[PSItech]

Interesting video.
I'm a bit hesitant when it comes to frequency responses measured from a Magnepan speaker though. The room and location of the speaker and microphone do a have a lot of impact on the accuracy of the measurement. For example, the bass-hump Danny measures, I don't perceive while listening...
Anyway, if I only could hear the improvement before purchasing the upgrade, that would be great...but I guess I have to wait until a number of LRS owners upgraded their speakers and objectively report on it.
I'll keep an eye on https://www.gr-research.com/store/c24/Magnepan_Upgrades.html.

Paul

[Saturn94]

Interesting video.
I'm a bit hesitant when it comes to frequency responses measured from a Magnepan speaker though. The room and location of the speaker and microphone do a have a lot of impact on the accuracy of the measurement. For example, the bass-hump Danny measures, I don't perceive while listening...
Anyway, if I only could hear the improvement before purchasing the upgrade, that would be great...but I guess I have to wait until a number of LRS owners upgraded their speakers and objectively report on it.
I'll keep an eye on https://www.gr-research.com/store/c24/Magnepan_Upgrades.html.

Paul

Have you done any updates to your LRS yet?

[PSItech]

Have you done any updates to your LRS yet?

No, I did not - been busy with way too much other things...

Paul

[NIGHTFALL1970]

I want to know if Danny’s upgrade on Magnepan 1.7s would make them sound better than a pair of 1.7is.

[trebejo]

Hmmm... maybe they have some suggestions here?

https://www.audioasylum.com/cgi/etv.mpl?forum=mug

[PSItech]

Teaser! Before...

After...


Just did the first speaker. Today/tomorrow the other one.

Paul

[NIGHTFALL1970]

Please report back on how it sounds.👍

[PSItech]

After listening for a few hours, I would say the sound improvement is...subtle.
Best way to describe it is that bass around the 100Hz area has lessened a bit and some low frequency extension has been gained.
The other thing I noticed is when playing loud is that the bass seems cleaner/dryer and better discernible.

Rest to say, this is all very subjective. So don't expect major improvements - as said it's subtle.

Next messages will show photo's of the disassembly and later I will share the crossover schematic and DATS V3 impedance/phase measurements.

Paul

[PSItech]

The disassembly starts:



Remove the stands and screws. Remove the screws of the entry plate:



Use a scriber and carefully insert it between wooden strip and cloth until the strip comes loose. The strip is held in place with headless nails. When the strip comes loose you will see the nail stick in the cabinet. Pull the nail out with pliers. Then I used a tie-wrap to keep the strip bent out.















Now remove 2 rows of staples:







Shove the cloth up so that it exposes the crossover parts:



Turn over the LRS so you see this:



Remove the tape and cardboard piece carefully so that you can reuse them afterwards:





Turn the LRS over again so that you can access the crossover. Desolder the coil and wires and clean up the solder lugs. I also removed the brown wire and soldered the green wire directly to the connector plate. Place the coil and use tie-wraps to mount it. Resolder all the wires and coils. Notice that I got rid of the faston connectors and soldered the wires directly to the connector.











Now it's time to reassemble. Place tape and card board and start stapling. Mount connector plate and feet.





The wooden strips can be tapped back in their groove and stay put without using nails.

Done! Enjoy listening your LRS's.

Next message will be the crossover schematic and DATS V3 impedance/phase measurements.

Paul

[PSItech]

This is the Magnepan LRS crossover:



Below are 2 impedance/phase plots [stock and after the coil mod]:





Identical as you can see.

With respect to the new coils: I purchased 2pcs https://www.mundorf.com/audio/en/shop/coils/air_coils/mcoil_l/MCoil-L140-AirCore/?card=5106. These have a value of 1.0mH. So, using the DATS V3 tool, I unwinded about 14-15 turns of each coil such that I ended up with 0.86mH /0.27 ohm coils.
The original stock coils measured to be 0.88mH / 0.26 ohm.

Here is a picture of the original coil:



In case you're interested, here are the impedance/phase plots of the individual LRS drivers.

Low frequency driver:


High frequency driver:


Paul

[HAL]

You can make very good on axis measurements of the LRS speakers at 1m since they are small.

You would need to use the time gated function of the measurement system to remove the first room reflection and on in the time waveform.  Programs like REW and CLIO have this as a capability. 

In the case of the LRS, you might put it on a box to lift it off the floor and put it in the middle of the room to extend time to the first reflection.

I get close to Danny's frequency response using my CLIO Pocket and my 1.7's with the original crossover, but it is longer, so moved the mic back to see the entire diaphragm.

The idea is that F=1/T.  So the lowest frequency you can use is based on how long a first reflection free time you can measure.  If you get 5mS time to the first reflection, the lowest frequency you can use is 200Hz.  Everything below that frequency is unusable data.