Time for another DIY Speaker project

[keith_correa]

Another option for glue, which I found out with the help of the owner of the above website is: https://mccoymart.com/buy/essr-bond-ms-40-600ml-high-modulus-sealant/
(I have a bottle of this glue in hand but yet to try out in an actual build) It is supposed to have similar properties as Weicon Flex.

Brilliant, this! Thanks much!

The author of the above website has found through an extensive set of experiments that such a CLD construction (along with appropriate cabinet inner wall lining and driver mounting methods all given in website) significantly reduces panel resonances in the midrange band and can make audible differences in performance.

In the build the mid is open back so not sure how much of a +ve impact the CLD will have. If you are in touch with "augerpro" - can you ask him if he thinks it's worth going the CLD route with an open back mid?

Complicated stuff this and may be beyond my capability. Any pointers who could do this in Mumbai?

Were you going to build the box yourself?

 

[Vineethkumar01]

In the build the mid is open back so not sure how much of a +ve impact the CLD will have. If you are in touch with "augerpro" - can you ask him if he thinks it's worth going the CLD route with an open back mid?

Sorry, I didn't know that an open back mid is used in this project.
In my 3 way study build thread on diyaudio, augerpro has given many good suggestions so far.
I will ask him about what he thinks about using CLD when an open back mid is used.

Thanks
Vineeth

 

[captrajesh]

If you are in touch with "augerpro" - can you ask him if he thinks it's worth going the CLD route with an open back mid?

What's open back mid? In this design, mid-woofer has its own enclosure I think. Correct me if I'm wrong.

Were you going to build the box yourself?

No. Someone else will do it sitting far away. Getting it done remotely by explaining is the complicated part. If someone is available locally, it can be done moch more easily I guess.

I will ask him about what he thinks about using CLD when an open back mid is used.

All inputs are welcome.

 

[keith_correa]

What's open back mid? In this design, mid-woofer has its own enclosure I think. Correct me if I'm wrong.

The mid has its own enclosure but that enclosure is open at the back (no back wall).

 

[captrajesh]

The mid has its own enclosure but that enclosure is open at the back (no back wall).

Ohh! Is that so (for the Statements)? My bad! I didn't notice.

 

[Vineethkumar01]

This was Augerpro's reply when I asked whether a CLD box and/or CLD bracing scheme has any use in a project like this one with open back mids.

"I think there would still be benefit. Even if the woofer operates below the primary panel resonances, and the mid is open, they both still transmit energy to the panels through the driver frame so the box panels will still re-radiate that energy if nothing is done about it."

 

[Kannan]

The mid has its own enclosure but that enclosure is open at the back (no back wall).

This prima facie does not seem to be a good approach.
If the rear of the mids opens into the main enclosure, then the back waves of the woofer will hit on the mid's cones and impact the sound.
I would suggest putting the mids in a fully sealed enclosure within the main enclosure.

 

[Vineethkumar01]

This prima facie does not seem to be a good approach.
If the rear of the mids opens into the main enclosure, then the back waves of the woofer will hit on the mid's cones and impact the sound.
I would suggest putting the mids in a fully sealed enclosure within the main enclosure.

HI
I don't think the mid enclosure opens to the woofer enclosure in these type of designs. Rather it opens to the outside of the speaker cabinet.
For absorbing the back waves of the mids, probably a back-open mid cabinet with certain dimensions filled with absorption material maybe used (instead of a typical closed box filled with stuffing). Jim Holtz and Curt Campbell probably know reallywell what they are doing

Here is a link to enclosure construction details:

http://www.speakerdesignworks.com/StatementMonitorDwgs.pdf

Here is a thread about a build of this particular speaker:

Finalizing Statement Monitor Build - Few Questions - Techtalk Speaker Building, Audio, Video Discussion Forum

Want a second or third opinion about your speaker cabinet design or other audio related problem? Post your question or comment on the Technical Discussion Board. Hundreds of technicians, engineers, and hobbyists, nationwide read and discuss electronics related questions each week. We welcome...

techtalk.parts-express.com

Thanks
Vineeth

 

[Kannan]

I don't think the mid enclosure opens to the woofer enclosure in these type of designs. Rather it opens to the outside of the speaker cabinet

This is fine and essentially an open baffle design.

 

[keith_correa]

HI
I don't think the mid enclosure opens to the woofer enclosure in these type of designs. Rather it opens to the outside of the speaker cabinet.

Yes, the mid enclosure extends all the way to the back of the cabinet and is open at the back of the larger cabinet enclosure.

Jim Holtz and Curt Campbell probably know reallywell what they are doing

They certainly do!

The mid enclosure could be sealed too but that would affect the voicing and probably wouldn't be the "Statements" any more.

This is fine and essentially an open baffle design.

Not really. The mid enclosure is tuned to be a Transmission Line.

 

[Kannan]

Not really. The mid enclosure is tuned to be a Transmission Line.

Understood and indeed a very interesting design. Palms are now itching....

 

[captrajesh]

"I think there would still be benefit. Even if the woofer operates below the primary panel resonances, and the mid is open, they both still transmit energy to the panels through the driver frame so the box panels will still re-radiate that energy if nothing is done about it."

Thought as much. Sounds logical as well. Does the midrange tunnel needs to be of CLD as well?

For absorbing the back waves of the mids, probably a back-open mid cabinet with certain dimensions filled with absorption material maybe used

There are no details as to what damping material and how much to use.

 

[Vineethkumar01]

Thought as much. Sounds logical as well. Does the midrange tunnel needs to be of CLD as well?

There are no details as to what damping material and how much to use.

Please take a look at this thread that I posted above.

Finalizing Statement Monitor Build - Few Questions - Techtalk Speaker Building, Audio, Video Discussion Forum

Want a second or third opinion about your speaker cabinet design or other audio related problem? Post your question or comment on the Technical Discussion Board. Hundreds of technicians, engineers, and hobbyists, nationwide read and discuss electronics related questions each week. We welcome...

techtalk.parts-express.com

Jim Holtz mentions some details regarding the damping material there, specifically in post number 28.

I think there is no harm in making the mid tunnels CLD as well, if possible. The idea is to dampen panel resonances, whose effects are more noticeable in the frequency range of 300 Hz to roughly 1500 Hz.

In a 3 way with a closed box mid, there could additional layer of absorption/ dissipation of energy due to the outer bigger box.

When I asked a similar question to Augerpro regarding my project, he told the full cabinet in a 3 way (with a closed-box mid though) could be made CLD. It is his opinion and he has not tested it specifically for 3 way speakers. I too have not tested all the above yet.

But in this case, since it is an open back mid and smaller box sizes, more audible effects maybe perceived my proper tuning using damping material in the mid tunnel.

 

[keith_correa]

There are no details as to what damping material and how much to use.

Please read the two floor standing Statements writeup too and don't limit your reading just to the Monitor writeup because the Monitors are an evolution of the floorstanders. It will give you more insight and reveal things that one/you may have assumed and will prevent much heartache later especially for the cabinet etc. From the floor standing Statements writeup, I quote:
"The transmission line enclosures are lined with 1" foam with the foam held back about 1 ½" or scalloped from the back of the W4 drivers."
This holds good for the Monitor too!

 

[captrajesh]

Some updates:
Due to logistic constraints, decided to go in for 19mm MDF boxes while baffle would have an additional layer 10-12mm MDF to make it thicker.

As for X-over, I've decided to go with passive one to begin with. Cost of X-over (with Benevi caps and HTR resistors) including sourcing components & making them is said to be 17k. The X-over maker is recommending making PCB which will add to the cost. If I go with electrolytic caps, cost would come down it appears.

Need your inputs here. Do the Benevis and HTRs suffice or is there some sonic benefits of going for exotic caps/ resistors? And what are the pros of adding PCBs.

 

[Vineethkumar01]

Some updates:
Due to logistic constraints, decided to go in for 19mm MDF boxes while baffle would have an additional layer 10-12mm MDF to make it thicker.

As for X-over, I've decided to go with passive one to begin with. Cost of X-over (with Benevi caps and HTR resistors) including sourcing components & making them is said to be 17k. The X-over maker is recommending making PCB which will add to the cost. If I go with electrolytic caps, cost would come down it appears.

Need your inputs here. Do the Benevis and HTRs suffice or is there some sonic benefits of going for exotic caps? And what are the pros of adding PCBs.

PCB-based crossovers are neat overall...
Also in the unlikely event that some components go bad, the neat layout might permit even the end user to replace components easily.
Other than that I don't see any advantages to going with a custom made PCB crossover.
Crossover components with stricter tolerance values in manufacturing will perform closer to the original design of the intended circuit.
More experienced FMs can help better with these aspects I guess specifically regarding brands of components.

 

[Hari Iyer]

Some updates:
Due to logistic constraints, decided to go in for 19mm MDF boxes while baffle would have an additional layer 10-12mm MDF to make it thicker.

As for X-over, I've decided to go with passive one to begin with. Cost of X-over (with Benevi caps and HTR resistors) including sourcing components & making them is said to be 17k. The X-over maker is recommending making PCB which will add to the cost. If I go with electrolytic caps, cost would come down it appears.

Need your inputs here. Do the Benevis and HTRs suffice or is there some sonic benefits of going for exotic caps/ resistors? And what are the pros of adding PCBs.

My suggestion that you choose EPCOS motor capacitor which are Metalized polypropylene type. You will be surprised by its quality and cost vis-a-vis Benevis

PCB-based crossovers are neat overall...
Also in the unlikely event that some components go bad, the neat layout might permit even the end user to replace components easily.
Other than that I don't see any advantages to going with a custom made PCB crossover.
Crossover components with stricter tolerance values in manufacturing will perform closer to the original design of the intended circuit.
More experienced FMs can help better with these aspects I guess specifically regarding brands of components.

PCB is recommended if you are building many not just a pair. I shall prefer point to point wiring which has better results over PCB type.

 

[captrajesh]

Speaker box construction in progress:

The beginning


The tunnel for mid-range driver


The box.


Chamfering of mid-range & woofer drivers


Countersink for the binding posts plate


Side bracings to support the tunnel.

More pics to follow.

 

[keith_correa]

Speaker box construction in progress:
View attachment 65276

Whats this? A brace?

 

[captrajesh]

Whats this? A brace?

Yes it is.

As per the design.

Edit:
The deal was to make fully finished cabinets but the idea of CLD is still lingering in my mind! Since it's already made of a thick 19mm MDF, will a 2-3mm outer Aluminium layer with a damper in between have the qualities of CLD cabinet?