Impedance Bass Reflex - check up Beyma 12B100R - Page 3

Audio Elite · 17th October 2012, 03:42 PM

Yes you will be supprised, they can play there are good spl as well. I know one guy that used 2 of them in a sub using the O Audio plate amp to drive it! Very musical and quick.

jzagaja · 17th October 2012, 03:44 PM

2 cu. ft. for 12BR70 with good results vs. 5 cu. ft. for 12B100R is huge difference

jzagaja · 17th October 2012, 07:35 PM

Impedance with and without notch.

Dissi · 17th October 2012, 10:20 PM

Proper bass reflex function can seriously be affected by two factors:
1. Interaction with some types of passive crossover filters
2. Standing waves in tube-like enclosures
Sorry Jzagaja, as long as you do not reveal any information on that, we are fishing in the dark.

jzagaja · 17th October 2012, 10:32 PM

Tell me what would you like to know

Dissi · 17th October 2012, 11:00 PM

Best would be a diagram of the crossover (woofer section only) and a sketch/picture of the cabinet, but a description in words will do as well. I'm very surprised to see the left impedance peak rising due to the notch. Do you have an enclosure with a large dimension (1m or more)?

jzagaja · 18th October 2012, 05:48 AM

Take a look.

Dissi · 18th October 2012, 10:35 AM

The enclosure looks nice. It's thin and long and is actually a tapered quarter wave tube (TQWT). For that reason the results are different from a classic bass reflex box and you do not have enough kickbass. The calculation of a TQWT is very difficult, I can not do that.

VaNarn · 18th October 2012, 08:22 PM

It's a commercial design to sell on looks rather than giving optimal sound.I would completely fill it up with Tontine or other suitable stuffing,if that has not been done already.The notch filter is what it was said to be and not impedance correction as I had assumed.It is possibly there to alleviate a strong column resonance and my thought is that this type of problem is better dealt with by elimination at its' source rather than a secondary 'cure'.

jzagaja · 18th October 2012, 08:25 PM

The idea behind Mummy was to have universal case so that anyone can try waveguide with his/her favorite woofer and driver. With 12BR70 it works great. With 12B100R a bit shy.

17th October 2012, 03:44 PM	#22
jzagaja diyAudio Member Join Date: Jun 2004 Location: Szczecin	2 cu. ft. for 12BR70 with good results vs. 5 cu. ft. for 12B100R is huge difference __________________ Visit us at http://www.horns.pl/ The SEOS™ Project http://www.avsforum.com/t/1291022/he...-rallying-here

17th October 2012, 10:32 PM	#25
jzagaja diyAudio Member Join Date: Jun 2004 Location: Szczecin	Tell me what would you like to know __________________ Visit us at http://www.horns.pl/ The SEOS™ Project http://www.avsforum.com/t/1291022/he...-rallying-here

18th October 2012, 08:25 PM	#30
jzagaja diyAudio Member Join Date: Jun 2004 Location: Szczecin	The idea behind Mummy was to have universal case so that anyone can try waveguide with his/her favorite woofer and driver. With 12BR70 it works great. With 12B100R a bit shy. __________________ Visit us at http://www.horns.pl/ The SEOS™ Project http://www.avsforum.com/t/1291022/he...-rallying-here

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17th October 2012, 03:42 PM	#21
Audio Elite diyAudio Member Join Date: Sep 2007	Yes you will be supprised, they can play there are good spl as well. I know one guy that used 2 of them in a sub using the O Audio plate amp to drive it! Very musical and quick.

17th October 2012, 10:20 PM	#24
Dissi diyAudio Member Join Date: Sep 2012	Proper bass reflex function can seriously be affected by two factors: 1. Interaction with some types of passive crossover filters 2. Standing waves in tube-like enclosures Sorry Jzagaja, as long as you do not reveal any information on that, we are fishing in the dark.

17th October 2012, 11:00 PM	#26
Dissi diyAudio Member Join Date: Sep 2012	Best would be a diagram of the crossover (woofer section only) and a sketch/picture of the cabinet, but a description in words will do as well. I'm very surprised to see the left impedance peak rising due to the notch. Do you have an enclosure with a large dimension (1m or more)?

18th October 2012, 10:35 AM	#28
Dissi diyAudio Member Join Date: Sep 2012	The enclosure looks nice. It's thin and long and is actually a tapered quarter wave tube (TQWT). For that reason the results are different from a classic bass reflex box and you do not have enough kickbass. The calculation of a TQWT is very difficult, I can not do that.

18th October 2012, 08:22 PM	#29
VaNarn diyAudio Member Join Date: Dec 2010 Location: Ivanhoe	It's a commercial design to sell on looks rather than giving optimal sound.I would completely fill it up with Tontine or other suitable stuffing,if that has not been done already.The notch filter is what it was said to be and not impedance correction as I had assumed.It is possibly there to alleviate a strong column resonance and my thought is that this type of problem is better dealt with by elimination at its' source rather than a secondary 'cure'.

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