Realistic Mach 2 mods

[bre's dad]

Mach 1 modifications are well documented, largely thanks to VL. Has anyone made or wrote up a guide to modifying Mach 2's? i have a set I thought sounded very muddy and really not that great. I recapped the crossovers (Dayton Audio caps), had the woofers refoamed and replaced the midrange speakers & added more batting in the cabinet. After doing these, I compared them to a friend's Mach 2's that are all original (he did refoam the woofers). The highs are mine are a lttle more clear and brighter, but the mids are still a little muddy and muffled (they sound better than the original mids but not by much). Other than the highs coming out more on mine, his sounded about the same. What else can be done to these to make them sound clearer and better?

 

[tiga]

Do the Mach 2's have a control pot for the mids? You may want to try deoxit'ing that and see if it helps.

Mach 1 modifications are well documented, largely thanks to VL. Has anyone made or wrote up a guide to modifying Mach 2's? i have a set I thought sounded very muddy and really not that great. I recapped the crossovers (Dayton Audio caps), had the woofers refoamed and replaced the midrange speakers & added more batting in the cabinet. After doing these, I compared them to a friend's Mach 2's that are all original (he did refoam the woofers). The highs are mine are a lttle more clear and brighter, but the mids are still a little muddy and muffled (they sound better than the original mids but not by much). Other than the highs coming out more on mine, his sounded about the same. What else can be done to these to make them sound clearer and better?

 

[bre's dad]

yeah. that was the first thing I did when I got the speakers. I think its the frequencies it is crossed over at. That or the new caps haven't broken in yet. After putting a new midrange speaker n there, it sounds the same.

 

[Copa1934]

Mach 1 modifications are well documented, largely thanks to VL. Has anyone made or wrote up a guide to modifying Mach 2's? i have a set I thought sounded very muddy and really not that great. I recapped the crossovers (Dayton Audio caps), had the woofers refoamed and replaced the midrange speakers & added more batting in the cabinet. After doing these, I compared them to a friend's Mach 2's that are all original (he did refoam the woofers). The highs are mine are a lttle more clear and brighter, but the mids are still a little muddy and muffled (they sound better than the original mids but not by much). Other than the highs coming out more on mine, his sounded about the same. What else can be done to these to make them sound clearer and better?

I have 4 of the soft dome mids RS sold off the shelf, very similar in design to the ones used in AR3a speakers. I'm thinking of swapping those in place of the current mid to see if there is any improvement. The crossover is very close to the recommended one for the soft dome, though it's actually rated down to 600hz, but likely not very audible at that level and possibly damaging at higher volumes.

I sold my originals after getting my Mach One's, but then missed them later. Friday a friend brought over a pair of Two's he found at a Y.S. We barter stuff, I fix his stuff and he gives me stuff in return. Cool deal for both of us. I've already installed a "fixed" woofer and will replace the other today or tomorrow, hopefully. Then I'll figure out how to adapt the soft dome and see how that works out. If I do complete this mod I'll post my thoughts on it.

In the mean time I'll be watching this thread. Some people have stuffed/closed the port for a tighter bass response. I've installed a Two woofer in a modded One cabinet and the bass response was nice and tight.

 

[dc270]

You might want to look at cabinet bracing, painting the woofer & mid with the super glue as VL did, spray deaded or foam wrap the woofer frame to prevent ringing, are a few ideas I can offer.....
DC

 

[Blast]

I'll be watching this thread. I've got a pair of Two's and a pair of T-120's and really have a difficult time telling the difference between them.

The only thing I've done to the Mach Two's is to replace the foam on the mids. The cab's are a little waterlogged on their bottoms but not enough to affect operation.


6/9/19 UPDATES: Put the missing (due to Photobucket) 2008 photo in, above. Also, the Mach Two woofer surrounds were also replaced (in 09/2015).
Brian

 

[bre's dad]

I'll be watching this thread. I've got a pair of Two's and a pair of T-120's and really have a difficult time telling the difference between them.

The only thing I've done to the Mach Two's is to replace the foam on the mids. The cab's are a little waterlogged on their bottoms but not enough to affect operation.

Brian

Alot of it is the crossover points on the crossover I'm sure. Seems like if someone took the time to figure out the curves & what would work best, like VL did on the Mach 1's it would be helpful. I have neither the knowledge or gear (or time) to do it. I've replaced the mids and they still sound about the same. When I first got them I knew they had sat unused for a long time and going on 20-25 years old figured they were due for a recap. I recapped them and the highs are brighter and more brilliant, but the mids are still muddy.

 

[Blast]

What were the values of the caps you replaced?

 

[bre's dad]

I would need to pull it apart & check. I replaced it with the same values as original. Will do that tomorrow.

 

[pognoot]

Wow. I am sure this has been covered here before, but the port size on the Mach 2s looks way too small for the enclosure and woofer size. Surprised if that thing wouldn't make all sorts of ghastly turbulance noise when the woofer is pushing hard.

 

[Copa1934]

Wow. I am sure this has been covered here before, but the port size on the Mach 2s looks way too small for the enclosure and woofer size. Surprised if that thing wouldn't make all sorts of ghastly turbulance noise when the woofer is pushing hard.

Only thing I recall reading is comments on the cabinet size, which compared to similar "era" speakers with 15's is on the small side. I would equate this more to shipping costs than a conscious performance decision. Compared to earlier Pioneer and Sansui speakers (which I have a few) the Two cabinets are significantly bigger.

Hope there is more progression in this thread as the Two's are abundant and can be had cheap. Two's used to be the mains in my HT system (too long a story why they aren't), but my recent acquisition has me thinking about giving them a go again now that my ears have acclimatized to my RTR's.

 

[dc270]

Go to PE and look at the cone mids from Tang Band & Vifa- maybe others. Some of them really look good. I have used and really like the Bamboo cone mids from Tang Band and they sound VERY good! If it were me I would certainly look into replacing that tinny cone mid with a quality unit.

Not sure what xover freq is between the mid & woofer but I suspect it to be fairly high, like 1000hz or more. I would consider lowering that to 500hz, 2nd order. Pushing those inexpensive 15" woofers up that high is usually not good to do as they will break up or become directional, etc. I think the high point of the Mach 2 is the tweeter- upgrade he cone mid and you may well have a much better sounding speaker.
DC

 

[Copa1934]

Go to PE and look at the cone mids from Tang Band & Vifa- maybe others. Some of them really look good. I have used and really like the Bamboo cone mids from Tang Band and they sound VERY good! If it were me I would certainly look into replacing that tinny cone mid with a quality unit.

Not sure what xover freq is between the mid & woofer but I suspect it to be fairly high, like 1000hz or more. I would consider lowering that to 500hz, 2nd order. Pushing those inexpensive 15" woofers up that high is usually not good to do as they will break up or become directional, etc. I think the high point of the Mach 2 is the tweeter- upgrade he cone mid and you may well have a much better sounding speaker.
DC

I would certainly examine the mid closely as they have foams that deteriorate (which I believe is the reason I parted with mine). If they are bad (cracking, breaking up, etc.) that will cause weak performance in the mids and eventual damage. I'll have to check mine, however, I'm still thinking about changing out the mids for the soft domes I have since they are a very close match for the xover, but better performers.

In regards to the 1000hz crossover, you are correct. VL concluded that the xover "should" be lower (in reference to Mach One's, but actually still applicable to Two's and Three's) however, due to the limitations of the mids used in the respective speaker systems the woofer had to be crossed over at a higher frequency.

I'm working through the "draft" of a Tier-2 update based on the Mach One thread and PM's between myself and VL before he/she went MIA. I think people will get a kick out of the mod I came up with that requires no further "physical" mods (aside of the Tier-1) to the cabinet to further extend the bottom end. Also I have a project using the Mach drivers for a cool Frankenspeaker, of sorts to be published in the near future (I hope).

 

[sealy]

When the woofers need refoaming, so do the mids. If you haven't done the mids, now's the time.

 

[Copa1934]

Update

...The highs are mine are a lttle more clear and brighter, but the mids are still a little muddy and muffled (they sound better than the original mids but not by much)...

OK, so I swapped the mid out of one and replaced with RS 40-1281a soft dome mid and wow, no more muddy sound. However, I did notice that the mid surround was stiff and not plyable. So, that means re-foam as the stiff foam will clearly dampen the speakers response.

That said, I'm not sure the surround fix will quite match the soft dome. In fact when my wife and I were A/Bing them both of us noticed the speaker with the soft dome had to be turned down, via the L-pad. Sound was crisper and livelier than with the original mid. These mids show up constantly so they're readily available. I think it's a serious improvement, in fact based on what little we listened to them they seemed to open the speakers up as well so I'm anticipating some better imaging as well. Huge improvement in cymbals, vocals, etc. So far nothing appears to be missing or lacking so the current crossover seems to be compatible as well.

 

[dc270]

What is you xover freq points?
DC

 

[RayW]

Alot of it is the crossover points on the crossover I'm sure. Seems like if someone took the time to figure out the curves & what would work best, like VL did on the Mach 1's it would be helpful. I have neither the knowledge or gear (or time) to do it.

Feel like a road trip? I'll be in the Indianapolis area next Thursday.

 

[bre's dad]

I've tried a few different midranges, including the one you're referencing. They're all about the same. What I think needs to be done is to figure out better crossover points. All of the drivers hooked up straight (watching the volume of course) sound and play fine. Should have done that before rebuilding the x-overs but I thought the were just way out of spec & replacing them with the same values would help. It did the highs some but not the mids.

 

[Copa1934]

I've tried a few different midranges, including the one you're referencing. They're all about the same. What I think needs to be done is to figure out better crossover points. All of the drivers hooked up straight (watching the volume of course) sound and play fine. Should have done that before rebuilding the x-overs but I thought the were just way out of spec & replacing them with the same values would help. It did the highs some but not the mids.

Weird, my wife really liked the sound of the speaker with the soft dome. I have to wonder what is up with your system as the difference was quite noticeable, and better in mine. I've brought them home and plan to hook them up to the HT system first, then take them upstairs to A/B with about 6 other speakers, including 4024a Mach One's. I don't recall that I mentioned this but I but the receiver in mono mode to avoid engineering tweaks to separate instruments, vocals, etc. Very apparent improvement with the soft dome.

 

[bre's dad]

I tried running in mono mode too. I ended up putting the soft dome mids in another set of speakers deemed less worthy. These will probably be shelved for now as I have the parts on hand now to rebuild those crossovers.