Monolith iiixb

[Robert D]

The panels came from Martin Logan The Woofers were sourced from Parts Express ( Goldwood GW-12PC-4 12" Heavy Duty Woofer 4 Ohm ) The original woofers Eminence made for them are not manufactured anymore. They were not that good to begin with and were the designs weak link. The crossovers are external to the speakers and came with them. There were a couple of options depending on your setup at the time. More than likely your woofers can be re-coned if they are damaged. Just contact ML tech support. They will help you out.

I think the woofers are fine. Just wondering if mine would be like your's and benefit from a higher quality woofer. I dont know anything about what is in there now and if it is a weak link like your's. My Prodigies seemed to have weak base but I figured out that AUdyssey had it turned way down I think, because my panels werent putting out much. Once I get the new panels in I should get more bass too I think. I use my depth i sub for most of the bass, but could probably use more "mid bass".

The woofers in there now seem to be made of metal, im guessing aluminum?

 

[JonFo]

[oops, wrong thread]

 

[JonFo]

I purchased the Goldwood GW-12PC-4 12" Heavy Duty Woofer 4 Ohm

First, congrats on getting the speakers fully operational.

When retaining the factory passive, having a closer match on woofer impedance is important. The Goldwood also has higher efficiency, so it is putting out more volume than the Peerless as well.
Other specs look good, but it has a higher moving mass, and thus a bit higher THD at the higher frequencies, but nothing major.
So this is a nice find for those wanting to retain their passive crossovers.

I removed and shorted the connection point of one coil to lower the inductance to 5 Mh. This will move the crossover point of the woofer slightly higher frequency.

Yep, the Monolith performs much better if the woofer to panel XO is higher than the stock 250Hz.
It would be nice if you could document the XO mods a bit more for others who might want to do the same.

 

[modavid]

I think the woofers are fine. Just wondering if mine would be like your's and benefit from a higher quality woofer. I dont know anything about what is in there now and if it is a weak link like your's. My Prodigies seemed to have weak base but I figured out that AUdyssey had it turned way down I think, because my panels werent putting out much. Once I get the new panels in I should get more bass too I think. I use my depth i sub for most of the bass, but could probably use more "mid bass".

The woofers in there now seem to be made of metal, im guessing aluminum?

Yes i would be sceptical if it is not paper. From research and guidance from knowledgeable folks on this thread it is recommended to try and stay as close to the original specs of the OEM Eminence woofers. You need to remember the panels react very fast and a chunky woofer designed for subs would not play well with the panels. If you are using the passive x-over shorting one of the coils will increase the crossover point to a higher frequency and you will hear more mid base. The Goldwood woofer does a great job operating in this frequency band. I will upload the crossover schematic

 

[modavid]

Instructions for crossover modification.

Remove the Cover from the crossover unit. There will be three 5mH coils mounted under the PCB. Two of these inductors connected in series are used in the Low Pass circuit and are connected via screw terminals on the PCB on the side nearest to the 470 uF capacitor. Disconnect one of these coils from the circuit by removing its leads from the screw terminals. Insert a jumper wire between the terminals where the coil was connected to restore the connection. Sorry I did not photodocument the procedure when I had everything opened up.
The XSim schematic file and the crossover images can be downloaded HERE. I did not include the low pass attenuation switch when I transposed the original schematic. The Presence switch will "tame" the high end projection somewhat by modifying the curve. This adjustment was much more noticeable to me when my panels were replaced. The new panels are much brighter sounding and this subtle attenuation setting is perfect for speakers in a smaller room.