Centre speaker. Using Vifa MG18WK09-04?

NickZ · 4th December 2005, 05:32 PM

Okay I built my first speaker and I know I can handle the assembly part just fine. The idea that got this thing all started was a centre speaker and a subwoofer. So the next step is the centre speaker.

I was thinking

Vifa MG18WK09-04 [Two wired in series]

and a Seas 27TBFCG

Would this be a good match? From what little I understand crossover at 2k?

FWIW the L&R are a pair of PSB Alpha B.

Mark Techer · 5th December 2005, 07:15 AM

If you series the drivers, you lose efficiency.

I paralleled two VIFA P17SJ-00-08 drivers and used three XT25SC-30-04 also in parallel.

LR 2nd order crossover at just 1550hz and 6dB attenuation on the three tweeters and WOW!!!

The speaker in the photo is actually my right speaker, but I built three for Left, Centre and Right...

Mark

NickZ · 5th December 2005, 10:58 AM

If I parallel two 8ohm drivers then I end up with a 4 ohm load. I don't think the receiver is rated for a 4 ohm load. Or am I missing something?

Mark Techer · 6th December 2005, 01:16 AM

You'd be hard pressed to find a late model AVR that is rated 4 ohm stable, but it is OK...IMHO it their way of CYA

The reason AVRs are rated at a minimum of 6 ohms is to stop people connecting multiple loudspeakers in parallel. Two 8 is 4, but three 8s would be just 2.6, and that is where you run into trouble, and yet people try to do this...

I have been successfully running my 7.1 system (all diy, all 4 ohm using twin VIFA woofers) for coming on to three years now. In fact, although there is a setting for speakers under 8 ohm, the system actually sounds more dynamic using the 8 ohm setting when running these speakers. My AVR is a Pioneer VSX1011 (THX Select 7.1) and is rated at 130 WRMS in 8 ohms. It works very well...

Mark

NickZ · 6th December 2005, 04:45 PM

I'm gutless when it comes to stuff like this

I'd rather stay at 8 . I figure I may replace the speakers hooked up to the music system. If I do those will be 4 ohms. But that amp is rated for 4 so I'll feel okay.

Mark Techer · 6th December 2005, 10:07 PM

The very first set of speakers I ever built had the drivers in series as they were 4 ohm drivers (car audio) and you had to drive them hard to get any decent SPL. It was originally for a stereo pair, but as I was getting into surround sound, I decided that I should build a third speaker for the centre channel giving me three identical LCR speakers. I have never looked back from that concept and I still have these in a box to this day...

I then moved on to real hi-fi driver like Peerless and Vifa. I built a set of dipoles using two 6.5" Peerless and the 1" dome tweeter. The crossover was a off the shelf item intended for a 4 ohm load (again car gear). Not real sure if I should be driving a 4 ohm load at that time, I series some resisters after the crossover's negative terminal to raise the resistance. It worked OK, but the raise also changed (raised) the crossover frequency.

Then I re-thought LCRs and decided to use Vifa 5 1/4" 16 ohm drivers in parallel. It still gave me 8 ohms but ran more efficiently. Again I was still using off the shelf crossovers and then turned my attention to building crossovers for my speakers...

From there I tried two Vifa 6.5" 8 ohm drivers in parallel and have since stuck with that since. Naturally, I designed and built my own crossovers. I am unable to wind my own coils, so am forced to work with an Asian made import line of 18 gauge wire coils...

The most recent upgrade has been to implement the Vifa "ring" radiators and wow, they are pretty special...

Today I use a total of 17 (3 on each LCR and 2 on each surround) of the Vifa 1" ring radiator, and 14 of the Vifa 6.5" woofers (2 per speaker) plus two sets of Peerless XLS woofers/passive combos driven by a 350 watt plate amp. The project all came together really well and at a fraction of the cost of buying commercial product.

DIY rocks! Those that bag it do so simply because they have not yet succeeded...

Mark

NickZ · 7th December 2005, 02:46 AM

I'll be asking about a crossover later

I was at the local electronic surplus place and he had various parts but I didn't know exactly what to ask for. Looking at the Solens catalog there seems to be a wide range of prices. Oh well no real rush.

Mark Techer · 7th December 2005, 07:21 AM

Feel free to ask when you are ready. I am still learning and am willing to share my experiences with others

Mark

4th December 2005, 05:32 PM	#1
NickZ diyAudio Member Join Date: Jun 2005 Location: Toronto	Centre speaker. Using Vifa MG18WK09-04? Okay I built my first speaker and I know I can handle the assembly part just fine. The idea that got this thing all started was a centre speaker and a subwoofer. So the next step is the centre speaker. I was thinking Vifa MG18WK09-04 [Two wired in series] and a Seas 27TBFCG Would this be a good match? From what little I understand crossover at 2k? FWIW the L&R are a pair of PSB Alpha B.

6th December 2005, 01:16 AM	#4
Mark Techer diyAudio Member Join Date: Aug 2005	You'd be hard pressed to find a late model AVR that is rated 4 ohm stable, but it is OK...IMHO it their way of CYA The reason AVRs are rated at a minimum of 6 ohms is to stop people connecting multiple loudspeakers in parallel. Two 8 is 4, but three 8s would be just 2.6, and that is where you run into trouble, and yet people try to do this... I have been successfully running my 7.1 system (all diy, all 4 ohm using twin VIFA woofers) for coming on to three years now. In fact, although there is a setting for speakers under 8 ohm, the system actually sounds more dynamic using the 8 ohm setting when running these speakers. My AVR is a Pioneer VSX1011 (THX Select 7.1) and is rated at 130 WRMS in 8 ohms. It works very well... Mark __________________ CIH Explained

6th December 2005, 10:07 PM	#6
Mark Techer diyAudio Member Join Date: Aug 2005	A bit about my speaker projects... The very first set of speakers I ever built had the drivers in series as they were 4 ohm drivers (car audio) and you had to drive them hard to get any decent SPL. It was originally for a stereo pair, but as I was getting into surround sound, I decided that I should build a third speaker for the centre channel giving me three identical LCR speakers. I have never looked back from that concept and I still have these in a box to this day... I then moved on to real hi-fi driver like Peerless and Vifa. I built a set of dipoles using two 6.5" Peerless and the 1" dome tweeter. The crossover was a off the shelf item intended for a 4 ohm load (again car gear). Not real sure if I should be driving a 4 ohm load at that time, I series some resisters after the crossover's negative terminal to raise the resistance. It worked OK, but the raise also changed (raised) the crossover frequency. Then I re-thought LCRs and decided to use Vifa 5 1/4" 16 ohm drivers in parallel. It still gave me 8 ohms but ran more efficiently. Again I was still using off the shelf crossovers and then turned my attention to building crossovers for my speakers... From there I tried two Vifa 6.5" 8 ohm drivers in parallel and have since stuck with that since. Naturally, I designed and built my own crossovers. I am unable to wind my own coils, so am forced to work with an Asian made import line of 18 gauge wire coils... The most recent upgrade has been to implement the Vifa "ring" radiators and wow, they are pretty special... Today I use a total of 17 (3 on each LCR and 2 on each surround) of the Vifa 1" ring radiator, and 14 of the Vifa 6.5" woofers (2 per speaker) plus two sets of Peerless XLS woofers/passive combos driven by a 350 watt plate amp. The project all came together really well and at a fraction of the cost of buying commercial product. DIY rocks! Those that bag it do so simply because they have not yet succeeded... Mark __________________ CIH Explained

7th December 2005, 07:21 AM	#8
Mark Techer diyAudio Member Join Date: Aug 2005	Feel free to ask when you are ready. I am still learning and am willing to share my experiences with others Mark __________________ CIH Explained

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5th December 2005, 10:58 AM	#3
NickZ diyAudio Member Join Date: Jun 2005 Location: Toronto	If I parallel two 8ohm drivers then I end up with a 4 ohm load. I don't think the receiver is rated for a 4 ohm load. Or am I missing something?

6th December 2005, 04:45 PM	#5
NickZ diyAudio Member Join Date: Jun 2005 Location: Toronto	I'm gutless when it comes to stuff like this I'd rather stay at 8 . I figure I may replace the speakers hooked up to the music system. If I do those will be 4 ohms. But that amp is rated for 4 so I'll feel okay.

7th December 2005, 02:46 AM	#7
NickZ diyAudio Member Join Date: Jun 2005 Location: Toronto	I'll be asking about a crossover later I was at the local electronic surplus place and he had various parts but I didn't know exactly what to ask for. Looking at the Solens catalog there seems to be a wide range of prices. Oh well no real rush.

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