Speaker Improvement Project

[mrb3]

Howdy everyone ! Welcome to my speaker improvement project.


The story

Maybe two or three years ago, I have laid my hands on four Boston Acoustics CR95 tower speakers (MSRP $550 a pair) that I found at $80 for the lot, and took this rare opportunity to compare those to my very nice Wharfedale 9.1 speakers (MSRP $350).

Long story short... Tough the Bostons had better bass (probably due to a bigger bass driver) I couldn't hear a radical difference between the two sets and as the Wharfedale took less space (and were already sounding impressively good for bookshelf speakers), I simply kept those in service.

But now that we moved to a new house with a larger livingroom, I'm tempted to put those Bostons to use... but the fact is four tower speakers simply steal too much living space... and this isn't helped by bass ports in the rear which makes speaker placement tricky as they can't be standing too near the wall.

Also, after much readings, it seems that the Bostons (though well rated speakers) have been built with compromises. The cabinets lacks dampening materials, the bass ports are relatively cheap and, most important, the crossovers could be of better quality.

And finaly, with time, we found that 2 way speakers had a tendency to muddy the sound when playing heavy music as the mid-range/bass driver become jam-packed with signals to reproduce (well, at least, that's the case with the Wharfedales). So, we are tempted to move up the ladder to 3-way speakers.


The Project

Convert four 2-way Boston Acoustics CR95 tower speakers into two 3-way tower speakers.


The Objectives

• Use less living space
• Improve the crossovers
• Improve the dampening
• Displace or eliminate the bass ports
• Sound as good or better than the original (especialy when listening to heavy music)
• Improve the look
• Have fun


The Budget

+/- $300


The Beasts

Boston Acoustics CR95
Power: 125 Watts
Construction: 2-Way
Frequency Response: 44 Hz - 20 000 kHz
Sensitivity: 90 db
Impedance: 8 ohm
Woofer Size: 7"
Tweeter Size: 1"
Crossover: 2500 Hz


Future Team Mates

Source: Pioneer SX-1280 (Restored)
Subwoofer: Mirage Omni S10


The Picture

 

[dnewma04]

For 300, add a subwoofer and call it a day.

 

[Squidward]

"Moving up the ladder" does not immediately imply adding more drivers. There are many three way systems that are bested by a quality two way implementation.

 

[mrb3]

For 300, add a subwoofer and call it a day.

I already have a subwoofer (Mirage Omni S10).

"Moving up the ladder" does not immediately imply adding more drivers. There are many three way systems that are bested by a quality two way implementation.

You're absolutely right ! But I do not want to buy an additional pair of speakers. Also, buying a new set wouldn't be as much fun as completing this project.

I'll post my preliminary plans soon.

 

[borus]

mrb3
Remove the boston tweeters. Isobaricly load the boston woofers. Lower the Wharfedales down into the space where the boston tweeters were. Use the now empty towers for extra bracing and flanges. Mass load the boston towers relocating the ports to the bottom. Use spikes for spacing. Cross the Isobaric woofers for a range from 80-350Hz 6db per then cross to the Wharfedales leaving their crossover as is. Or something else completely.

Borus

 

[RayW]

Also, after much readings, it seems that the Bostons (though well rated speakers) have been built with compromises. The cabinets lacks dampening materials, the bass ports are relatively cheap and, most important, the crossovers could be of better quality.

If those are the complaints you have about these speakers then I would suggest addressing those directly instead of trying to redesign them. If they lack damping in the cabinet, add some. Usually for a ported design you just want to line the walls with something to absorb backwave midrange from the woofer, you don't want to stuff it full. Ports being cheap will have no bearing on the sound. They don't do anything but hold air. If the location bothers you then move them to the front, but don't change them.

Crossover quality is too often associated with the number of components. The truth is the right crossover is the right crossover, no matter how many components. If you feel like replacing capacitors with better ones, that may help the sound. Replacing anything else probably won't affect the sound unless you start changing the wire gauge of inductors.

And finaly, with time, we found that 2 way speakers had a tendency to muddy the sound when playing heavy music as the mid-range/bass driver become jam-packed with signals to reproduce (well, at least, that's the case with the Wharfedales). So, we are tempted to move up the ladder to 3-way speakers.

I hope you meant that these particular 2-way speakers have a tendency to muddy the sound. I've heard plenty of 2-ways that could get stupid loud playing heavy music and not sound muddy. I would suggest adding some damping inside and making sure they are very stable before trying to redesign. If they're sitting on carpet then good spikes through the carpet to the floor can make a world of difference.

The bottom line is that you're contemplating taking drivers from the system they were designed for and forcing them into a role for which they're not suited. If a 3-way is your goal then you would be much better off selling the Bostons and using that money + your $300 and starting from scratch.

Ray

note to Dave: I'm much better rested.

 

[hypertone]

If a 3-way is your goal then you would be much better off selling the Bostons and using that money + your $300 and starting from scratch.

+1 :yes:

 

[HypnoToad]

Most speaker manufacturers today are making cheaper products.

Look at JBL you can by them for less than $100 each, they are nothing like the JBL of old though. And Boston Acoustics are the same.

Sell the Bostons and look around for a used quality pair of 3 way speakers, speakers don't generally wear out. The older ones can be susceptible to foam rot but even that's easily fixed.