You can never have too much power......

[Volvohead]

You need to anchor and mass-load the enclosure. Your LF drivers are overpowering the original cabinet design, which was never designed for that kind of response.

This will also help reduce cabinet resonances, which I'm sure are excessive. Resonances reduce and muddy bass response, among other bad things.

Rubber feet may keep the enclosures from walking, but it may not control the cabinet resonances.

Unless the floor is concrete, you don't want the cabinets too firmly bonded to the floors, or you will just be transmitting the cabinet resonance everywhere else.

Unless the floors are concrete, I would suggest spikes to start. If you have sensitive floor coverings, you can place them on nickles to protect them.

As far as mass loading, the quickest and easiest way is to stack weight on top of the cabinets. I've seen books, bricks and even cinder blocks used for this purpose. You can also directly fasten the cabinet (with screws or bolts) to a high mass/higher density object sitting on the floor (one example: a sand-filled platform/box). Or you can do both.

This will reduce, but not eliminate cabinet resonances. It's hard to fix a suboptimal front baffle or unbraced joints. Higher quality speakers will have all sorts of internal bracing and chambers to address these issues, most of which are usually lacking below a certain price point. Big, cheap floorstanders with megawide woofers are usually the prime examples.

There are some other tricks to reduce resonances, but they involve getting into the cabinets, so I would start with the above.

 

[OVERKILL]

Originally Posted By: Volvohead
You need to anchor and mass-load the enclosure. Your LF drivers are overpowering the original cabinet design, which was never designed for that kind of response.

This will also help reduce cabinet resonances, which I'm sure are excessive. Resonances reduce and muddy bass response, among other bad things.

Rubber feet may keep the enclosures from walking, but it may not control the cabinet resonances.

Unless the floor is concrete, you don't want the cabinets too firmly bonded to the floors, or you will just be transmitting the cabinet resonance everywhere else.

Unless the floors are concrete, I would suggest spikes to start. If you have sensitive floor coverings, you can place them on nickles to protect them.

As far as mass loading, the quickest and easiest way is to stack weight on top of the cabinets. I've seen books, bricks and even cinder blocks used for this purpose. You can also directly fasten the cabinet (with screws or bolts) to a high mass/higher density object sitting on the floor (one example: a sand-filled platform/box). Or you can do both.

This will reduce, but not eliminate cabinet resonances. It's hard to fix a suboptimal front baffle or unbraced joints. Higher quality speakers will have all sorts of internal bracing and chambers to address these issues, most of which are usually lacking below a certain price point. Big, cheap floorstanders with megawide woofers are usually the prime examples.

There are some other tricks to reduce resonances, but they involve getting into the cabinets, so I would start with the above.


Floor is hardwood, what are these "spikes" you speak of?

A sand-filled box, I assume you mean like a wooden enclosure that I would fill with sand and then bolt the speaker to? That sounds intriguing! Only issue is the fibre board these cabinets are made of isn't the best material to run fasteners through

 

[Volvohead]

Isolation spikes used in audio are metal cones that terminate to a sharp point. The old trade name was "tiptoes", but they are available from a variety of sources and in different designs. You can pay a few dollars for a set from an electronics supply house, or $100 for an "audiophile" set at a dimly lit salon. You can even use a crude substitute such as nails. Higher end speakers often come pre-fitted with isolation spikes. So do better speaker stands.

The idea is to isolate, or de-couple, the component. This protects the component from vibrations reaching it (as in the case of a turntable or other mechanical front end component), and from its own vibrations spreading past its confines (as in the case of speakers). Vibration energy has a harder time migrating when it must pass through a point. Spikes can be fitted point up or point down.

FWIW, vibration control strategies and the use of mass vary depending on the component and even the brand. Some turntables, for instance, behave best with very low mass decoupling (like a thin lightweight tubular stand). Others are better with very massive methods (i.e. concrete stands). It's as much an art as science.

With loudspeakers, it is the component that is generating the energy, so you want to not let it go in directions or reach places that are counterproductive to the output (vibrating baffle boards, floors, etc). So the strategies are a little different.

In a perfect loudspeaker, the only thing that should move are the driver diaphragms and the forward air mass they are exciting, with all else at static rest. But that is never the case in a dynamic design. A driver is radiating as much energy back into the cabinet as it is forward in many instances. It has to go somewhere. Just put your hand on any loudspeaker for the proof. This excess energy is also sometimes redirected to positive effect by way of passive radiators and bass ports. Dissipating it before it reaches the cabinet is good, but you can never dissipate it all.

With hardwood floors, you will want to use the nickle pads suggested (coins) to protect the floor. Cost: 15-20 cents per speaker (depending on a 3 or 4 point mount). Experiment with spikes both ways; spike to speaker, and spike to floor. You are looking to decouple the speaker from the floor (while keeping it fixed). The added mass load will help keep it fixed, and also help dissipate the excessive LF energy that is radiating into the cabinet.

I would suggest that you start with just stacking mass on top of the speaker. No offense, but these are not furniture grade cabinets, and aren't really deserving of extensive effort. As with anything audio, don't be shocked if for some strange reason the speaker sounds different in a negative way. Top speaker designers often juggle many different variables in their design, including expected cabinet resonances. You have substantially changed the original design, however, so I would expect an improvement in this instance.

The more I think of your situation, the more inclined I am to try a high mass stand with spikes. It can be short, and you can build a tilt into it if necessary. Set your speakers on the spikes, and then stack some additional mass on top.

The trick is not to get sucked into the audiophile gadget game (aka snake oil), and wind up spending hundreds or thousands of dollars on what can be had at HD or Lowes for $5-10.

 

[OVERKILL]

Originally Posted By: Volvohead
Isolation spikes used in audio are metal cones that terminate to a sharp point. The old trade name was "tiptoes", but they are available from a variety of sources and in different designs. You can pay a few dollars for a set from an electronics supply house, or $100 for an "audiophile" set at a dimly lit salon. You can even use a crude substitute such as nails. Higher end speakers often come pre-fitted with isolation spikes. So do better speaker stands.

The idea is to isolate, or de-couple, the component. This protects the component from vibrations reaching it (as in the case of a turntable or other mechanical front end component), and from its own vibrations spreading past its confines (as in the case of speakers). Vibration energy has a harder time migrating when it must pass through a point. Spikes can be fitted point up or point down.

FWIW, vibration control strategies and the use of mass vary depending on the component and even the brand. Some turntables, for instance, behave best with very low mass decoupling (like a thin lightweight tubular stand). Others are better with very massive methods (i.e. concrete stands). It's as much an art as science.

With loudspeakers, it is the component that is generating the energy, so you want to not let it go in directions or reach places that are counterproductive to the output (vibrating baffle boards, floors, etc). So the strategies are a little different.

In a perfect loudspeaker, the only thing that should move are the driver diaphragms and the forward air mass they are exciting, with all else at static rest. But that is never the case in a dynamic design. A driver is radiating as much energy back into the cabinet as it is forward in many instances. It has to go somewhere. Just put your hand on any loudspeaker for the proof. This excess energy is also sometimes redirected to positive effect by way of passive radiators and bass ports. Dissipating it before it reaches the cabinet is good, but you can never dissipate it all.

With hardwood floors, you will want to use the nickle pads suggested (coins) to protect the floor. Cost: 15-20 cents per speaker (depending on a 3 or 4 point mount). Experiment with spikes both ways; spike to speaker, and spike to floor. You are looking to decouple the speaker from the floor (while keeping it fixed). The added mass load will help keep it fixed, and also help dissipate the excessive LF energy that is radiating into the cabinet.

I would suggest that you start with just stacking mass on top of the speaker. No offense, but these are not furniture grade cabinets, and aren't really deserving of extensive effort. As with anything audio, don't be shocked if for some strange reason the speaker sounds different in a negative way. Top speaker designers often juggle many different variables in their design, including expected cabinet resonances. You have substantially changed the original design, however, so I would expect an improvement in this instance.

The more I think of your situation, the more inclined I am to try a high mass stand with spikes. It can be short, and you can build a tilt into it if necessary. Set your speakers on the spikes, and then stack some additional mass on top.

The trick is not to get sucked into the audiophile gadget game (aka snake oil), and wind up spending hundreds or thousands of dollars on what can be had at HD or Lowes for $5-10.


Would you mind providing a picture of what you mean by a high mass stand with spikes? I THINK I get what you are describing, but want to be sure.

 

[AVB]

Spikes http://www.parts-express.com/pe/showdetl.cfm?Partnumber=240-670

 

[OVERKILL]

Originally Posted By: AVB
Spikes http://www.parts-express.com/pe/showdetl.cfm?Partnumber=240-670


K, got that part, but what about the high mass stand?

 

[JOD]

Originally Posted By: OVERK1LL
Originally Posted By: AVB
Spikes http://www.parts-express.com/pe/showdetl.cfm?Partnumber=240-670


K, got that part, but what about the high mass stand?


I can take a picture of my Snell E3 stands later to give you an idea, but basically they're a foot tall box and the same shape as the speaker. There's a 2" recess and the speaker just drops into them. They're just made out of 3/4" plywood and then filled with sand.

My Snells came with these, but you could make them in an afternoon for less than $40.00. The spikes then mount with t-nuts to the bottom of the stands. There's a massive difference in sound with and without the stands. It's definitely a worthwhile upgrade.

 

[OVERKILL]

Originally Posted By: JOD
Originally Posted By: OVERK1LL
Originally Posted By: AVB
Spikes http://www.parts-express.com/pe/showdetl.cfm?Partnumber=240-670


K, got that part, but what about the high mass stand?


I can take a picture of my Snell E3 stands later to give you an idea, but basically they're a foot tall box and the same shape as the speaker. There's a 2" recess and the speaker just drops into them. They're just made out of 3/4" plywood and then filled with sand.

My Snells came with these, but you could make them in an afternoon for less than $40.00. The spikes then mount with t-nuts to the bottom of the stands. There's a massive difference in sound with and without the stands. It's definitely a worthwhile upgrade.


Definitely interested! Thank you

 

[Volvohead]

OK,

I think you've got the right idea.

A short box filled with sand, spikes up into the speakers, would work.

If you want to try something cheaper and easier (no assembly), even a flat paver block might work. Two pavers, one on top and one at the base, speaker sandwiched between them, might be enough to do the task. Two pavers are a couple of dollars. You can paint them any color you like. Very little at risk if you don't like the result.

That this speaker is walking the floor says a lot of things. These cabinets are not really meant for what you're using them for. The original design cutoff on them is 30hz. I'm sure it's vinyl-covered MDF. Once you move up to floor standers, that can be difficult to work with. Not to generalize, but a well made floor standing speaker should be difficult to pick up. I need help lifting my Thiels, and I'm still a fairly strong man.

Unless you've got the time to kill or there's something really sentimental about them, I honestly wouldn't expend a lot of time/effort on these speakers. Once past a point, you're better off either building new cabinets or getting something else.

If you're really a bass head looking for very high output levels, there are better choices than that CV. Certain bigger horn-loaded Klipsches immediately come to mind, which will blow your walls out with much less power. Not that you want to splurge on a K-horn, but there are others, including some kits and designs based on them for the DIY.

Don't overlook the Xover. In many respects, a good or bad Xover can make or break the whole thing. Nothing sounds worse than a ten cent Chinese 'lytic separating you from your music, which is where most makers cheap out. It's amazing how so many enthusiasts wax on about their wonderful amplifiers that they've invested in, never knowing that this is what the output then has to pass through.

 

[Quest]

Originally Posted By: Volvohead
OK,

I think you've got the right idea.

A short box filled with sand, spikes up into the speakers, would work.

If you want to try something cheaper and easier (no assembly), even a flat paver block might work. Two pavers, one on top and one at the base, speaker sandwiched between them, might be enough to do the task. Two pavers are a couple of dollars. You can paint them any color you like. Very little at risk if you don't like the result.

That this speaker is walking the floor says a lot of things. These cabinets are not really meant for what you're using them for. The original design cutoff on them is 30hz. I'm sure it's vinyl-covered MDF. Once you move up to floor standers, that can be difficult to work with. Not to generalize, but a well made floor standing speaker should be difficult to pick up. I need help lifting my Thiels, and I'm still a fairly strong man.

Unless you've got the time to kill or there's something really sentimental about them, I honestly wouldn't expend a lot of time/effort on these speakers. Once past a point, you're better off either building new cabinets or getting something else.

If you're really a bass head looking for very high output levels, there are better choices than that CV. Certain bigger horn-loaded Klipsches immediately come to mind, which will blow your walls out with much less power. Not that you want to splurge on a K-horn, but there are others, including some kits and designs based on them for the DIY.

Don't overlook the Xover. In many respects, a good or bad Xover can make or break the whole thing. Nothing sounds worse than a ten cent Chinese 'lytic separating you from your music, which is where most makers cheap out. It's amazing how so many enthusiasts wax on about their wonderful amplifiers that they've invested in, never knowing that this is what the output then has to pass through.


My sentiments on this said subject, thank you!

Q.

 

[JOD]

Here you go--sorry for the lousy phone pics. As you can see, the bottom of the speaker has a recessed piece on it (it's just a 3/4" piece of mdf or plywood about 2" smaller than the footprint of the speaker. Then, it just drops into the stands.

The spikes actually just attach to the stands, not the speakers. While theoretically less-than-ideal, it works fine. A single sheet of plywood/MDF would be all you need. You could double up 1/2" sheet stock to make it thicker, and just don't extend it all the way up to make the recess for the speaker to sit. Since you're now well on your way to making your own speakers, you may as well buy a biscuit joiner (if you don't have one) so you can make the stands. It's not necessary, but it sure is nice.

I agree w/Volvohead though. Don't invest too much time or $$ in these speakers. That said, this would be a fun, cheap project.

 

[sleddriver]

Originally Posted By: OVERK1LL
Floor is hardwood, what are these "spikes" you speak of?

A sand-filled box, I assume you mean like a wooden enclosure that I would fill with sand and then bolt the speaker to? That sounds intriguing! Only issue is the fibre board these cabinets are made of isn't the best material to run fasteners through

 

[OVERKILL]

Originally Posted By: Volvohead
OK,

I think you've got the right idea.

A short box filled with sand, spikes up into the speakers, would work.

If you want to try something cheaper and easier (no assembly), even a flat paver block might work. Two pavers, one on top and one at the base, speaker sandwiched between them, might be enough to do the task. Two pavers are a couple of dollars. You can paint them any color you like. Very little at risk if you don't like the result.

That this speaker is walking the floor says a lot of things. These cabinets are not really meant for what you're using them for. The original design cutoff on them is 30hz. I'm sure it's vinyl-covered MDF. Once you move up to floor standers, that can be difficult to work with. Not to generalize, but a well made floor standing speaker should be difficult to pick up. I need help lifting my Thiels, and I'm still a fairly strong man.


They aren't light, but I can certainly pick them up myself and move them around

That being said, the woofers themselves are heavy......

As far as the cabinet construction, that's exactly right. They are 3/4" MDF with vinyl "wood" coating.

Quote:
Unless you've got the time to kill or there's something really sentimental about them,


I bought them when I was a poor University student, so yes, I do have some sentimental attachment to them

Quote:
I honestly wouldn't expend a lot of time/effort on these speakers. Once past a point, you're better off either building new cabinets or getting something else.


And I don't intend on taking them much beyond what we are currently discussing if that helps?

Quote:
If you're really a bass head looking for very high output levels, there are better choices than that CV. Certain bigger horn-loaded Klipsches immediately come to mind, which will blow your walls out with much less power. Not that you want to splurge on a K-horn, but there are others, including some kits and designs based on them for the DIY.


I'll keep that in mind, thanks.

Quote:
Don't overlook the Xover. In many respects, a good or bad Xover can make or break the whole thing. Nothing sounds worse than a ten cent Chinese 'lytic separating you from your music, which is where most makers cheap out. It's amazing how so many enthusiasts wax on about their wonderful amplifiers that they've invested in, never knowing that this is what the output then has to pass through.


I doubt the X-overs are Chinese based only on the fact of how old these cabinets are. I can tear into one and check if you want though?

 

[sleddriver]

WOW...my lengthy response just evaporated because I hit the wrong key!! I was nearly done too. And I was over the editing time cutoff! @#$! I hate it when that happens. . . very, very frustrating! Now I have to go as I've run out of time...dang! Perhaps I can resurrect it all later. Sorry!

 

[OVERKILL]

Originally Posted By: JOD
Here you go--sorry for the lousy phone pics. As you can see, the bottom of the speaker has a recessed piece on it (it's just a 3/4" piece of mdf or plywood about 2" smaller than the footprint of the speaker. Then, it just drops into the stands.

The spikes actually just attach to the stands, not the speakers. While theoretically less-than-ideal, it works fine. A single sheet of plywood/MDF would be all you need. You could double up 1/2" sheet stock to make it thicker, and just don't extend it all the way up to make the recess for the speaker to sit. Since you're now well on your way to making your own speakers, you may as well buy a biscuit joiner (if you don't have one) so you can make the stands. It's not necessary, but it sure is nice.

I agree w/Volvohead though. Don't invest too much time or $$ in these speakers. That said, this would be a fun, cheap project.

Awesome, exactly what I'm looking for! Thank you!

 

[Volvohead]

Originally Posted By: OVERK1LL


I doubt the X-overs are Chinese based only on the fact of how old these cabinets are. I can tear into one and check if you want though?


Since they are important to you, I looked a little more.

There's a replacement Xover board over on Ebay, so I was able to see what you have. Here: http://www.ebay.com/itm/CERWIN-VEGA-D-3-CROSSOVER-PAIR-/390420405803

It's a very barebones affair hot glued to the spring clip panel. Very typical at that price point, even today.

It looks like cheaper films were used on these. Better than electrolytics, but nothing impressive. But they should still be good. This is not a high-power affair. If you can, I'd bypass the tweeter volume pot in favor of a fixed value resistor and upgrade the skimpy wiring on them, at least to the LF driver.

I don't know how you get any meaningful current though those little spring clips. Maybe you could fit some binding posts on these.

That of course presumes that the Xover still fits the driver compliment.

I'm only guessing, as I don't have all the values off the parts, but the general design suggests that wider range drivers were originally specified for this one. I suspect you may have a response gap in the lower midrange/upper bass with what you now have. What most people think of as "bass" is really the middle to upper end of the bass region (100-250hz).

The original woofer on this probably was a wider range unit extended into those higher octaves (250hz+), at the expense of the mid to sub bass region. Your replacement subwoofer is probably tuned for the sub bass, and is probably rolling off too quickly before the midrange takes over.

Just a guess.

To show how you can take these things, here's a reworked Xover - before and after - for a classic era Klipsch 3-way that we use in our "beater" system. The layout is modest, but the parts are first-class. The caps are later covered with bluetack to "pot" them against internal resonances. The sonic improvement is profound:

 

[Volvohead]

OK,

Food for thought:

When you run less hungry speakers, it allows for electronics like this:

It just turned 50. Fully reconditioned about 12 years ago.
Had it on this morning. A whopping 30 wpc.

No, it doesn't (and can't) drive our big Thiels.

But with the right speakers, it sings as sweetly as it did in '62. I'll match it against any stereo receiver ever made for overall tone and presence.

Hijack over.

 

[OVERKILL]

Originally Posted By: Volvohead
Originally Posted By: OVERK1LL


I doubt the X-overs are Chinese based only on the fact of how old these cabinets are. I can tear into one and check if you want though?


Since they are important to you, I looked a little more.

There's a replacement Xover board over on Ebay, so I was able to see what you have. Here: http://www.ebay.com/itm/CERWIN-VEGA-D-3-CROSSOVER-PAIR-/390420405803

It's a very barebones affair hot glued to the spring clip panel. Very typical at that price point, even today.

It looks like cheaper films were used on these. Better than electrolytics, but nothing impressive. But they should still be good. This is not a high-power affair. If you can, I'd bypass the tweeter volume pot in favor of a fixed value resistor and upgrade the skimpy wiring on them, at least to the LF driver.

I don't know how you get any meaningful current though those little spring clips. Maybe you could fit some binding posts on these.

That of course presumes that the Xover still fits the driver compliment.

I'm only guessing, as I don't have all the values off the parts, but the general design suggests that wider range drivers were originally specified for this one. I suspect you may have a response gap in the lower midrange/upper bass with what you now have. What most people think of as "bass" is really the middle to upper end of the bass region (100-250hz).

The original woofer on this probably was a wider range unit extended into those higher octaves (250hz+), at the expense of the mid to sub bass region. Your replacement subwoofer is probably tuned for the sub bass, and is probably rolling off too quickly before the midrange takes over.

Just a guess.

To show how you can take these things, here's a reworked Xover - before and after - for a classic era Klipsch 3-way that we use in our "beater" system. The layout is modest, but the parts are first-class. The caps are later covered with bluetack to "pot" them against internal resonances. The sonic improvement is profound:

Mine are very similar to those E-bay ones, except that they have the self-resetting fuses and the listing of that fact noted on the back of them as part of CV's verbage. I doubt that has any bearing on their performance however.

I'll definitely look at doing some rewiring. I have some binding posts here that I could use. The McIntosh gear of course all used those, as do both amps.

The range for the woofers (subs) that I'm using is 25Hz - 2,800Hz if that helps?

Nice work on that X-over BTW!

 

[SteveSRT8]

No good woof is going to cover 25-2800 hz. That's way too broad of a range for a physically large speaker IME.

We just cleaned out all our old large audio for a new modern setup. I'm tired of looking at big speakers, and they just aren't needed anymore.

Overkill, if you have a wooden suspended floor you may need to watch those monster subs as they can loosen the nails!!!

 

[OVERKILL]

Originally Posted By: SteveSRT8
No good woof is going to cover 25-2800 hz. That's way too broad of a range for a physically large speaker IME.

We just cleaned out all our old large audio for a new modern setup. I'm tired of looking at big speakers, and they just aren't needed anymore.

Overkill, if you have a wooden suspended floor you may need to watch those monster subs as they can loosen the nails!!!


That's the range given by the manufacturer? LOL