Paul Carmody's Tarkus

[aeroash]

The quest was for a “reasonably priced” published 3-way floorstander design, and the two that made the shortlist were Tarkus, and Troels Gravesen's SBA 861 PFCR.
Tarkus appears reasonably well received and considered a bargain considering the low cost. There aren't any real-world reviews for the SBA861, I couldn't find any. I'll save that design for another day, although it is a much less complicated cabinet to execute.

I also liked that the Takus design was flexible as long as the driver distance and the cabinet volume were maintained. The Wilson-esque design appealed to me the most, and I quickly learnt to use SketchUp to draft a mockup. I didn't muster the best sketch, but getting there.

Here's the draft: The outer shell will be 18mm MDF, and the bracing 12mm.



I have zero experience or knowledge to assemble the crossover. I shall try nonetheless. Anything I should know before I go ahead and purchase the drivers?

 

[rwnano]

The quest was for a published 3-way design, and the two that made the shortlist were Tarkus, and Troels Gravesen's SBA 861 PFCR.
Tarkus appears reasonably well received and considered a bargain considering the low cost. There aren't any real-world reviews for the SBA861, I couldn't find any. I'll save that design for another day, although it is a much less complicated cabinet to execute.

I also liked that the Takus design was flexible as long as the driver distance and the cabinet volume were maintained. The Wilson-esque design appealed to me the most, and I quickly learnt to use SketchUp to draft a mockup. I didn't muster the best sketch, but getting there.

Here's the draft: The outer shell will be 18mm MDF, and the bracing 12mm.

View attachment 76209

I have zero experience or knowledge to assemble the crossover. I shall try nonetheless. Anything I should know before I go ahead and purchase the drivers?

howabout this one BTW : https://meniscusaudio.com/product/philharmonic-audio-bmr-speaker-kit/

 

[arj]

Congratulations..this is a great step !

If possible do think of the Amp you will be using to drive this since amp speaker synergy is more important that the amp and speaker individually

Personally I might prefer Troels Graversens speaker due to its better sensitivity hence more Amp options including a DIY pass labs in the future. But am sure the Tarkus ( named after the album by Emersen Lake Palmers album ? ) , will be great especially if your listening choice is Rock.

 

[aeroash]

Congratulations..this is a great step !

If possible do think of the Amp you will be using to drive this since amp speaker synergy is more important that the amp and speaker individually

Personally I might prefer Troels Graversens speaker due to its better sensitivity hence more Amp options including a DIY pass labs in the future. But am sure the Tarkus ( named after the album by Emersen Lake Palmers album ? ) , will be great especially if your listening choice is Rock.

True that on the sensitivity. I’ll just have to wing it with a Sabaj A30a or a Crown.

Paul’s vision for this design is what did it for me, I.e make a speaker with strong mids, and that’s the region rock guitars reside, mostly. If all goes well, I’ll be more than excited to pump guitar heavy rock/metal of the 70s and 80s, loud!
The low cost of the drivers is definitely a big pull, considering this is my first floor-stander build.

 

[Analogous]

@aeroash, congratulations on starting this exciting journey.
I was wondering if while researching speaker designs you considered full range drivers as well?
With no cross overs the time alignment challenges and frequency overlap between multiple drivers (integration?) the sound of full range drivers is immediate, coherent and depending on the quality of the drivers, tonally rich too.
I think there are several that present a easy load for low or modestly powered amps. I think there are several FM who have gone this route and could share their experiences and opinions.
I look forward to regular updates on your build

 

[arj]

True that on the sensitivity. I’ll just have to wing it with a Sabaj A30a or a Crown.

Paul’s vision for this design is what did it for me, I.e make a speaker with strong mids, and that’s the region rock guitars reside, mostly. If all goes well, I’ll be more than excited to pump guitar heavy rock/metal of the 70s and 80s, loud!
The low cost of the drivers is definitely a big pull, considering this is my first floor-stander build.

Yes but try not to compromise on cost especially on the quality of components and wood. maybe cosmetics/Finishing can be done later as well. Cost of quality amplification in the future is also something to be considered hence my question.

But am sure you will love this speaker once you get the right drive !

 

[aeroash]

@aeroash, congratulations on starting this exciting journey.
I was wondering if while researching speaker designs you considered full range drivers as well?
With no cross overs the time alignment challenges and frequency overlap between multiple drivers (integration?) the sound of full range drivers is immediate, coherent and depending on the quality of the drivers, tonally rich too.
I think there are several that present a easy load for low or modestly powered amps. I think there are several FM who have gone this route and could share their experiences and opinions.
I look forward to regular updates on your build

Widebanders make a compelling case. I sampled one with a Lii Audio F15, but it was an OB. https://www.hifivision.com/threads/the-betsy-baffle-project.90790/

Tarcus already has all the plans outlined, including the crossover schematics, hence minimal risks. My quest was specifically for a 3 way, no particular reason, really,

This a pet project to get my juices flowing. I'm not looking to replace my main system. I'm also not looking for anything highly resolving or detail-oriented. For that, one day, I would be looking at the SB Acoustics beryllium or the TexTreme drivers.

 

[Analogous]

Widebanders make a compelling case. I sampled one with a Lii Audio F15, but it was an OB. https://www.hifivision.com/threads/the-betsy-baffle-project.90790/

Tarcus already has all the plans outlined, including the crossover schematics, hence minimal risks. My quest was specifically for a 3 way, no particular reason, really,

This a pet project to get my juices flowing. I'm not looking to replace my main system. I'm also not looking for anything highly resolving or detail-oriented. For that, one day, I would be looking at the SB Acoustics beryllium or the TexTreme drivers.

You are way ahead brother!
Hadn’t seen this thread. The OBs must sound great.
On with the quest…..

 

[Yelamanchili manohar]

The quest was for a “reasonably priced” published 3-way floorstander design, and the two that made the shortlist were Tarkus, and Troels Gravesen's SBA 861 PFCR.
Tarkus appears reasonably well received and considered a bargain considering the low cost. There aren't any real-world reviews for the SBA861, I couldn't find any. I'll save that design for another day, although it is a much less complicated cabinet to execute.

I also liked that the Takus design was flexible as long as the driver distance and the cabinet volume were maintained. The Wilson-esque design appealed to me the most, and I quickly learnt to use SketchUp to draft a mockup. I didn't muster the best sketch, but getting there.

Here's the draft: The outer shell will be 18mm MDF, and the bracing 12mm.

View attachment 76209

I have zero experience or knowledge to assemble the crossover. I shall try nonetheless. Anything I should know before I go ahead and purchase the drivers?

Excellent looking @aeroash.. Already got my juices flowing

Since you seem open to suggestions, below are the few I can think of : (without altering the basic design)

1. Make the front baffle 50mm. This is the area that bears the brunt of the drivers. The thicker and more inert it is, lesser will be the cabinet colouration.
2. The design inherently allows for a sealed cab, albeit shared between the mids and the tweeter. Maybe you can consider a sealed chamber for the tweeter too. And please do stuff a generous amount of lambs wool behind the drivers.
3. This will need a lot of additional cabling but is worth the effort. Have individual binding posts for each driver at the back of the cabinet. And keep the crossover in an external box. This will give you the future flexibility to go active if you want.
4. If the speaker is not as sensitive as you would like, then since the crossover is external, you can have two sets of inputs. One for the bass driver and one for the mids / treble. This will give you the option to use SS, amps for bass, and tubes for mid / treble.
5. If I was building my speakers again, I would chop it up into 3 different sections. The bass, mid and treble cabinets. This would give the option of using isolation between the individual cabs to isolate the drivers from vibrations caused by the other drivers.
6. I would glue a nice thick "mass loaded vinyl sheet" and additionally staple it to the inside of the front baffle. Especially for the bass driver area to damp the panel vibrations caused by the bass driver.
7. If you can make the front baffle 50mm. This will provide enough thickness of panel material to add a nice camper to the edges to reduce diffraction.

Please note that I know absolutely nothing about designing or building speakers. So all my above suggestions are only general in nature.

All the best for the build, and please keep us all posted on the progress of the build

 

[aeroash]

1. Make the front baffle 50mm. This is the area that bears the brunt of the drivers. The thicker and more inert it is, lesser will be the cabinet colouration.

Yes, I was thinking of doubling up on the front to make it 36mm. The woofer cabinet will be significantly braced and will tie up all the walls together nicely.

2. The design inherently allows for a sealed cab, albeit shared between the mids and the tweeter. Maybe you can consider a sealed chamber for the tweeter too. And please do stuff a generous amount of lambs wool behind the drivers.
3. This will need a lot of additional cabling but is worth the effort. Have individual binding posts for each driver at the back of the cabinet. And keep the crossover in an external box. This will give you the future flexibility to go active if you want.

The crossover will be on the floor of the woofer cabinet affixed on a removable plate, from underneath, when necessary. This should give me enough flexibility if a need arises. I have to make sure that I have a tight seal on the removable plate.

4. If the speaker is not as sensitive as you would like, then since the crossover is external, you can have two sets of inputs. One for the bass driver and one for the mids / treble. This will give you the option to use SS, amps for bass, and tubes for mid / treble.

This is a great suggestion! in this case I'll have to split the crossover, fodder for thought.

5. If I was building my speakers again, I would chop it up into 3 different sections. The bass, mid and treble cabinets. This would give the option of using isolation between the individual cabs to isolate the drivers from vibrations caused by the other drivers.
6. I would glue a nice thick "mass loaded vinyl sheet" and additionally staple it to the inside of the front baffle. Especially for the bass driver area to damp the panel vibrations caused by the bass driver.

Interestingly, Paul Carmody says this:
"The Woofer cabinet is lined with convoluted "eggcrate" foam, and does not have any stuffing or polyfil. The woofer cabinet will need a decent amount of bracing to tie the walls together, both from side-to-side and back-to-front. The TM cabinet will probably only need one simple brace; perhaps a piece of scrap 3" wide, tying the side walls together."

7. If you can make the front baffle 50mm. This will provide enough thickness of panel material to add a nice camper to the edges to reduce diffraction.

Do you mean Chamfer? I love chamfered edges. Let's see.

Please note that I know absolutely nothing about designing or building speakers. So all my above suggestions are only general in nature.

All suggestions are welcome! You have already made invaluable points! Much appreciated.

All the best for the build, and please keep us all posted on the progress of the build

Thanks!

 

[Yelamanchili manohar]

Yeah I was referring to chamfer .

 

[aeroash]

While I wait for the drivers to reach me, I made a few adjustments to the drawing so that I could hit the target volumes for both bins.

The gross volume for the TM cabinet is 13.36L, and 65.79L for the Bass cab.

My shoddy math skills showed me that I was low on volume because of the doubling of the front baffle on the Bass cab (18 mm+18 mm).
I did not want to go deeper as that would ruin the nice lines. There was just about enough space in the TM cab and used it to my advantage to push the bass cab volume upwards. The horizontal blue line you see below is where the bass cab will end.

 

[Analogous]

While I wait for the drivers to reach me, I made a few adjustments to the drawing so that I could hit the target volumes for both bins.

The gross volume for the TM cabinet is 13.36L, and 65.79L for the Bass cab.

My shoddy math skills showed me that I was low on volume because of the doubling of the front baffle on the Bass cab (18 mm+18 mm).
I did not want to go deeper as that would ruin the nice lines. There was just about enough space in the TM cab and used it to my advantage to push the bass cab volume upwards. The horizontal blue line you see below is where the bass cab will end.



View attachment 76261


View attachment 76262

Elegant and visually pleasing proportions!

 

[aeroash]

Update:

I had forgotten to take the wall thickness into consideration for one of the sides, and that screwed up the total volume a bit. I had to redraw to accommodate the same.

I decided against using MDF because the mitre bevels and angles of this trapezoid would be a challenge to use F clamps. I prefer plywood if using screws and hence went with ply. Here's the rough cut, I still have to cut a few more bevels at the top.

As Confucius says, always cut first, then measure, it's the only way to keep buying more plywood!

 

[Analogous]

Those sculptures in the background look nice too. How about sharing some of your other artwork too ?

 

[aeroash]

Setback!
I finished cutting the braces and realised that I could not proceed without the Flare Port. Audiocrafts is taking its own sweet time to process the goods.

Question: Can anyone help me find Egg Crate Foam, to line the bass cabinet? or are Felt Sheets ok?

Here's Troels take on damping, if anyone is up for a quick read.

Cabinet-damping

 

[jmascreen]

Setback!
I finished cutting the braces and realised that I could not proceed without the Flare Port. Audiocrafts is taking its own sweet time to process the goods.

Question: Can anyone help me find Egg Crate Foam, to line the bass cabinet? or are Felt Sheets ok?

Here's Troels take on damping, if anyone is up for a quick read.

Cabinet-damping

there are some available on amazon.in

 

[aeroash]

there are some available on amazon.in

 

[jmascreen]

You can check the build logs of others

 

[Analogous]

Setback!
I finished cutting the braces and realised that I could not proceed without the Flare Port. Audiocrafts is taking its own sweet time to process the goods.

Question: Can anyone help me find Egg Crate Foam, to line the bass cabinet? or are Felt Sheets ok?

Here's Troels take on damping, if anyone is up for a quick read.

Cabinet-damping

https://www.amazon.in/YGM-Acoustic-Foams%C2%AE-Sheet-Soundproofing/dp/B08GCHM9HH/ref=asc_df_B08GCHM9HH/?tag=googleshopdes-21&linkCode=df0&hvadid=434900838375&hvpos=&hvnetw=g&hvrand=4178801661695587436&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1007768&hvtargid=pla-951376956429&psc=1&ext_vrnc=hi

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