LSi7's Refurb'ed and Upgraded, w/ pictures

geoff727

Hello all,

This is a project I just finished up, bringing a pair of LSi7's back to life. I assume LSi's can be considered vintage now, since the LSIM's are out (and I like the Vintage Speaker forum, anyway). This was a project I completed for my Dad, who had been subtley hinting to me for a couple years that he wanted some speakers in a gloss finish.

I bought the 7's off ebay; all 4 drivers were inop., and the cabinets had incurred some age. Here are what the speakers looked like when I bought them.

This pair was made before they started doing these in lacquer. The black finish is a plastic laminate, and it's easy to see how it's wrapped around the enclosure before the veneered "cheeks" were applied.

geoff727

The cheeks on these were held on with double-sided tape. This is somewhat interesting- in the 2003 Stereophile review of the LSi7's....

http://www.stereophile.com/standloudspeakers/795/index.html

....it states, "Two "cheeks" are attached to the enclosure's side panels to provide further damping". On this particular pair, I'm slightly dubious about that, given that they were attached with rubbery tape. However, I'm sure it's probably true of later models where the cheeks are glued on.

These are the enclosures being stripped and cleaned. It's easy to see the 'rectangle' of tape where the cheeks were attached.

geoff727

I decided to permanently attach the cheeks, and gain the value of the 'extra damping' referred to in the Stereophile review, along with the fact that I wanted one consistent finish across the entire speaker.

So, the cheeks were rigidly glued on, everything was filled, sanded, and shaped, and maple veneer was applied to the entire enclosure surface. First veneering step is in the 3rd photo. I also applied 2 layers of veneer to each driver's cut-out. You can see this in the left-hand speaker in the first photo. I did this to anticipate the thickness of the new finish, to keep the driver faceplates flush-mounted. In the second photo, everything is veneered and I'm just getting all the cutouts and final shaping and sanding in order.

geoff727

I decided to keep the general look of the LSi's, which I always liked. So, I made the center sections black. The cheeks I wanted to be red, so these had to be dyed. Here's the first speaker with the black center sections. Getting all those lines on the edge of the black perfectly straight on a now-smooth surface going around a corner and across edges...was no easy task!:rolleyes:

geoff727

Most of the rest of the enclosure work involved dyeing the cheeks red, and then the long process of applying the lacquer finish over the top of the whole thing. Here's some in-process photos.

geoff727

After the finish was done, the ports and rear port flare got re-installed, the grill tab female ends were put back in, and I applied some 3/4" Sonic Barrier to 4 different places inside the enclosure. Also, I installed inserts to accommodate 4 spikes on the bottoms of the enclosures, and also applied vinyl to the bottoms so they can be used without the spikes, without incurring any damage to the finish.

geoff727

On to the crossovers...

I wanted to use some excellent components in these. So, I opted for Sonicaps, Mills resistors, and AlphaCore foil inductors. Obvioulsy, these components incur a big size penalty over the original components, and this can be an issue in dealing with enclosure size. In a big enclosure, it may not matter, but in one this size, the percentage of size change can add up rapidly. So, if not careful, I could raise the F3 of the alignment, and end up with a peaking bass response not originally designed in the speaker.

Also, the mid-bass inductor is heavy. So strong mounting is paramount for long-term durability. And, things are in really close quarters, so I needed to keep inductors (including the mid-bass driver's voice coil) all mounted 90 degrees with respect to one another.

Here are the crossover parts, and the mounting boards I cut to mount everything on.

geoff727

And everybody's favorite part, the built-up crossovers...

chumlie

Damn nice work !

geoff727

Two close-up's of the inductor cradles...

Obviously, I incurred an internal volume loss with these. But, I did get an internal volume gain by going to a different binding post plate, one which isn't recessed into the speaker like the originals. Part of minimizing the loss was to make as many cutouts on the boards as I could and still retain structural integrity.

geoff727

And here's where it got really interesting. There's only one way those new components were going inside these small cabinets- straight up and down. And now you can see why the inductor cradles are so important here; they hold the big inductors firm and comply with 90-degree mounting with respect to the other inductors, the mid-bass driver's voice coil...and even the tweeter's voice coil.

The boards are attached inside in 3 places. One on the enclosure brace, and two with metal screws which run through to the binding post plate on the back of the enclosure (illustrated in the last picture). You can probably see the purpose for the notches in the sides of the top of the cradle....so I can shoot epoxy back in there to attach the upper part of the board to the enclosure brace. Looking back at the underside of the crossovers, you can see 2 small, shaped standoffs where the cradle meets the enclosure brace, right between the vertical white vinyl nuts and bolts; these assure the correct spacing and fit, because the inductor still 'pokes out' of the back of the cradle a little bit.

Notice, the inductor cradle almost touches the the big port tube (picture 3). And the bottom of the boards goes right up to the Sonic Barrier on the bottom of the enclosure....without putting so much as a dimple in it (picture 2). In other words, there's no room to spare, and planning these boards to piece together like this was a logistical challenge.

And now you can see another reason for all the cutouts. The boards are nearly as wide as the inside of the enclosure with the Sonic Barrier in it. I didn't want any airflow restriction occurring behind the boards, hence the cutouts.

geoff727

I did flying leads on the tweeters on these. I decided to use all soldered connections...no quick-disconnects. So, I decided to attach the tweeters and just work through the woofer holes to solder up all the proper wires. So, I attached the leads to the tweeters.

Once the drivers and binding post plates were attached (which solidified the crossovers in place) and everything was done, a quick impedance and phase measurement of both speakers confirmed that all was well. In this case, the Stereophile review measurement made by JA in 2003 served as a nice confirmation that I had hooked things up the same way.

Interestingly, in the Stereophile review, Fig. 1, a notch is visible in the impedance trace at about 800Hz. This is borne out by the cabinet resonance shown in the next figure. In my measurement, things changed slightly. The notch, now much less prominent, is also a bit lower in frequency. Is this due to more robust side panel mounting? Or just a difference in measuring equipment? Who knows.

geoff727

And finally, all done. Here you can see the vinyl and spikes on the bottom. New binding post plates which regain an inductor's worth of internal volume. Brand new grille cloth. Brand new drivers from Polk (thanks, Helen). The original serial number stickers on the binding post plates. And re-finished "Power Ports". Hope you all enjoy!

Geoff

leroyjr1

As usual very nice work.

chumlie

I bet you Dad really loves you. Beautiful work.

geoff727

geoff727 wrote: »

Interestingly, in the Stereophile review, Fig. 1, a notch is visible in the impedance trace at about 800Hz. This is borne out by the cabinet resonance shown in the next figure. In my measurement, things changed slightly. The notch, now much less prominent, is also a bit lower in frequency.

I just read through this again. JA's measurements actually said that the resonant spike in Fig. 2 was measured at 656Hz, not 800Hz like my quick glance suggested. Interestingly, 650Hz is right about where my graph shows the minor deviation in the impedance plot.

geoff727

Rick88 wrote: »

Wow, those are stunning!! I've never owned any LSi's and have been thinking about getting a pair of 7's to try, and you are making me want to even more...

I've only put about 10 minutes of music through them, one at a time. But, I was actually really enjoying listening to each one by itself! A couple weeks ago I decided to spring for a pair of LSi9's from Polk Direct on ebay. Like I really needed them, but what the heck, I like them!

halo71

Wow those are beautiful! Amazing transformation!

Braddles

Mate that is first class workmanship!

I envy people like you with the skill and patience to achieve what you have.

Looking forward to your thoughts on how they sound later.

Well done.

EndersShadow

Those look gorgeous! If a pair like that ever came up for purchase I would make a way to own em

drumminman

Really nice work, Geoff. On par with that which you did on that pair of RTA 12C's!

Mike Reeter

Beautiful work. I like the new binding post plates. You and your father should be very proud of your accomplishments.

Joe08867

Nice job, you do very nice work. I hope they sound as good as they look.

vstarkwell

I've marveled at your work before when you redid a pair of Monitor 5B's. Great job and you did your dad right. To quote the great Jeff Spicoli "Awesome! Totally Awesome!
.
Are you a wood worker by profession or is this just a hobby you've learned? I'd be really interested to find out how you became this proficient.

Toolfan66

This goes down as one of the best rebuilds around here in a long time!!!

What I like about it best?? Outside the stellar workmanship is they are not SDA's!!!

Fantastic, Beautiful work!!! Now I want to do the same hope you don't mind if I copy this?? ;-)



5 stars.....

rooftop59

dude those are AWESOME! I actually have a very similar pair that I got on ebay for dirt cheap (all the drivers work however) and I was thinking of just removing the sides and cleaning them up. Now you have inspired me. Blast you!!!

TNHNDYMAN

Your work and attention to detail is first rate. I would imagine Matthew Polk would be proud to have those in his listening room. You may want to offer your services to upstart speaker companies or at the least offer upgrade services for others. Your skills would command a premium that I'm sure enough would be willing to pay for.

Drenis

Gorgeous... they look stunning. I'm digging the red too.

Oldfatdogs

You always do such nice work,I'm interested in what dye you used I am making a set of stands out of maple and would like to put a cherry tint on them.Would you mind sharing what dye you used and where you got it?Thanks Dan

audiocr381ve

I want to sock you for being so good.

geoff727

Rick88 wrote: »

....how much are the LSi9's going for on Polk Direct?

About $550, for the "manufacturer refurbished" pair, which I can't distinguish from brand new. $365 is an awesome price for a new pair of 7's.