Cerwin Vega Frankenstein Project

[Carverpro 672]

So to get the best possible sound I have decided to modify my At-15's. 

Top pic is how it sits now. Se-380 woofer in at-15 cabinets for stronger bass response.  Note the difference between mid size between the at-15's and se380's. And the difference between the 2 woofers.

[Carverpro 672]

Two different type of tweeters. I went with the At-15's.  Took out all the drivers and wiring . Built a custom set of front baffles out of 3/4" mdf all ready to be cut out and transplanted into the front of At-15 enclosures. I would have preferred the same midrange/ tweeter positioning as stock...but the se380's are massive compared to the At15's....so I had to re- design it.

Edited April 1, 2019 by Carverpro

[Carverpro 672]

New front baffle is in place. All that is needed to do now is silicone and screw it down.  Change the internal brace location. Move the crossover and mid/tweet controls to the back of the outside box...pump about 500 watts into it and check for rattling noises coming from the new baffle. Already had the drivers in place. Measuring the distance from the dustcap on the woofer cone to the dustcap on the midranges to the center of the tweeter diaphragm on both speakers to make sure everything is identical. 

 

 

 

Edited April 3, 2019 by Carverpro

[Carverpro 672]

Disregard

Thanks

Edited April 3, 2019 by Carverpro

[itchitch 4,495]

Looks like a fun project!

[danowood 2,167]

Careful, speaker box's are designed for the characteristics of the drivers with a specific formula.  having a tuned box to the drivers are of great importance.  Looking good on your project, I wish you a successful journey in replicating the sound you seek. 

[Carverpro 672]

...here we go

[Carverpro 672]

7 hours ago, danowood said:

Careful, speaker box's are designed for the characteristics of the drivers with a specific formula.  having a tuned box to the drivers are of great importance.  Looking good on your project, I wish you a successful journey in replicating the sound you seek. 

Yes I hear what you are saying.  Now if the woofer is tuned to just the area behind the woofer( there Is carpeting that separates the woofer compartment from the mids and tweet)....and port size/length...then there shouldn't be a problem.

...If the woofer is being tuned to the whole area inside the cabinet and port size/ length then it's going to move the tuning of the box up ever so slightly.  If you look at the pic the new baffle is sitting on top of the old one that I modified to make room for the bigger mids / tweeter location. It is 3/4" thick.

....Going by my subwoofer box building and tuning days...taking into account that the bigger size 6.5" se380 mids are taking up a bit more of internal space compared to the 5" ones that once rested there...I believe it shouldn't affect the tuning any amount that's going to have a negative impact.

...Stock cabinet tuning was 28hz. The mids and tweet are sitting 3/4" higher on the face plate. That and the  difference in basket size between the two mids...might bring the tuning up to 29hz at the most...I'm hoping.  Bigger question is the re-arrangment of the mids and tweet. It will either make an improvement with the different placement and or bigger mids. I wont know until I hear it running.

Edited April 3, 2019 by Carverpro

[Carverpro 672]

I will say that this is a lot of work to change out a few midranges..??

[Brian_at_HHH 2,691]

22 minutes ago, Carverpro said:

I will say that this is a lot of work to change out a few midranges..

 

Self flagellation at its best!      Glad to see someone else doing it instead of me - the difference is the results for you will be great.   My attempts usually just circle back to trying to get back to square one with as little lost ground as possible.  

 

Those are going to Rock when you are done.  

[Carverpro 672]

3 hours ago, Brian_at_HHH said:

 

Self flagellation at its best!      Glad to see someone else doing it instead of me - the difference is the results for you will be great.   My attempts usually just circle back to trying to get back to square one with as little lost ground as possible.  

 

Those are going to Rock when you are done.  

Yeah ..to be perfectly honest with you, I was not expecting this to be so labour intensive. If I knew then what I know now...I probably would either have left well enough alone  ...or looked for a real potent set of 5" mids to fit in the stock location.

...I actually do have ocd...so now I have to finish the project...lol. Tonight I made some bracing to replace the ones I had to rip out to reinforce the front baffle. I also got the baffles siliconed and screwed down. 

...Only thing left to do is move the crossover and controls to the back and lengthen the wires and install all the drivers. The at15 tweeters I'm using sound better than the se380 units and the se380 mids sound better than the at15's. Hopefully your right and they do end up rocking good.?

[Bobby1970 1,451]

13 hours ago, Carverpro said:

Going by my subwoofer box building and tuning days

...you miss those days lol, please post pictures of the new bracing, thank you,

 

"That Rocks"

[Brian_at_HHH 2,691]

I've learned that if we knew what the work would actually entail, that very few projects would ever be taken on.  Embrace it  if not for our gulable optimistim  the human race woul still be living in caves, and listening to rock drums.  Mind you, with the right rocks you could probably get some decent bass...

[Carverpro 672]

She ain't pretty...but the faceplate is strong and rigid.  Plan on laying crushed velvet over it like on the se380's. But that's just for later....finishing touches. Have to first lay a healthy dose of carver power into them to check for unusual noises coming from the new faceplate.

[Bobby1970 1,451]

...exactly what I am thinking for that kind of cabinet, thank you, hope you're not forgetting some glue..maybe this track may help check some things..

 

[Carverpro 672]

Relocated the crossover/controls to the rear of the cabinet. All I have to do now is lengthen the crossover wires...install the drivers and wake the dead with about 500 watts.

[johnrotten 1,092]

I just took a critical listed to my HED U-351's and heard a buzz. Apparently I reversed + and - so the woofer on right side was moving inward instead of outward. Now the surround has began to pull apart from the cone in a 4" long strip, creating the buzz. I don't have any of the SS glue left from the re-foam a few years ago. Any suggestions as to what adhesive to use just to get by until it's time for a full re-foam?

[Carverpro 672]

You can try what I used. Dont laugh it worked excellent.  Looks bad but is stronger than silicone i believe...red automotive gasket maker. Check out the pic in this thread of the at15 woofer. It's all around the surround. That's when my Carver pm1.5a ripped the surround from the cone.

[Carverpro 672]

You can get it at " Canadian Tire "

[johnrotten 1,092]

I was thinking more along the lines of contact or rubber cement that would be easily cleaned up at next re-foam. Crappy Tire sells it too. I have had these speakers over 30 years now and re-foamed them twice using Simply Speakers products. No offense but the gasket maker  looks like crap and probably will for the life of the cone, regardless of new surrounds. I will probably bite the bullet and order the SS kit now and an extra tube of glue. I found out the hard way that leftover glue doesn't stick and always use a fresh tube.

[Carverpro 672]

2 hours ago, johnrotten said:

I was thinking more along the lines of contact or rubber cement that would be easily cleaned up at next re-foam. Crappy Tire sells it too. I have had these speakers over 30 years now and re-foamed them twice using Simply Speakers products. No offense but the gasket maker  looks like crap and probably will for the life of the cone, regardless of new surrounds. I will probably bite the bullet and order the SS kit now and an extra tube of glue. I found out the hard way that leftover glue doesn't stick and always use a fresh tube.

True enough. It does look like crap...lol.I tried another adhesive before that and it didn't take. My plan was to change out the woofers so I wasn't really concerned how it looked at the time. I didn't expect the gasket maker to work neither...but it's been holding up to a lot of pounding.  As a side note...both woofers were fresh refoams from a guy who has been freshening up cerwin vega woofers for 25 years. Couldn't handle the carver amp however .?

[Brian_at_HHH 2,691]

The red gasket maker should go fine on a Cerwin Vega.  You can just refer to the spots as being Carver rash.  ?

 

BTW, thanks for the idea - I don't need it now, but it's great to have that in my back pocket, in case.

[Carverpro 672]

Crossovers are modified.  Had to lengthen the wires going to the woofer, both mids and tweeter. Only thing left to do now is put all the drivers back in and see how it sounds. 

[Carverpro 672]

This " little project " is turning into a nightmare. I made one little critical mistake. I didnt take into account that the 380 mids have an open basket compared to the at15's that are completely sealed.

...The bass from the woofer is causing the midranges to act as woofers and causing too much travel. Too bad because the bigger mids definately improved the sound.

...I am not even sure if I have room to build a mini enclosure behind the mids to seal them up. Even if i did...that would definately hurt the tuning of the box.

...could use some foam sealed  baffles that are used in car doors...but I'm not sure if i can find any that would be a perfect fit for the 380 mids.

...Only other choice would be to built a separate sealed enclosure and mount it on the front speaker baffle. Basically...the mids and tweeter would be in the same location as i have them now...but would be sticking out about 3 " past the woofer. I have no idea what this would do to the sound.

...or i can find a way to seal the midrange basket holes  up. I tried shoving insulation in the basket holes. This helped..but not much. Maybe some thin rubber and contact cement to go around the outside of the basket and cover the holes. But are these holes providing any cooling to the voice coil at all. Anybody have any ideas.

Edited April 6, 2019 by Carverpro

[Carverpro 672]

I could use some velcro strips and seal up the basket holes..I suppose this might work.