Optimus Pro LX-4 mods

Senn · 19th March 2005, 06:45 PM

I recently purchased a pair of these infamous monitors cheap - they're enroute via UPS - and wish to perform the basic mods published by Dick Olsher years ago (I've downloaded the pages). However, I was wondering if there exists a tutorial somewhere online that includes photos, me being a newbie to modding and all. Also, if anybody has gone even further with the mods - replacing the Kevlar woofer, for example, feel free to chime in. I'd like as much info as possible on mods to this speaker in addition to any after-mod suggestions for getting the best possible performance out of them. Thank you all.

TheSlimMan · 20th March 2005, 02:10 AM

What sort of x-o is on those? On the LX-5's, they originally came with a simple first order x-o on the woofers & tweeters. I now use a second order Butterworth low-pass on the woofer at 2,000Hz and a second order butterworth high-pass on the tweeters at 2,500Hz. Also some Polyfil stuffing and Dynamat sheets on the interior of the enclosure. These simple mods turned these into some VERY nice sounding speakers. Later, I'll probably build some real (wood) enclosures for 'em.

With those tweeters, distance from the rear wall becomes real important.

mac · 20th March 2005, 02:20 AM

I have a set of LX4's and they sound very good in stock form. The problem with the woofer is that it's run wide open w/o a choke. I wouldn’t recommend changing the woofer but would advise placing a small value choke in series with it. The single cap in series with the tweeter should be bypasses or replaced with a high quality metalized polypropylene. The cabinet trim can be removed with a router and this will reduce baffle diffraction. Btw, the tweeter in the LX4 is monopole, unlike the one in the LX5.

Senn · 20th March 2005, 02:25 PM

First of all, thank you Slim Man & Mac. I have posted on MANY forums this past week and your replies have been the only helpful ones.

Second, I am the definitive newbie, BRAND NEW to this hobby. The only time(s) I've dismantled speakers in the past was to have x-overs shipped out to somebody else for re-building. I have friends/relatives who are in electricity & electronics and carpentry, and they'll help me out for no more than a cup of coffee. BTW, I have NOT opened up these speakers, yet.

SLIM MAN - as far as I know, there is no traditional x-o in these speakers. There is a cap in line with the tweeter which will be replaced with a "Kimber Kap". I cannot use polyfil because the speaker is vented but will use damping sheets and, as Olsher's mods instruct, add a "square" of foam underneath the woofer. Olsher also suggests placing an air-core inductor in line with the woofer. I found a Jantzen 18awg model in the Parts Express catalog but I'm not sure I should buy it because 19-20awg is recommended (can't find one). Could you comment on the above and also elaborate on placement after your tweeter comment? Thanks!

MAC - Is an air-core inductor a valve choke? Do they do the same thing or is one better than the other? Did you replace the internal wiring and, if so, with what? Did you take photos of the project and, if so, could you please post them?

Thanks again, folks. Thank you for your suggestions and I thank you in advance for your continuing patience.

TheSlimMan · 20th March 2005, 03:38 PM

Senn, good choice on the Kimber Kap. About the 18ga. inductor, it close enough so it should be O.K. Actually, you can use polyfill, I've done so in my LX-5's. My theory is that it helps dampen the speaker back-wave and the woofer "thinks" it's in a slightly larger enclosure. I doesn't hurt a thing and it's easily reverseable if need be.

The Optimus center-channel that uses the same tweeter has a second order X-O on the woofer and tweeter. If you like, I can take a look and see what component values are in there.

BTW, could you post a link to those mods by Dick Olsher if you still have it?

Senn · 20th March 2005, 04:54 PM

Slim Man,

Try this:

http://www.blackdahlia.com/tipindex/Tip_3/tip_3.html

I hope the link works and I hope you find the info on the website helpful & interesting.

Yes, you can give me any/all relative info that you can think of. Please remember my "Newbie" status, though, and be gentle.

As far as using polyfil in a vented enclosure, I have read about doing so in the past - sometimes just "teasing" it out and other times really packing it in - and listening to the results of each. I'll have to try it after doing the other mods.

Thanks!

Senn · 23rd March 2005, 06:47 PM

Mac, et al:

Speakers arrived. After unpacking, noticed that one of the ribbon tweeters is slightly wrinkled - hardly "like new" as advertised. The other speakers tweeter is perfect.

The wrinkled tweeter wrinkles where it folds in - at the center of the tweeter - the rest of the ribbon is perfectly smooth and retains its softness. There are no holes, tears (except in my eyes), etc. Other than the wrinkling near the center folds all else looks great.

To the untrained onlooker, it appears as if the ribbon got wet somehow and wrinkled upon drying. I just don't know. Somebody I know with several pairs of speakers, some with ribbon tweeters, tells me that the ribbon material is very tough and the wrinkles should not have an effect on the sound. Somebody else suggested they may have been overdriven and the wrinkles signify melting. I hope that's not the case!!!

Anyway, I ran high frequency test tones from my CD player with the Optimus' hooked up to a Parasound amp. They sounded fine - both of them (I tested individually). I then played a few CD's (female singers) and they also sounded fine (I see what people mean about these ribbon tweeters being so airy & natural!).

Do you think the wrinkled tweeter ribbon is a non-issue? Of course, I wish they looked fine, but as long as they sound fine - that's the real issue, isn't it?

Thanks, again.

budwiser · 23rd March 2005, 08:07 PM

I have the LX-5's and one of my tweeters has the same condition. Not sure how this happened but I am the original owner of these speakers. They still sound good. I used mortite to dampen the cabinet and also put some strips on the back of the woofer. I have contemplated working on the xover components but am in the process of building some proac 2.5 clones.

Pete

Senn · 23rd March 2005, 09:21 PM

Bud...

Any idea how it happened?

Did you perform high frequency testing, one speaker at a time (with an SPL meter) to test whether the pair still sounded identical, like I did?

Thanks for the re-assuring post. I 'spose that the ribbon is just a part of the tweeter and, as a friend told me, the material is very tough and unless it's torn (or has holes in it) there shouldn't be any sonic difference.

budwiser · 23rd March 2005, 09:54 PM

No test where done, but I could do that. At one time I had the grills that cover the tweeter off and something could have happened then. I did'nt really notice it until weeks later when I was testing the results of the mortite appplication. I noticed thru the grill that the tweeter looked alittle odd compared to t he other. Took the top of and it was wrinkled alittle.

19th March 2005, 06:45 PM	#1
Senn diyAudio Member Join Date: Mar 2005 Location: Northeast U.S.	Optimus Pro LX-4 mods I recently purchased a pair of these infamous monitors cheap - they're enroute via UPS - and wish to perform the basic mods published by Dick Olsher years ago (I've downloaded the pages). However, I was wondering if there exists a tutorial somewhere online that includes photos, me being a newbie to modding and all. Also, if anybody has gone even further with the mods - replacing the Kevlar woofer, for example, feel free to chime in. I'd like as much info as possible on mods to this speaker in addition to any after-mod suggestions for getting the best possible performance out of them. Thank you all.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Optimus speakers	mikje	Multi-Way	2	3rd July 2009 01:00 AM
Realistic Optimus X-100 speakers	Trebla	Multi-Way	0	30th November 2006 12:05 PM
Realistic Optimus T-200	skanter	Multi-Way	15	3rd October 2006 08:26 PM
optimus pro-x88av crossover mod...	MyNameIsJake	Multi-Way	3	4th June 2006 08:40 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

20th March 2005, 02:10 AM	#2
TheSlimMan diyAudio Member Join Date: Mar 2003 Location: Baltimore	What sort of x-o is on those? On the LX-5's, they originally came with a simple first order x-o on the woofers & tweeters. I now use a second order Butterworth low-pass on the woofer at 2,000Hz and a second order butterworth high-pass on the tweeters at 2,500Hz. Also some Polyfil stuffing and Dynamat sheets on the interior of the enclosure. These simple mods turned these into some VERY nice sounding speakers. Later, I'll probably build some real (wood) enclosures for 'em. With those tweeters, distance from the rear wall becomes real important.

20th March 2005, 02:20 AM	#3
mac diyAudio Member Join Date: May 2003 Location: Puget Sound	I have a set of LX4's and they sound very good in stock form. The problem with the woofer is that it's run wide open w/o a choke. I wouldn’t recommend changing the woofer but would advise placing a small value choke in series with it. The single cap in series with the tweeter should be bypasses or replaced with a high quality metalized polypropylene. The cabinet trim can be removed with a router and this will reduce baffle diffraction. Btw, the tweeter in the LX4 is monopole, unlike the one in the LX5.

20th March 2005, 02:25 PM	#4
Senn diyAudio Member Join Date: Mar 2005 Location: Northeast U.S.	First of all, thank you Slim Man & Mac. I have posted on MANY forums this past week and your replies have been the only helpful ones. Second, I am the definitive newbie, BRAND NEW to this hobby. The only time(s) I've dismantled speakers in the past was to have x-overs shipped out to somebody else for re-building. I have friends/relatives who are in electricity & electronics and carpentry, and they'll help me out for no more than a cup of coffee. BTW, I have NOT opened up these speakers, yet. SLIM MAN - as far as I know, there is no traditional x-o in these speakers. There is a cap in line with the tweeter which will be replaced with a "Kimber Kap". I cannot use polyfil because the speaker is vented but will use damping sheets and, as Olsher's mods instruct, add a "square" of foam underneath the woofer. Olsher also suggests placing an air-core inductor in line with the woofer. I found a Jantzen 18awg model in the Parts Express catalog but I'm not sure I should buy it because 19-20awg is recommended (can't find one). Could you comment on the above and also elaborate on placement after your tweeter comment? Thanks! MAC - Is an air-core inductor a valve choke? Do they do the same thing or is one better than the other? Did you replace the internal wiring and, if so, with what? Did you take photos of the project and, if so, could you please post them? Thanks again, folks. Thank you for your suggestions and I thank you in advance for your continuing patience.

20th March 2005, 03:38 PM	#5
TheSlimMan diyAudio Member Join Date: Mar 2003 Location: Baltimore	Senn, good choice on the Kimber Kap. About the 18ga. inductor, it close enough so it should be O.K. Actually, you can use polyfill, I've done so in my LX-5's. My theory is that it helps dampen the speaker back-wave and the woofer "thinks" it's in a slightly larger enclosure. I doesn't hurt a thing and it's easily reverseable if need be. The Optimus center-channel that uses the same tweeter has a second order X-O on the woofer and tweeter. If you like, I can take a look and see what component values are in there. BTW, could you post a link to those mods by Dick Olsher if you still have it?

20th March 2005, 04:54 PM	#6
Senn diyAudio Member Join Date: Mar 2005 Location: Northeast U.S.	Slim Man, Try this: http://www.blackdahlia.com/tipindex/Tip_3/tip_3.html I hope the link works and I hope you find the info on the website helpful & interesting. Yes, you can give me any/all relative info that you can think of. Please remember my "Newbie" status, though, and be gentle. As far as using polyfil in a vented enclosure, I have read about doing so in the past - sometimes just "teasing" it out and other times really packing it in - and listening to the results of each. I'll have to try it after doing the other mods. Thanks!

23rd March 2005, 06:47 PM	#7
Senn diyAudio Member Join Date: Mar 2005 Location: Northeast U.S.	Mac, et al: Speakers arrived. After unpacking, noticed that one of the ribbon tweeters is slightly wrinkled - hardly "like new" as advertised. The other speakers tweeter is perfect. The wrinkled tweeter wrinkles where it folds in - at the center of the tweeter - the rest of the ribbon is perfectly smooth and retains its softness. There are no holes, tears (except in my eyes), etc. Other than the wrinkling near the center folds all else looks great. To the untrained onlooker, it appears as if the ribbon got wet somehow and wrinkled upon drying. I just don't know. Somebody I know with several pairs of speakers, some with ribbon tweeters, tells me that the ribbon material is very tough and the wrinkles should not have an effect on the sound. Somebody else suggested they may have been overdriven and the wrinkles signify melting. I hope that's not the case!!! Anyway, I ran high frequency test tones from my CD player with the Optimus' hooked up to a Parasound amp. They sounded fine - both of them (I tested individually). I then played a few CD's (female singers) and they also sounded fine (I see what people mean about these ribbon tweeters being so airy & natural!). Do you think the wrinkled tweeter ribbon is a non-issue? Of course, I wish they looked fine, but as long as they sound fine - that's the real issue, isn't it? Thanks, again.

23rd March 2005, 08:07 PM	#8
budwiser diyAudio Member Join Date: Jan 2004 Location: Greenwood, IN	I have the LX-5's and one of my tweeters has the same condition. Not sure how this happened but I am the original owner of these speakers. They still sound good. I used mortite to dampen the cabinet and also put some strips on the back of the woofer. I have contemplated working on the xover components but am in the process of building some proac 2.5 clones. Pete

23rd March 2005, 09:21 PM	#9
Senn diyAudio Member Join Date: Mar 2005 Location: Northeast U.S.	Bud... Any idea how it happened? Did you perform high frequency testing, one speaker at a time (with an SPL meter) to test whether the pair still sounded identical, like I did? Thanks for the re-assuring post. I 'spose that the ribbon is just a part of the tweeter and, as a friend told me, the material is very tough and unless it's torn (or has holes in it) there shouldn't be any sonic difference.

23rd March 2005, 09:54 PM	#10
budwiser diyAudio Member Join Date: Jan 2004 Location: Greenwood, IN	No test where done, but I could do that. At one time I had the grills that cover the tweeter off and something could have happened then. I did'nt really notice it until weeks later when I was testing the results of the mortite appplication. I noticed thru the grill that the tweeter looked alittle odd compared to t he other. Took the top of and it was wrinkled alittle.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)