subs. I think XTZ makes some pretty good subs too and might be a little more budget friendly.
 
William Lemmerhirt

William Lemmerhirt

Audioholic Spartan
Forgot mention, seems like you have a good handle on your settings and setting up a new one should be easy.

FWIW, I would bypass the pb1000. If 500 is your hard limit, the monolith10 by monoprice is a better subwoofer(but not by miles). If you can spend a little more, the pc/pb2k is in the outlet for 700 and is a great deal for 700 dollars. I don’t know what that looks like for you, or if the outlet is available in the UK, but it’s worth the money if you can swing it.


Also, over in your parts, XTZ is very reputable although I’m not greatly familiar with their lineup. I think the 12.17 looks like a good fit for budget.

 
SamL

SamL

Audiophyte
Forgot mention, seems like you have a good handle on your settings and setting up a new one should be easy.

FWIW, I would bypass the pb1000. If 500 is your hard limit, the monolith10 by monoprice is a better subwoofer(but not by miles). If you can spend a little more, the pc/pb2k is in the outlet for 700 and is a great deal for 700 dollars. I don’t know what that looks like for you, or if the outlet is available in the UK, but it’s worth the money if you can swing it.


Also, over in your parts, XTZ is very reputable although I’m not greatly familiar with their lineup. I think the 12.17 looks like a good fit for budget.

This looks good thanks for the recommendation, the 10.17 size would be manageable with the space i have to place one. Ported seem to be deeper that non ported :(
 
William Lemmerhirt

William Lemmerhirt

Audioholic Spartan
This looks good thanks for the recommendation, the 10.17 size would be manageable with the space i have to place one. Ported seem to be deeper that non ported :(
Indeed. Ported subs will always be larger, but so is their performance. I’m not a fan of sealed subs personally, although there are rare occasions...lol
While the 10.17 will physically fit better, I think with your penchant for bass, once you get a taste of real deep smooth linear bass, you’ll want to upgrade again. Maybe not, but it is many times the case.
 
lovinthehd

lovinthehd

Seriously, I have no life.
BK Elec subs would be another consideration for your location.
 
TLS Guy

TLS Guy

Audioholic Slumlord
England UK.

Just looking at the SVS PB1000 now, but i think I will wait for the demo rooms to reopen before blindly purchasing, hopefully in a couple of weeks all going to plan.


Cheers
Since you are in the UK you might want to take a look at BK subs at Southend on Sea. They have been in the business for some time. They are direct order, and their subs have a good reputation and they offer good value for money.
 

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