# Bass management by sub for Kef Picoforte set-up



## ndurantz (Aug 10, 2008)

Hi All,

I snatched up a Picoforte iPod docking system for $100 on close out and wanted to add some to the low end. The specs say that the Picoforte goes down to 80 Hz, but we all know that is a stretch for speakers so small.

I have two subs available. A Yamaha YST-FSW100 slim sub that has no freq. cross-over management and specs at 30 Hz to 200 Hz. I also have an Energy ESW-8 sub that has freq. cross-over management and specks at 33 Hz to 150 Hz.

I have hooked up both and noticed that I have to turn the volume level up on the sub pretty close to max to get decent response. I am assuming that is due to the weak power supply in the picoforte, but would like someone to confirm that for me.

Also, I am wondering if I really need the cross-over management. On a system that small, with source material just being HQ mp3/aac tracks from my iPod, is it really that important to control the cross-over? I guess what I am really asking is how would the picoforte manage the bass on the Yamaha sub - would the sub takeover at 200 Hz, would the picoforte manage it to another freq., or would they just overlap from 80ish to 200 Hz? A chance to educate a budding enthusiast :bigsmile:

Knowing what happens with the low-end with the picoforte/Yamaha set-up will help me decide which one to go with. I am still within the return period for the Energy, so trying to decide if it is worth keeping.

Thanks!


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## Mike P. (Apr 6, 2007)

It sounds like the Picoforte has a low output voltage feeding the sub. Try a RCA Y adapter to input both the L and R sub inputs on the Energy amp. Another option is to connect the L and R speaker outputs of the Picoforte to the speaker level inputs on the Energy sub amp.


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## ndurantz (Aug 10, 2008)

Mike P. said:


> It sounds like the Picoforte has a low output voltage feeding the sub. Try a RCA Y adapter to input both the L and R sub inputs on the Energy amp. Another option is to connect the L and R speaker outputs of the Picoforte to the speaker level inputs on the Energy sub amp.


I did plug into both L/R inputs, but not sure the mini-plug was plugged all the way in. The back of the picoforte is is pretty crowded. I may have to get a mini-stereo extender to be sure. The monoprice mini-stereo to RCA cable I have has a really thick jacket on it.


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## Mike P. (Apr 6, 2007)

You can try the speaker level inputs and see if that makes a difference.


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## ndurantz (Aug 10, 2008)

Mike P. said:


> You can try the speaker level inputs and see if that makes a difference.


Maybe I am missing the obvious, but if I do that, how do I hook up my left/right speakers? There is only one set of speaker outputs on the back of the pictoforte.

Any thoughts on how the picoforte may manage the low frequencies with the yamaha sub? (See initial post)


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## ndurantz (Aug 10, 2008)

Update: Got a mini plug extender to all me use of the L & R RCA cable from monoprice. It has worked well in my set-up with the Energy sub. However, I still have to turn the sub up to almost full volume to get it to produce much sound. It doesn't sound bad (quite nice, actually), I would just like the low-end to have more presence in the overall mix.

What do you all think of adding some type of additional amp for the sub using the line out on the dock from the Picoforte? I wouldn't want to spend a ton as I have only invested around $200 total in this set-up, as it would seem like overkill. Thoughts? Suggestions?


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## lsiberian (Mar 24, 2009)

You are definitely not getting enough gain. But that's not surprising for a small $100 mp3 dock.

I'd at the very least corner load the sub. Since it could be a placement issue.


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## ndurantz (Aug 10, 2008)

lsiberian said:


> You are definitely not getting enough gain. But that's not surprising for a small $100 mp3 dock.
> 
> I'd at the very least corner load the sub. Since it could be a placement issue.


Corner load - as in place in the corner of the room? Facing the wall or away from the wall? I should mention that it is a carpeted floor, so I am sure I am getting some absorbtion.

And while it probably has no bearing on the issue at hand, the dock and speakers are Kef and had an original retail of $400 - quality stuff, but pretty small on the power.


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## Jon Liu (May 21, 2007)

You can put the sub in the corner, facing whichever direction shouldn't matter too much although you can play with the direction to see if you can hear any audible differences. This will help with some boundary gain to compensate as lsiberian was alluding to.


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## ndurantz (Aug 10, 2008)

Sounds like a good option. I will give it a shot and let you all know. Thanks for the input!!


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## ndurantz (Aug 10, 2008)

Messed around with the placement a bit, but still pretty subdued. I am starting to feel ok about it, though as the sound is nice an balanced - just lacking that punch, but I think I was expecting too much from that little iPod dock/amp.

Which brings me to another question - is running the energy sub off of a low power amp like that detrimental to the sub? Is there a potential for damage to the sub?


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## Jon Liu (May 21, 2007)

I think so. You run the chance of having massive distortion and clipping with an amp that is under powering your sub.


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## ndurantz (Aug 10, 2008)

Jon Liu said:


> I think so. You run the chance of having massive distortion and clipping with an amp that is under powering your sub.


I haven't heard any distortion up to this point. Here are the specs for both the Picoforte and the Energy sub:

PicoForte - http://www.google.com/products/catalog?q=picoforte&rls=com.microsoft:*&oe=UTF-8&um=1&ie=UTF-8&cid=11114767512746561807&ei=cw8HS7PTAYLIlAfvzrCFBA&sa=X&oi=product_catalog_result&ct=result&resnum=1&ved=0CAoQ8wIwAA&os=tech-specs

Energy Sub - http://www.energy-speakers.com/na-en/products/esw-8-specifications/

Don't know if that helps confirm your suspicions or not. Also, if you have time, maybe tell me what I am looking for to avoid a "mis-match" between these two pieces?

Thanks!


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## ndurantz (Aug 10, 2008)

Ok. I haven't had anyone respond to my question above, so I am asking again......pretty please. Also, I did find a line level booster. Would that help the situation some? Here is the link to the specs on the line level booster - http://www.phonopreamps.com/TC-780ipp.html

Thanks for any insight someone can provide!!


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## selden (Nov 15, 2009)

Clipping doesn't hurt subs, but can fry tweeters. The high frequencies caused by clipping won't get past its crossover.

The crossover should help with matching the sub to the picoforte's speakers. The results might not be audiophile quality, since the crossover's high-frequency fall-off probably won't exactly match the PicoForte's speakers' low frequency fall-off.

The line amp you found does look like it should help.


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## ndurantz (Aug 10, 2008)

selden said:


> Clipping doesn't hurt subs, but can fry tweeters. The high frequencies caused by clipping won't get past its crossover.
> 
> The crossover should help with matching the sub to the picoforte's speakers. The results might not be audiophile quality, since the crossover's high-frequency fall-off probably won't exactly match the PicoForte's speakers' low frequency fall-off.
> 
> The line amp you found does look like it should help.


That is reassuring. Thank you! 

I have the crossover set around 110 after messing around with it and seems to be about the best balance, but I still feel l am missing something. If I go higher, the lower vocal range gets pushed to the sub and doesn't sound very good. If I go lower, it seems the picoforte's are being asked to do more than they can.

I suppose even with $50 spent on the line level booster, the whole system would still be around $250, which really isn't bad at all for the sound/flexibility I am getting.

Anyone have other thoughts?


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