BK Gemini Mk2

nenito2k

Active Member
@Gasp3621 will do and report back; still lo level gain at 12 o'clock should be "ok" and not give me -10db....

will try that button at 10 o'clock and see if i can get YPAO gives me -6.5 or - 7.5db....
 
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Gasp3621

Distinguished Member
@Gasp3621 will do and report back; still lo level gain at 12 o'clock should be "ok" and not give me -10db....

will try that button at 10 o'clock and see if i can get a calibarted level of -6.5 or - 7.5db....

Make sure you turn the correct knob as there is two, one for high level connection and for low, so lo level gain is the correct one. :)
 

vitw1844

Standard Member
I would just like to share this post as some may find it relevant/interesting. I have had a BK Gemini II sub for seven years, mainly used for high quality studio monitoring at a video editing desk. A few weeks ago one of the capacitors went. Rather than having it fixed, for now I have bought a new one in Black Ash. I will keep the other one as a spare.

What I have noticed, twice, is that when new the sub measures in my room to go down to around 28Hz before it is inaudible. Once it has been used over time it easily goes down to around 22Hz. I have the new sub set at the same level as the old, like for like settings. This is with the crossover frequency set at 85Hz and the low level input just slightly above the 9 o'clock position.

At this setting, with the old sub, after a period of time, the 30Hz frequency made the windows rattle. With the new one, as it was with the old at first, there is output at 30Hz, but not so strong.

In time the driver loosens up and bass becomes more responsive. I post this as some people believe that subwoofers need no break in time, but in my experience they do.

In essence, if your BK Gemini II sounds a smidgen flat at first, give it time to become more powerful and you will be rewarded with sub 30Hz output, output not to pressurize the room greatly, but enough to hear the air and to make a difference when listening to recordings/films in a small room. All the best with this little "Gem".
 

nenito2k

Active Member
@Gasp3621 here is my report back after what you said: now calibration of my gemini is -7db :) your advice was indeed the solution : i turned the lo level gain to less than 10 o'clock (as 11 and 10 still gave me -10db and -8db :confused:)
 

vitw1844

Standard Member
Has anyone had this happen before? I had set my new Gemini II sub with the exact same parameters as the old one, and in the same position, but noticed that things were not sounding as solid as they should. The overall sound was a little hollow, and slow. I then changed the phase from 0 to 180 and noticed the sound came back into shape again, as before, the bass sounding in time with the midrange. What I did not realize is that even though a subwoofer is of the same model and make, two different samples can have phase differences with the mains, even though they are set at the same parameters, and positioned in the same place. A new lesson to be learned for me - not to assume that two identical subwoofers from the same manufacturer produce output in identical phase with the mains.
 

nenito2k

Active Member
@vitw1844 how can i know exactly if i have to choose 0 or 180 for phase ? o_O did not really see differences...of maybe i should test with music ?
 

vitw1844

Standard Member
Greetings nenito2K, use music with wide ranging bass content, and whilst listening turn the phase control to 0 first, then listen, then round to 180 and listen. Keep the same song playing and change accordingly. When in phase the sound will have more bass content and the bass will be in time with the rest of the music. To keep it simple, less bass = out of phase, more bass = in phase. Why? When the subwoofer is in phase with the other speakers then it will add to the sound and reinforce the output of the main speakers. The sound waves will not cancel each other out. If there is not much difference then the subwoofer is located in a place where there are the least cancellation effects in your room.
 
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nenito2k

Active Member
i see; will test soon as i only tested quickly with movies.... probably not a good test from what you say Now i only have RAP/HIP HOP music and bass should be GOOD on some titles :)
just to make sure i understand this phase stuff (while sitting in the sweet spot)

- i play the track twice (on each phase)
- i listen for the time the bass is more present
- this will also be valid for movies ?
 

vitw1844

Standard Member
There is no need to play the track twice on each phase, keep the track playing and whilst playing first turn to 0, sit and listen, then turn to 180 and sit and listen. That way you can have a clearer audible immediate indication as to which sounds better. You can check this way or the way you mentioned, but I find by changing the phase whilst something is playing I can more easily determine which setting is right. I have never used my sub for movie watching, only audio monitoring, but yes, it will be fine to test via movies.
 

nenito2k

Active Member
@vitw1844 did some test on NICKI Minaj yesterday (mp3 @320kbps) and really i can't tell any difference between phase 0 or 180....or it is very slight to notice. what i realised is that bass is light on most of the album and it should not be...as i know the songs from my 25$ headphones !
something does not sound right...will do more tests...

if memory serves me well there are special samples to test EXCLUSIVELY one's LFE channel...don't recall were to find them; will look around the net; if you have a clue, please advise :)
 

vitw1844

Standard Member
Hello nenito2k, if your system is sounding bass light when playing music then it is down to how your amp is set for bass management when playing stereo. Have you tried other tracks through your system to see how they sound? Have you tried playing a movie with a lot of bass content? There are various options that you can try to see how the subwoofer sounds with various bass content. Another way to set up the phase is to run a test tone of say 100Hz and see how changing the phase makes it sound. Experimentation is the key to success in the audio world. The effort will be worth it in the end.
 

nenito2k

Active Member
well i tested many tracks: rap, rock and classical sometimes bass is better but remains light...will do more testings; in the meantime i found this which could help me (and others)


@vitw1844 good idea for a test, but should it not be a tone below 100hz to really have bass :thumbsdow ?
 
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nenito2k

Active Member

vitw1844

Standard Member
100Hz is a good frequency to use as it can be heard from both mains and sub. Remember that the speakers reproduce frequencies above and below the crossover point. By dialling in the sub to blend in and just slightly augment the 100Hz tone then you have a fairly good proximation of seamless intelgration of sound. 100Hz is the middle of upper bass (midbass). Basically 20-50Hz = lower bass, 50-100Hz = midbass, 100-200Hz = upper bass. If the sub is interfereing with the 100Hz sound of the mains too much =muddy sound in the midbass. Do you see the idea?
 
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nenito2k

Active Member
@vitw1844 ok i downloaded the samples from the site i gave above here is what comes out (sit in the sweet spot):

- 20hz : not audible at all on the gemini 2....0 or 180 phase
- 40hz: 0 or 180 phase does not make any difference
- 60hz: 180 phase is a little louder/more presence and seems wider
-100hz: 0 or 180 phase does not make any difference

at the end because of the 60hz test i settle on 180° phase...is all this "normal" ?
 

nenito2k

Active Member
@vitw1844 i need a hand...

like i said i needed to put the volume knob on the sub a 9.30 o'clock in order to get -7db ; like i said i now have a low level volume bass on music and movies & games... so :

1: should i up the volume on the sub now to 12 oclock ?
2 : should i push up the sub volume LEVEL on the AVR ?
3 : should i push the overall volume on the REMOTE (all speakers...) ?
 
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vitw1844

Standard Member
Greetings nenito2k, once you have the sub set at the correct level, then yes, increase the volume of your source components, i.e. pre-amp and remote. The Gemini II is a sealed box sub, thus it adds clean low bass to the main speakers, and does not pressurize the room like a ported sub does. It is more about accuracy and subtlety rather than forceful output, but it has plenty of power when needed for a smaller room, and will reach lower, in a controlled way.
 

nenito2k

Active Member
@vitw1844 i am confused... did you mean i should opt for 2) or 3) :confused: ?
in scenario 3) i still feel SUB is weak....
in scenario 1) that you did not advise....all seems GOOD now...but...did not try option 2) yet
 
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vitw1844

Standard Member
Hello nenito2k, lets start again. I am sorry if I seemed to confuse you. If your bass level sounds low, the simplest way to setup your sub is to first play your main speakers at your normal listening level and then set the sub level on your pre-amp to the recommended level by the manufacturer, then finally set the high/low, crossover, and phase levels on the Gemini II so that it blends in with the mains and gives the required output you are satisfied with in your room. The level you set on the Gemini in your room will be determined by its position in your room and where you are sitting. If all is still not to your liking, go by your ear more than technical readouts as there are too many variables in different rooms in different homes. It is all about experimentation. The user manual for the Gemini II recommends the same as I have mentioned. I do hope that you can tune your system to your satisfaction. I do not use my subwoofer in a home cinema setup, but for nearfield monitoring. I have a 2.1 setup, thus all I do is to set the subwoofer to a level to match the mains at my normal listening levels. I keep it simple. I shared my experience in this thread to, hopefully, help others to setup theirs. Your setup is different and your room is different. If you keep to these simple steps then you should soon have your system balanced.
 
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ChaosFlower

Novice Member
Hi. New member, though I am sure over the years I have read stuff on here.

Anyway, I was looking at the Gemini 2 and I found this thread.. 10 years this thread has been going!!

After 3 decades of owning hi-fi I have decided maybe I'd like to experiment with a sub. for my small living room 12ft by 10ft. My set up in that room is Arcam Alpha 10 amp, Mission M74 floorstanding speakers.. I have a 50in plasma also, and I like decent sound for movies, but primarily I am a 2 channel music guy.. well soon to be 2 channels and a sub... movies and music I prefer simple.. I just want the sub for a bit more thump. I will not be adding more speakers.

My speakers are aggressively toed in about 40 degrees along the longest wall and so fire across the narrowest length of the room.. which after much messing seemed to work best.

Questions.. do I use the low level or high level inputs? My amp has preout and power in phonos that are not connected (no bridge necessary). If high level do I put the high level neutrik cable on SP1 or SP2? If I put it on SP2 doees that mean I can disconnect the sub when not needed by switching off SP2? Is it correct you should turn the sub off before you turn the amp off? Will connecting that piggy back neutrik cable to SP1 or SP2 degrade my sound in anyway or cause stress to the amp i.e. effect impedance?

Am I right in thinking the Gemini has a toroidal supply and is class A/B?

Am I right in thinking that metal plate with the knobs and display on etc likely doubles as a heatsink? Obviously I have noticed higher models in the range have additional finned heatsinking attached..

Anyone look inside? What electrolytic caps do BK use? I found a hazy picture of someone disassembling a gemini and it looks like they did or do use Samwha for the main filter caps.. which is good.. I'd prefer to see Japanese Rubycon, Nichicon, Panasonic.. but the Arcam Alphas used Aerovox, Rubycon, Taicon, Samwha.. and the South Korean Samwha appear to have very good longevity... I just don't trust Chinese electrolytics. Not yet anyway.

What kind of settings am I likely to probably settle with?

Thank you
 
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stuproberts

Active Member
Hi. New member, though I am sure over the years I have read stuff on here.

Anyway, I was looking at the Gemini 2 and I found this thread.. 10 years this thread has been going!!

After 3 decades of owning hi-fi I have decided maybe I'd like to experiment with a sub. for my small living room 12ft by 10ft. My set up in that room is Arcam Alpha 10 amp, Mission M74 floorstanding speakers.. I have a 50in plasma also, and I like decent sound for movies, but primarily I am a 2 channel music guy.. well soon to be 2 channels and a sub... movies and music I prefer simple.. I just want the sub for a bit more thump. I will not be adding more speakers.

My speakers are aggressively toed in about 40 degrees along the longest wall and so fire across the narrowest length of the room.. which after much messing seemed to work best.

Questions.. do I use the low level or high level inputs? My amp has preout and power in phonos that are not connected (no bridge necessary). If high level do I put these on SP1 or SP2? If I put them on SP2 doees that mean I can disconnect the sub when not needed by switching off SP2? Is it correct you should turn the sub off before you turn the amp off? Will connecting to SP1 or SP2 degrade my sound in anyway or cause stress to the amp i.e. effect impedance?

Am I right in thinking the Gemini has a toroidal supply and is class A/B?

Am I right in thinking that metal plate with the knobs and display on etc likely doubles as a heatsink? Obviously I have noticed higher models in the range have additional finned heatsinking attached..

Anyone look inside? What eletrolytic caps do BK use? I found a hazy picture of someone disassembling a gemini and it looks like they did or do use Samwha for the main filter caps.. which is good.. I'd prefer to see Japanese Rubycon, Nichicon, Panasonic.. but the Arcam Alphas used Aerovox, Rubycon, Taicon, Samwha.. and the South Korean Samwha appear to have very good longevity... I just don't trust Chinese electrolytics. Not yet anyway.

What kind of settings am I likely to probably settle with?

Thank you
The Gemini II comes with a neurtalink cable that connects to the speaker terminals on your amp and to the high gain connection on the back of the sub. For music only this is the recommended way to run it (although experimentation is advised for every user). From what most people say on this forum, set the high gain to a point where you can hear the bass sort of coming from the sub and then turn down a notch but again experimenting is your friend
 

ChaosFlower

Novice Member
The Gemini II comes with a neurtalink cable that connects to the speaker terminals on your amp and to the high gain connection on the back of the sub. For music only this is the recommended way to run it (although experimentation is advised for every user). From what most people say on this forum, set the high gain to a point where you can hear the bass sort of coming from the sub and then turn down a notch but again experimenting is your friend

Thank you.. our main speakers not that disimilar so I could ask.. did you find a bit more oomph from the Gemini? The sub works well with your floorstanders and adds a bit more thump? I really don't know what to expect. My system is well loved... I just thought.. bk.. british made.. well regarded.. maybe a bit more thump would be nice.
 

luiscardoso88

Active Member
Hi. New member, though I am sure over the years I have read stuff on here.

Anyway, I was looking at the Gemini 2 and I found this thread.. 10 years this thread has been going!!

After 3 decades of owning hi-fi I have decided maybe I'd like to experiment with a sub. for my small living room 12ft by 10ft. My set up in that room is Arcam Alpha 10 amp, Mission M74 floorstanding speakers.. I have a 50in plasma also, and I like decent sound for movies, but primarily I am a 2 channel music guy.. well soon to be 2 channels and a sub... movies and music I prefer simple.. I just want the sub for a bit more thump. I will not be adding more speakers.

My speakers are aggressively toed in about 40 degrees along the longest wall and so fire across the narrowest length of the room.. which after much messing seemed to work best.

Questions.. do I use the low level or high level inputs? My amp has preout and power in phonos that are not connected (no bridge necessary). If high level do I put the high level neutrik cable on SP1 or SP2? If I put it on SP2 doees that mean I can disconnect the sub when not needed by switching off SP2? Is it correct you should turn the sub off before you turn the amp off? Will connecting that piggy back neutrik cable to SP1 or SP2 degrade my sound in anyway or cause stress to the amp i.e. effect impedance?

Am I right in thinking the Gemini has a toroidal supply and is class A/B?

Am I right in thinking that metal plate with the knobs and display on etc likely doubles as a heatsink? Obviously I have noticed higher models in the range have additional finned heatsinking attached..

Anyone look inside? What eletrolytic caps do BK use? I found a hazy picture of someone disassembling a gemini and it looks like they did or do use Samwha for the main filter caps.. which is good.. I'd prefer to see Japanese Rubycon, Nichicon, Panasonic.. but the Arcam Alphas used Aerovox, Rubycon, Taicon, Samwha.. and the South Korean Samwha appear to have very good longevity... I just don't trust Chinese electrolytics. Not yet anyway.

What kind of settings am I likely to probably settle with?

Thank you

You’re right: the Gemini II uses a toroidal power supply and is good old class AB. The big caps are those green and yellow Samwha you’ve mentioned.

BK seems to think that an exterior heatsink is not needed for this 150w amplifier but I would disagree, as it can get quite hot if pushed a bit.

Since this subwoofer uses a sealed housing, it is fast enough to keep up with music but doesn’t go very low.

It helped with my Quad Z1s but these are fairly bass light and have a 6” inch woofer, only.

Try to get the subwoofer in the corner of the room and play with the phase control. It should have enough shove in your room.
 

ChaosFlower

Novice Member
You’re right: the Gemini II uses a toroidal power supply and is good old class AB. The big caps are those green and yellow Samwha you’ve mentioned.

BK seems to think that an exterior heatsink is not needed for this 150w amplifier but I would disagree, as it can get quite hot if pushed a bit.

Since this subwoofer uses a sealed housing, it is fast enough to keep up with music but doesn’t go very low.

It helped with my Quad Z1s but these are fairly bass light and have a 6” inch woofer, only.

Try to get the subwoofer in the corner of the room and play with the phase control. It should have enough shove in your room.

My Missions have two 6.3in drivers and an inch soft dome tweeter. I expect I will put a heatsink on the Gemini plate using double sided heatsink tape. I have 12in 5v USB fans sucking air out of the vents on my elderly Arcam and other amps. A tad autistic? Maybe. I like looking after stuff. The cooler electronics are the happier they are.
 
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