Hello from the Netherlands

**jhk** · **10-17-07, 02:52 PM**

Hi there,

after reading some good threads i decided to join, hoping to find some more info about DIY subwoofers.

Currently owns: Harman Kardon AVR-435 KEF Q5, Q6 and wharfedale valdus 400 (could not buy the KEF Q1s and still had these). Subwoofers DIY two 140 liter bass reflex with 15 inch Beyma's.

Interested in: building a smaller sub with better response.

Bye

**Sonnie** · **10-17-07, 03:37 PM**

Hi Jaap and welcome to the Shack!

I was wondering if I'd ever run across anyone that has used Beyma's. One of our members, Rodny, works at a car audio shop and they were selling those for the car. I was amazed at the size of the magnet, but according to them, the car they listened to with Beyma's all the way around was very nice.

Look forward to having you around...

**jhk** · **10-17-07, 03:57 PM**

Beyma's are sold mostly for PA purposes a friend of mine who owns a small acoustics consultancy company uses them for all his PA sets.

I actually bougnt mine at a music shop (the one that sells guitars, keyboards and PA installations) they pretty 'tight' and punchy but the ones i own a more suited for low/ mid in stead of subwoofer use. They are quite sensitive at 97 db 1w/1m and have a respectible 35 Hz Fs but need some space with vas of 275 liter.

The qts is 0.32, power handling is 250W Rms.

BL is 18.9

I've built the subwoofers based on an old patent with the reflex end opening in front of the speaker. This should ensure the coherent phase of the system and should be benificial to dispersion. All of this said considering this is a subwoofer dispersion is not really the first concern and phase only as far as shifting phase and increasing group delay below tuning freq.

Nice to be around, hoping to learn a lot!

Greetz Jaap

**tweeksound** · **10-17-07, 08:59 PM**

welcome jhk.

Where did you learn DIY Sub design?

**jhk** · **10-18-07, 03:27 AM**

I'm a long time audio enthousiast and went to a technical college (more computer hardware related) so it's mostly self study reading various books and articles around the net. I'm not an audio specialist but do know electronics and acoustics to an acceptable level. Designs i'm interested in have gone from horn (LARGE) to TL (large), Karlson (dubious), JB or BJ (the one with the slit in front of the woofer for loading) back to bass reflex and sealed.

Only recently i've gained to possibility to really do something (before i was student and thus poor) therefore I have mostly book knowledge and an ear for nice/ good music, but not a lot of practical experience.

I've bought myself the behringer ecm 8000 and an edirol ua-25 to make some measurements and build some TL experiments.

I'm currently making the time to rebuild one of my beyma subwoofers (this work thing really reduces your free time) but at the same time considering selling them and starting over with new woofers.

Hoping to have answered your question

Greetz Jaap.

**tonyvdb** · **10-18-07, 10:04 AM**

Hello Jhk, Welcome to the Shack.
Its good to see someone from the country that my parents immigrated from. I love the Netherlands its a beautiful place. I spent 4 weeks there 15 years ago and will not forget it.
Enjoy your stay.

**thewire** · **10-18-07, 01:25 PM**

Welcome jhk. There is lots of great advise & info on here. My grandfather was from holland. One of my life goals is to visit my family there someday.

**nova** · **10-22-07, 02:13 PM**

Welcome to the Shack,.... lot's a folks in the DIY sub forums to share knowledge with.

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