Pensil series loudspeakers for small listening room - Page 6

Knight Rider · 8th March 2011, 10:45 AM

Hello!

Could you please give me any instructions how to fill the inside of the Pensil 12 cabinet with Polyester fiber? I have a feeling that my cabinets are maybe too full of this material. The cabinets are maybe not breathing as they should. Should I use folded plate material?

planet10 · 8th March 2011, 09:45 PM

Loose polyfluff -- well teased and as uniform as possible -- is what you want. Fill the entire cabinet (you can leave as much as the bottom 1/3rd of the box free of fluff if that is what it takes to get the bottom you need, very often only to the top of the vent is done for cosmetic purposes.

Every room and taste (and qualities of the polyfluff used) will have a bit different need to achieve optimum... why the back is removeable. On P7 we started with the specifies amount and ended up taking out about a third of it.

dave

zman01 · 9th March 2011, 12:41 PM

Knight Rider,

Pls get your stuffing amount right and give us some more listening impressions.

Knight Rider · 10th March 2011, 05:56 AM

Quote:

Originally Posted by zman01

Knight Rider,

Pls get your stuffing amount right and give us some more listening impressions.

Hello!

Maybe about 500 grams (or a little bit less) is the optimum amount of stuffing for me. Then I'm happy with the lower bass region. But unfortunately I'm still not happy with the overall sound. I'm not sure what is wrong, maybe the lower mid range area is too thin and the midrange area is boosting too much. This is a little bit strange for me, because I haven't had this kind of problems with earlier loudspeakers.

Knight Rider · 14th March 2011, 08:24 AM

Hello!

I did couple of measurements yesterday, to check if there are any problems in frequency responce. According to those measurements there are no big issues. What you think about those small "hills" (blue graph) around 500-600 hz and >1 khz? Are they shouting to my ears?

planet10 · 14th March 2011, 10:52 AM

I wouldn't worry

dave

norman bates · 14th March 2011, 12:29 PM

sitting a little off axis should help if the highs are too much........

Box stuffing is tricky, you can change it 3 or 4 times before you decide to forget about it.

Looks like you can get them closer to a wall, add some baffle step, try a much wider box, or play with eq. I getting to be a believer in wide baffles (2' or 61cm).

Norman

Scottmoose · 14th March 2011, 01:52 PM

Hmm. No real step-loss indicated in those plots, which show a pretty flat (it's not half bad for an FR based speaker) response to ~5KHz where the A12 begins to peak up. They wouldn't really benefit a great deal from a wider baffle in this sense as driver & box are largely self-correcting, although in terms of wavelaunch & edge diffraction it will obviously be different to a narrower baffle cabinet.

The A12 was designed to be listened to slightly off-axis, as is also indicated in the above plots, along with those from Mark & the Japanese magazine measures, so sitting off axis (about 10 degrees) as noted by Norman is a good move.

Knight Rider · 14th March 2011, 03:06 PM

About port tuning: is it normal behaviour that it boosts also ~200 hz? The graph may also show some diffraction from Alpair element, so it's maybe not absolutely correct.

Scottmoose · 04:16 PM

Yes, it's doing what it's designed to do.

8th March 2011, 09:45 PM	#52
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 5	Loose polyfluff -- well teased and as uniform as possible -- is what you want. Fill the entire cabinet (you can leave as much as the bottom 1/3rd of the box free of fluff if that is what it takes to get the bottom you need, very often only to the top of the vent is done for cosmetic purposes. Every room and taste (and qualities of the polyfluff used) will have a bit different need to achieve optimum... why the back is removeable. On P7 we started with the specifies amount and ended up taking out about a third of it. dave __________________ community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

14th March 2011, 10:52 AM	#56
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 5	I wouldn't worry dave __________________ community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

14th March 2011, 04:05 PM	#60
Scottmoose diyAudio Member Join Date: Mar 2005 Location: UK	Yes, it's doing what it's designed to do. Last edited by Scottmoose; 14th March 2011 at 04:16 PM.

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8th March 2011, 10:45 AM	#51
Knight Rider diyAudio Member Join Date: Dec 2010	Hello! Could you please give me any instructions how to fill the inside of the Pensil 12 cabinet with Polyester fiber? I have a feeling that my cabinets are maybe too full of this material. The cabinets are maybe not breathing as they should. Should I use folded plate material?

9th March 2011, 12:41 PM	#53
zman01 diyAudio Member Join Date: Feb 2011 Location: Dhaka	Knight Rider, Pls get your stuffing amount right and give us some more listening impressions.

14th March 2011, 12:29 PM	#57
norman bates diyAudio Member Join Date: Nov 2003 Location: iowa	sitting a little off axis should help if the highs are too much........ Box stuffing is tricky, you can change it 3 or 4 times before you decide to forget about it. Looks like you can get them closer to a wall, add some baffle step, try a much wider box, or play with eq. I getting to be a believer in wide baffles (2' or 61cm). Norman

14th March 2011, 01:52 PM	#58
Scottmoose diyAudio Member Join Date: Mar 2005 Location: UK	Hmm. No real step-loss indicated in those plots, which show a pretty flat (it's not half bad for an FR based speaker) response to ~5KHz where the A12 begins to peak up. They wouldn't really benefit a great deal from a wider baffle in this sense as driver & box are largely self-correcting, although in terms of wavelaunch & edge diffraction it will obviously be different to a narrower baffle cabinet. The A12 was designed to be listened to slightly off-axis, as is also indicated in the above plots, along with those from Mark & the Japanese magazine measures, so sitting off axis (about 10 degrees) as noted by Norman is a good move.

14th March 2011, 03:06 PM	#59
Knight Rider diyAudio Member Join Date: Dec 2010	About port tuning: is it normal behaviour that it boosts also ~200 hz? The graph may also show some diffraction from Alpair element, so it's maybe not absolutely correct.

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