Subwoofer advice

[wilsmusic]

Hi all. First post in ages!

I have a BK subwoofer on the way to compliment my LS50's.

There will be times when the system needs to play very loud to fill a big room. Hence buying the sub.

Demo'd my kit in this room the other day and I had the Roksan K2 BT turned up all the way to 4/5 pm. Normally never gets passed 11!

so my question is about the difference between hi and low level inputs on the BK and whether either makes a difference to the amount of work the amp needs to do? Specifically does using the pre outs on the amp to connect to the sub make any difference to workload compared to wiring the BK to the speaker posts of the amp?

i am no electrical expert so advice appreciated!

Thanks.

 

[Andrewjvt]

Hi all. First post in ages!

I have a BK subwoofer on the way to compliment my LS50's. 

There will be times when the system needs to play very loud to fill a big room. Hence buying the sub. 

Demo'd my kit in this room the other day and I had the Roksan K2 BT turned up all the way to 4/5 pm. Normally never gets passed 11!

so my question is about the difference between hi and low level inputs on the BK and whether either makes a difference to the amount of work the amp needs to do?  Specifically does using the pre outs on the amp to connect to the sub make any difference to workload compared to wiring the BK to the speaker posts of the amp?

i am no electrical expert so advice appreciated!

Thanks. 

First if you play your kandy that high on the volume knob you will certainly blow the kefs

 

[nopiano]

If you wire an amplified sub to preouts, you have no need to worry about the work the amplifier itself does. In the context you mean it, the work is done by the power amp part of your amp, which is driving your LS50s only.

 

[wilsmusic]

yes. I was worried about that too. Realise Kandy is rated 140w.

What do you think is the max the ls50's can take?

thanks

 

[Pedro]

yes. I was worried about that too. Realise Kandy is rated 140w. 

What do you think is the max the ls50's can take?

thanks

 

 

It's in their specs: 100W. I'm guessing it's continuous power.
You'll be fine with a more powerful amp, unless you push it to insane levels.
Edit: 11 o clock must be really loud. Many amps deliver full power with the volume knob around 12 o clock.

 

[nopiano]

You should the hear speakers sounding nasty long before you damage them.

 

[wilsmusic]

It was those little woofers that were working overtime the harder I pushed them. They lost control of the base once and I turned it down sharpish. I figure if I let the sub take over from 70/80 hz down that will take away a lot of the load?

ls50's are hard to drive little buggers 11 o'clock with those is 9 o'clock wit every othe speaker I have owned.

 

[insider9]

4-5pm on Kandy... What distance were standing from the speakers or were you in a different room? Or simply was this a party?

I'm sure short term they could withhold more than 100W which you just did but the voice coils will be boiling hot after a sustained period and would eventually fail. If you did that with older speakers you'd probably be starting a different thread.

 

[davedotco]

Amplifier power and speaker ratings are actually quite complex. Music varies enormously in the king of power it uses so there really are no hard and fast rules.

You can overheat and destroy your speakers by using too much continuous power or you can damage them by clipping the amp on peaks, even though the continuous power is much less. You need to use some common sense.

I do not believe that any of the BK subs have high pass filters to limit the bass to the main speakers, you kefs will be driven full range as normal however you connect the sub.

 

[davidf]

Most amps are kickout out maximum around the 12 o'clock point, but like some amps, the Kandy doesn't.

 

[Alberich]

Most amps are kickout out maximum around the 12 o'clock point, but like some amps, the Kandy doesn't.

Primare is another one.
My old i22 didn't really get going until 50 (out of 100).
Edit - may even have been 80 max volume if my memory serves me correctly

 

[insider9]

Most amps are kickout out maximum around the 12 o'clock point, but like some amps, the Kandy doesn't.

Primare is another one.
My old i22 didn't really get going until 50 (out of 100).
Edit - may even have been 80 max volume if my memory serves me correctly

I believe it was 80 or 79 even but not 100 for sure

The volume pot on Primare amps is a joy to use.

 

[nopiano]

Most amps are kickout out maximum around the 12 o'clock point, but like some amps, the Kandy doesn't.

Primare is another one. My old i22 didn't really get going until 50 (out of 100). Edit - may even have been 80 max volume if my memory serves me correctly

I believe it was 80 or 79 even but not 100 for sure

The volume pot on Primare amps is a joy to use.

Yep, 50 is about right on mine! But then it's properly designed.

 

[Alberich]

Most amps are kickout out maximum around the 12 o'clock point, but like some amps, the Kandy doesn't.

Primare is another one. My old i22 didn't really get going until 50 (out of 100). Edit - may even have been 80 max volume if my memory serves me correctly

I believe it was 80 or 79 even but not 100 for sure

The volume pot on Primare amps is a joy to use.

Yep, 50 is about right on mine!   But then it's properly designed.  

Never sounded shouty either even when cranked into the 60's. Smooth as a baby's arse.

 

[insider9]

Most amps are kickout out maximum around the 12 o'clock point, but like some amps, the Kandy doesn't.

Primare is another one. My old i22 didn't really get going until 50 (out of 100). Edit - may even have been 80 max volume if my memory serves me correctly

I believe it was 80 or 79 even but not 100 for sure

The volume pot on Primare amps is a joy to use.

Yep, 50 is about right on mine!   But then it's properly designed.  

Never sounded shouty either even when cranked into the 60's. Smooth as a baby's arse.

I remember setting mine to max 55. Very useful feature especially if you consume alcohol when listening.

 

[wilsmusic]

Hmmm. Ok. I always assumed that is what setting the crosssover frequency did?

 

[davedotco]

Hmmm. Ok. I always assumed that is what setting the crosssover frequency did?

Not in this case.

The crossover simply determines the frequency that the sub rolls off, the main speakers continue to be driven full range. There are some subs that offer the option of filtering out low frequncies to the main speakers, usually below about 80hz, but they are quite rare in the hi-fi world.

If you are looking for something to take the load off the Kefs at high levels, this will not do it, you need a sub with a hi-pass filter.

 

[Samd]

Hmmm. Ok. I always assumed that is what setting the crosssover frequency did?

Not in this case.

The crossover simply determines the frequency that the sub rolls off, the main speakers continue to be driven full range. There are some subs that offer the option of filtering out low frequncies to the main speakers, usually below about 80hz, but they are quite rare in the hi-fi world.

If you are looking for something to take the load off the Kefs at high levels, this will not do it, you need a sub with a hi-pass filter.

Why don't stereo amps have a facility similar to AVRs where the main speakers can then reduce the load? Is it simply that most stereo users do not use subs?

 

[jonathanRD]

Hmmm. Ok. I always assumed that is what setting the crosssover frequency did?

Not in this case.

The crossover simply determines the frequency that the sub rolls off, the main speakers continue to be driven full range. There are some subs that offer the option of filtering out low frequncies to the main speakers, usually below about 80hz, but they are quite rare in the hi-fi world.

If you are looking for something to take the load off the Kefs at high levels, this will not do it, you need a sub with a hi-pass filter.

Why don't stereo amps have a facility similar to AVRs where the main speakers can then reduce the load? Is it simply that most stereo users do not use subs?

I would imagine that most stereo users wouldn't be looking to reduce the load.

 

[davedotco]

Hmmm. Ok. I always assumed that is what setting the crosssover frequency did?

Not in this case.

The crossover simply determines the frequency that the sub rolls off, the main speakers continue to be driven full range. There are some subs that offer the option of filtering out low frequncies to the main speakers, usually below about 80hz, but they are quite rare in the hi-fi world.

If you are looking for something to take the load off the Kefs at high levels, this will not do it, you need a sub with a hi-pass filter.

Why don't stereo amps have a facility similar to AVRs where the main speakers can then reduce the load? Is it simply that most stereo users do not use subs?

I would imagine that most stereo users wouldn't be looking to reduce the load.

For hi-fi use it is usually considered best practice to run the main speakers full range and let the sub extend the natural bass performance to lower frequencies.

Advocates of this technique suggest that this produces the most natural, musical results.

Though I agree totally with the above, it has been my experience that many sub users want a boombox type effect which is not what the better hi-fi subwoofers are designed to achieve,

 

[wilsmusic]

Thanks for everyone's comments so far. Looking at kef ls50's specs it says maximum loudness is 106db. So as long as i stay benaeath that i should be ok?

Unfortunately there is no eqivalent spec for the Kandy that i can see.

Buying a home cinema amp to control bass output is not an option.

So instead i can simply download a sound metre app to my phone and check db output that way. I guess these apps are not the last word in accuracy so wont push it all the way 106db.

My problem is if this volume level doesnt fill the room then i am looking for new speakers!

 

[insider9]

Thanks for everyone's comments so far.  Looking at kef ls50's specs it says maximum loudness is 106db.  So as long as i stay benaeath that i should be ok?

Unfortunately there is no eqivalent spec for the Kandy that i can see.  

Buying a home cinema amp to control bass output is not an option.

So instead i can simply download a sound metre app to my phone and check db output that way.  I guess these apps are not the last word in accuracy so wont push it all the way 106db.  

My problem is if this volume level doesnt fill the room then i am looking for new speakers!  

It looks like you may be expecting too much from such a diminutive and not the most sensitive speaker.

It's not why people buy standmounts... volume and filling the room. That's where floorstanders come in.

 

[davedotco]

Thanks for everyone's comments so far. Looking at kef ls50's specs it says maximum loudness is 106db. So as long as i stay benaeath that i should be ok?

Unfortunately there is no eqivalent spec for the Kandy that i can see.

Buying a home cinema amp to control bass output is not an option.

So instead i can simply download a sound metre app to my phone and check db output that way. I guess these apps are not the last word in accuracy so wont push it all the way 106db.

My problem is if this volume level doesnt fill the room then i am looking for new speakers!

There are so many factors involved here that it is very difficult to determin safe and reliable levels for equipment of this kind, normally it is down to using your ears and a bit of common sense.

According to the figures, the LS50 require a little over 200watts peak to produce their maximum 106Db output. This is close to the capabilities of the Kandy and the continuous output with music with a reasonable dynamic range of say, 12Db, will be about 50 watts.

If the LS50s 100 watt power rating is for continuous power, this should be safe, though personally I would be surprised if the LS50s can handle this kind of power for any length of time.

If you play music that is heavily compressed and bass heavy, the continuous power requirements will rise markedly, probably with disastrous consequences.

To be frank, if you want to be able to play loud, you have the wrong speakers, good as the LS50s are, they are not really designed for the kind of use you are thinking off.

 

[insider9]

Hmmm. Ok. I always assumed that is what setting the crosssover frequency did?

Not in this case.

The crossover simply determines the frequency that the sub rolls off, the main speakers continue to be driven full range. There are some subs that offer the option of filtering out low frequncies to the main speakers, usually below about 80hz, but they are quite rare in the hi-fi world.

If you are looking for something to take the load off the Kefs at high levels, this will not do it, you need a sub with a hi-pass filter.

Why don't stereo amps have a facility similar to AVRs where the main speakers can then reduce the load?  Is it simply that most stereo users do not use subs?

I would imagine that most stereo users wouldn't be looking to reduce the load. 

For hi-fi use it is usually considered best practice to run the main speakers full range and let the sub extend the natural bass performance to lower frequencies.

Advocates of this technique suggest that this produces the most natural, musical results.

Though I agree totally with the above, it has been my experience that many sub users want a boombox type effect which is not what the better hi-fi subwoofers are designed to achieve,

Having tried both I can't see why. It's not only the bass that's affected. By crossing over to a sub higher than natural roll off of speakers there are significant advantages. Not just that but it's rally hard to implement a sub with inbuilt crossover because of phase issues.

Positioning of the sub that can be different to speakers and as a result helping to achieve flatter in room response.

Allowing speakers to reproduce midrange with more clarity. Big advantage for two way bookshelves. By crossing over a sub at say 120Hz midrange driver no longer had a burden of long strokes that are required to reproduce low frequencies. This clears up the mid range considerably.

Unfortunately it's difficult (near impossible) to do it by ear and equally so without an external crossover that allows time delay.

 

[davedotco]

Hmmm. Ok. I always assumed that is what setting the crosssover frequency did?

Not in this case.

The crossover simply determines the frequency that the sub rolls off, the main speakers continue to be driven full range. There are some subs that offer the option of filtering out low frequncies to the main speakers, usually below about 80hz, but they are quite rare in the hi-fi world.

If you are looking for something to take the load off the Kefs at high levels, this will not do it, you need a sub with a hi-pass filter.

Why don't stereo amps have a facility similar to AVRs where the main speakers can then reduce the load? Is it simply that most stereo users do not use subs?

I would imagine that most stereo users wouldn't be looking to reduce the load.

For hi-fi use it is usually considered best practice to run the main speakers full range and let the sub extend the natural bass performance to lower frequencies.

Advocates of this technique suggest that this produces the most natural, musical results.

Though I agree totally with the above, it has been my experience that many sub users want a boombox type effect which is not what the better hi-fi subwoofers are designed to achieve,

Having tried both I can't see why. It's not only the bass that's affected. By crossing over to a sub higher than natural roll off of speakers there are significant advantages. Not just that but it's rally hard to implement a sub with inbuilt crossover because of phase issues.

Positioning of the sub that can be different to speakers and as a result helping to achieve flatter in room response.

Allowing speakers to reproduce midrange with more clarity. Big advantage for two way bookshelves. By crossing over a sub at say 120Hz midrange driver no longer had a burden of long strokes that are required to reproduce low frequencies. This clears up the mid range considerably.

Unfortunately it's difficult (near impossible) to do it by ear and equally so without an external crossover that allows time delay.

I agree that this is a contentious issue, both approaches have merit and I can see how relieving the main speakers of deep bass may have benefits. With some speakers that really might help a lot.

However my experience suggests that the most natural results involve running the speakers full range, with the sub just augmenting the lowest frequencies though this is clearly only a subjective judgement.

If the aim is to increase the loudness capability of the system, as may be the case here, then filtering the main speakers is clearly a big advantage, whether it would be a sufficient boost to give the OP what he is looking for is another matter.