The new Elac speakers are quite the buzz, and they were a real hit at RMAF. They appeared to be a solid performer in the lower ranges of the cost spectrum. And they performed much better than other speakers in their price range and then some. At RMAF the Elac room sounded good enough to embarrass a lot of rooms with MUCH more costly speakers. So quite a few people began asking me how far these little speakers can be taken with some internal upgrades. I had enough people ask me about these that I felt it worth looking into. I even called up Andrew Jones and chatted with him about it.
Then I had a customer send me a pair of the B6 model still in the unopened box.
The first thing to do was to set them up and for testing and measuring to see where they were. They measured about as expected based on what I heard from the larger floor standing model at RMAF. Typically various problems and issues tend to stand out like a sore thumb to me. I hear them immediately and can't get past them. The larger ones playing at RMAF had no glaring problems other than the cabinet walls buzzing along with each bass note. Other than that they were smooth and balanced. They didn't standing out in any one way. They just sounded real good (too good) and very balanced for their price point.
Okay, all set up for measuring and here we go....
Here is the on axis response. This was the best response I got out of the two of them (the pair). This was without the grill.
They are real smooth up to about 2.5kHz. These will be pretty easy to listen to. The top end is pretty rolled off though. That will effect the imaging and spacial ques up there in the top octave. Still, overall this is real good. This is without the grill.
There was also good consistency with the pair. Here is the response curve of each speaker.
And here is the effect of the grill. With the grill it makes the blue line.
And here is the spectral decay. This is really the most telling of all measurements if you want to know how something will sound. And the spectral decay of the B6 looks really good. It decays very quickly and stores very little energy. There is a little excess ring in the 3kHz to 6kHz range but not bad at all. This was actually a little woofer cone break up. The crossover pushes it down about 20db. That's not great, but this is much better than a lot of speakers I have tested.
The horizontal off axis looks real good. These are taken on axis and then at 10,20, 30, and 40 degrees off axis.
The vertical off axis looks good too. There is just a little bit of a dipped area that forms in the crossover region as height increases, but that is not bad at all either. These are taken at 1 meter and each additional measure is made moving up four inches.
Next up is the impedance curve. Here we see a couple of issues. The impedance levels from the woofer to the tweeter are a bit of a mis-match. The levels are unusually higher on the tweeter end compared to the woofer. Some amplifiers will react differently to the different loads. For instance would you use the 8 ohm or 16 ohm taps on your tube amp? I think most customers aren't going to be driving them with high end tube amps though.
There were also a couple of resonate peaks in the 23Hz range and the 55Hz range. These are being caused by internal standing waves in the box. These can also excite the cabinet walls adding to the low frequency buzz of thin unbraced panels.
Next up was to remove the beauty rings that are covering the driver mounting. This is a little tricky to take off if you don't know how to do it. I finally figured it out. You have to reach in around the woofer edge and get it to pop up a little. Then slid in a flat head screw driver and twist it carefully to raise up each of the push in tabs. Do the woofer area first then you can move up to the area around the tweeter. Here is the front side.
And here is the back side.
And here is the speaker with it removed.
And here is the new response curve (light blue) without the beauty rings.
So if you want to improve the response just remove the grills and beauty rings.
Next was to have a look at the crossover. It is not bad for this price point. I see a lot worse.
I hate seeing sand caste resistors, but for this price point it is what I expected. All poly caps though. The inductor on the tweeter network is an air core, but the woofer network used a very thin gauge iron core inductor.
Mounting the network externally allowed me to measure the drivers independently. So I took a look at the tweeter curve.
Here is the tweeters response with and without the beauty ring. The blue line is without the beauty ring.
Also the top end was pretty rolled off. So I by-passed the inline resistor with a .47uF Sonicap. The light blue line shows the lifted top end.
This brought the top end up and made it much smoother overall.
Now here is the response of the speaker and individual drivers with the beauty rings off and the by-pass cap across the tweeters resistor. Looking pretty good now. The actual crossover point is at 2.5kHz rather than the advertised 3kHz point.
The by-pass of the inline resistor used on the tweeter will definitely have to be part of a budget upgrade.
Also, with the drivers out we can see the issues with the cabinets. There was very little damping material internally. And the unattenuated standing waves were causing the resonances seen in the impedance curves.
The front baffle is 3/4" thick, but the rest of the cabinet only has 1/2" thick unbraced panels. And it is the soft Chinese type of MDF that you can dig into with your finger nail. So lining the cabinet with No Rez will be a big upgrade. It will tighten up the bass response and clean up the panel resonances and the internal standing wave issues. This will clean the sound up considerably from the bass response up into the vocal region.
And here's a bonus tweak. Take some of the left over No Rez and cut it in small strips. Then peal the foam layer off of it so that you just have the damper only. Now apply those to the back side of the stamped steel woofer frame. This will keep the frame from ringing.
So I am going to offer what I call the level 1 B6 upgrade. This will include a sheet of No Rez. It will include a .47uF Gen. 2 Sonicap for lifting the top octave. It will include a 1.5uF Sonicap to replace the poly cap that's on the board. This will improve detail and clarity in the upper ranges. And it will include a 20 ohm Mills resistor. This will further improve clarity over the stock sand cast resistor and lift the range that the tweeter covers by about 1/2 of a db. This will help balance out the response. The crossover upgrades are easy add on's to the stock crossover board that the average Joe can do himself. The cost for all the parts, the sheet of No Rez, instructions, and support is $76. plus shipping.
Here is some illustrations for you guys to show how easy the Level 1 Mod really is.
You have to un-solder the tweeter cap and pull it off the board. It's the small yellow one that is a 1.5uF value. One side is easy to get to. Un-solder it first. Then use a box cutting knife or an exact-o knife to cut through a little of the adhesive holding it down. Put it up and stand it up on its end and then you can get the other side un-soldered pretty easily.
Next, un-solder the the leads on the 22 ohm resistor and just fold them to the side so that they are out of the way. Don't bother pulling it off the board. It is glued on too well and it doesn't hurt anything to just leave it there.
Now take a very small drill bit and drill out the solder holes so that you have a fresh hole to slide the new parts in through.
Now twist the new .47uF Sonicap onto the new Mills 20 ohm resister as seen here. Solder them together and solder them into the spot where the old resistor was mounted.
Then flip it over and solder in the new 1.5uF Sonicap into the same spot as the old 1.5uF cap. Be careful not to let your soldering gun touch the small inductor next to it.
It should now look like this:
Lastly, run a little line of hot glue across the parts to help hold them all down.
This will lift the tweeter level just a little bit, it will lift up the rolled off top end, and improve clarity all across the tweeters range.
It is a pretty simple upgrade for the average hobbyist. If you are not a hobbyist and aren't interested in un-soldering and soldering on new parts then send me your crossover and I'll put the new parts on for you and send them back ready to go. $10 plus the shipping cost is the least I can charge for dong this. It really doesn't cover my time very well, but I am making a little on the parts cost.
The rest of this mod is installing the No Rez in the cabinets. This will do away with the cabinet resonances, tighten up the bass response, and clean up the vocal region.
Again the level 1 mod is only $76.
