# New small two-way design



## carlmart (Nov 21, 2009)

I'm considering a new project to replace my computer speakers. 

These should be high quality, as I use them for editing audio. 

What I'm thinking of is small (5-liter) vented box with two SB drivers:

Tweeter: SB SB29RDCN-C000-4 Neo Magnet, Ring Dome

Mid-woofer: SB SB12NRX2504 4" woofer

I think they might be a good mating, as they are both 4 ohm types and have approximately similar sensitivity.

Has anyone worked on something like it, in size or application?


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## Mike P. (Apr 6, 2007)

Have you modeled the SB12NRX2504 4" woofer in 5 liters to see how it would perform?


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## carlmart (Nov 21, 2009)

Mike P. said:


> Have you modeled the SB12NRX2504 4" woofer in 5 liters to see how it would perform?


Yes, in Bassbox 6 Pro. Both for sealed and vented box.


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## Brewski (Jan 8, 2010)

carlmart said:


> I'm considering a new project to replace my computer speakers.
> 
> These should be high quality, as I use them for editing audio.
> 
> ...


I'd listen to a set of speakers with the SB29RDCN before deciding if you want to go with it or not. I used them in a 2.5 way and always felt they were missing something from the top end. I'm comparing the SB29 neo vs. speakers I've made with the vifa DX25 and vifa BC25SG15. In each of the three speakers I liked the vifa tweeters more. I've heard good things about the vifa neo line so that's what I'm considering using for a tweeter in my center channel.

Take it easy
Jay


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## fusseli (May 1, 2007)

Sounds like you're off to a good start. What will you be powering them with?


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## Theresa (Aug 23, 2010)

Everything I've read about SB drivers says they are very good for the price, including John Kruttke, aka Zaph Audio. They should be as they are designed by former engineers from ScanSpeak.


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## carlmart (Nov 21, 2009)

fusseli said:


> Sounds like you're off to a good start. What will you be powering them with?


Sorry for my delay to get back. 

I should be powering these speakers with a DIY amp called MyRefC, which has many followers in the DIYForum. 

It's based around the LM3886 chip, but it's much more sophisticated design than what most people are doing with it. 

I'm getting a kit in eBay, and I will replace some parts for better ones. 

Yes, I also think the SB speakers are promising, and Zaph's tests and comments are encouraging. The SB tweeter is even more expensive than the Vifa XT, but you can cross it quite lower. Which is usually the mark of a good tweeter. None of the those Vifa mentioned can be crossed too low.


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## Brewski (Jan 8, 2010)

carlmart said:


> Sorry for my delay to get back.
> 
> I should be powering these speakers with a DIY amp called MyRefC, which has many followers in the DIYForum.
> 
> ...


Best of luck with the project. How low are you going to cross them? I originally was trying to cross the SB29RDCN at a 1750 LR4 slope and the tweeter sounded good the majority of the time but did show signs of straining on some female vocals at DIY NE (Claire Lynch Wabash Cannonball). Once they were relaxed to LR4 2200 slope they no longer showed signs of straining in the original ruinations. 

As for the vifa tweeters the DX25 can't cross as low due to it's large impedance spike but vifa BC25SG15 has been crossed as low as 1800 LR4 slope without impedance compensation and 1700 4th order bessel slope with compensation in different designs.

Take it easy
Jay


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## carlmart (Nov 21, 2009)

First of all I would never use a cross order greater than LR3. There are major phase issues if you go higher, I think, and I would rather use active crossing/amping if I had to. 

Second I would like to keep the mid-woof working as much as possible, so I will probably try crossing around 2K/2K5. No impedance compensation of any kind, if possible, for any of them.


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## Brewski (Jan 8, 2010)

We might be talking apples and oranges so figured I'd ask are you refering to electrical or accoustic order in terms of not exceeding LR3?

For example the levitations are 2nd electrical yielding a 4th order bessel accoustic slope on the tweeter and 2nd order elctrical yielding thrid order accoustic slopes on the woofer.

Take it easy
Jay


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