CSS Criton 3TD-X Kit Speaker Review

[Rick Sykora]

The resistor in the woofer circuit damps the "knee" that can happen sometimes on woofer crossovers and reduces some output bump we would get in the summing around the woofer to mid crossover point. This is a fairly common practice in woofer circuits since you get this benefit and it can also sometimes help align the phase a bit better if needed.

The bypass cap is a notch circuit for the mid. The mid has a little bit of cone breakup, which doesn't impact the distortion but was not as low in output as we wanted with the second order filter. This help notch out the peak and provide a better overall rolloff for the mid.

Thanks for sharing the added clarifications. I have quoted my use of the word unusual as bypass caps are fairly common but are used for different reasons. Agree your crossover uses one purposefully whereas others use them for more questionable reasons. Have not seen the woofer resistor damper previously, so a novice would be even less likely to have encountered.

If a novice looks in the VituixCAD library, they can readily find the circuits for various filter topologies, notch filters or a passive L-Pad (as used in your tweeter circuit). They will not find when a bypass cap might help as a notch and would more likely add more components to construct a more typical notch filter. So would consider it a more advanced application despite its simplicity.

Find it refreshing that CSS is willing to openly publish and discuss your crossover designs. It does help beginners and encourage others to improve. It is much more in the spirit of DIY than others selling kits generally provide. 

 

[ThatSoundsGood]

As for the tweeter, I personally think that bringing that area down results in a sound that is a bit too dull because the off axis of the tweeter falls off very quickly in that area. The peaking is part of the natural response of the tweeter and not "tilted up" to achieve that result. We just choose not to filter it out because we think it is an overall negative impact to the sound. But I can only hear up to 16 kHz anyway so younger ears might feel a bit different.

I've worked with this tweeter in builds and I totally agree. That lift above 10K is not very audible and is actually helpful off-axis as it goes away quickly. While there is definitely some information up there in music, I don't find these frequencies make thing sound "bright". So, I also left that energy up top in my builds and it's totally fine.

 

[musicisair]

This speaker may be a better example crossover than any of the ones suggested earlier. All of the filters are simple second order.

The compact layout made it look more complex than it is. The only unusual parts are the .47 bypass cap and the resistor in the woofer circuit. Both have comparable impact on the FR just at different frequencies. Here is a simplified look that should help novices see more clearly...

View attachment 409954

If you play with shorting out inline components or opening others, you can see how they affect the overall response. By opening the individual drivers, you can isolate a particular driver and its crossover.

SPL Trace is useful but can also introduce some ugly artifacts if unchecked. Should always check to see how well the traced curve matches the source by simply adding the driver and connecting it straight to the source. Also check measurement footnotes as some drivers (notably tweeters) may be measured with a passive filter in place.

Grouping the filter patterns together is extra helpful.

Thanks for sharing the added clarifications. I have quoted my use of the word unusual as bypass caps are fairly common but are used for different reasons. Agree your crossover uses one purposefully whereas others use them for more questionable reasons. Have not seen the woofer resistor damper previously, so a novice would be even less likely to have encountered.

If a novice looks in the VituixCAD library, they can readily find the circuits for various filter topologies, notch filters or a passive L-Pad (as used in your tweeter circuit). They will not find when a bypass cap might help as a notch and would more likely add more components to construct a more typical notch filter. So would consider it a more advanced application despite its simplicity.

Find it refreshing that CSS is willing to openly publish and discuss your crossover designs. It does help beginners and encourage others to improve. It is much more in the spirit of DIY than others selling kits generally provide. 

Just bought a bunch of their drivers yesterday because of the open and technical discussions they're having here and on other forums, as well as help via email. Additionally, the fact they they sent their speakers in to Amir for testing is really awesome. Seems like a really great company to do business with.

If all works out with these initial builds I might build out a whole 7.x.4 home theater system with their drivers next year...just gotta learn how to design a cohesive shallower on/in-wall/ceiling speaker, I mean how hard can it be ? (as I've learned recently: it's going to come with quite the learning curve)

 

[a4eaudio]

Grouping the filter patterns together is extra helpful.

Just bought a bunch of their drivers yesterday because of the open and technical discussions they're having here and on other forums, as well as help via email. Additionally, the fact they they sent their speakers in to Amir for testing is really awesome. Seems like a really great company to do business with.

If all works out with these initial builds I might build out a whole 7.x.4 home theater system with their drivers next year...just gotta learn how to design a cohesive shallower on/in-wall/ceiling speaker, I mean how hard can it be ? (as I've learned recently: it's going to come with quite the learning curve)

They're raw drivers are excellent. Their Black Friday sale is really testing my will power.

 

[ThatSoundsGood]

They're raw drivers are excellent. Their Black Friday sale is really testing my will power.

I bought two more LDX tweeters and some passive radiators for the 10" sub. I couldn't resist. I don't even know what I'm going to do with them yet!

 

[Paweł L]

I definitely find it annoying if the tweeter doesn't have a steep drop off axis. Tweeters like the XT25 or the SB29RDC I'm ok with a little lift there. Broader dispersion in that region with a lift can stand out a lot more to me.

The 29RDC is so boring one can fall asleep - without some lift it the top end I couldn't listen to it. It just too damped and reserved in general.
I have modified 'version' of the old, or first generation of LD25X from two decades ago, but this one is by Mark Kravchenko who worked with the old CSS. Just the driver without faceplate and chamber, I use them in my car stereo. Definitely different character than SB tweeters, way more lively.

 

[Paweł L]

I just traced the curves using the SPL trace tool from their driver datasheets. I did it multiple times, trying to be as precise as physically possible (using the logarithmic seeing when appropriate). Maybe I still did something wrong.

I'll take a look at your project, and another close look at the FRD files I created tomorrow.

I looked at the frd's this evening, they look OK to me. Now I have a head scratcher. Unless the sensitivity of the LDW6 is higher than the one is the sims - 83dB just looks way too low and suspicious to me. I can see LDW7, but I can't the '6'. 90dogBones at 1m, 2.83V would make sense. With 6dB added to LDW6 things fall into places

 

[musicisair]

I looked at the frd's this evening, they look OK to me. Now I have a head scratcher. Unless the sensitivity of the LDW6 is higher than the one is the sims - 83dB just looks way too low and suspicious to me. I can see LDW7, but I can't the '6'. 90dogBones at 1m, 2.83V would make sense. With 6dB added to LDW6 things fall into places

Glad to hear I didn't screw up the traces (at least too badly). The LDW6 datasheet is an off angle photo, so the image needed some doctoring in Photoshop to get things lined up enough for tracing.

Your network's SPL looks so flat! Is this simulation using the diffraction traces I created?

Maybe @Kerry Armes can provide some insight on the curves, measurements, and specs of the LDW6 datasheet?

 

[Paweł L]

network's SPL looks so flat! Is this simulation using the diffraction traces I created?

This with the X-O from the CSS kit data you posted. Not bad for the simulation with only on axis frds. I should try the tower version, let see how things are going to look.
The z for mid and woofers were around -20 to -25mm behind the tweeter. Normally I would measure drivers separately (without crossover), the sum in phase and then out of phase. Once I have the drivers imported into CAD, I adjust the z axis so sums approximate the measurements. This most likely the most error free way of having the delays properly included in simulation, with 'min phase response box's checked.

 

[musicisair]

This with the X-O from the CSS kit data you posted. Not bad for the simulation with only on axis frds. I should try the tower version, let see how things are going to look.
The z for mid and woofers were around -20 to -25mm behind the tweeter. Normally I would measure drivers separately (without crossover), the sum in phase and then out of phase. Once I have the drivers imported into CAD, I adjust the z axis so sums approximate the measurements. This most likely the most error free way of having the delays properly included in simulation, with 'min phase response box's checked.

I would love to trying out this vcad project, if you don't mind sharing, of course.

 

[musicisair]

This with the X-O from the CSS kit data you posted. Not bad for the simulation with only on axis frds. I should try the tower version, let see how things are going to look.
The z for mid and woofers were around -20 to -25mm behind the tweeter. Normally I would measure drivers separately (without crossover), the sum in phase and then out of phase. Once I have the drivers imported into CAD, I adjust the z axis so sums approximate the measurements. This most likely the most error free way of having the delays properly included in simulation, with 'min phase response box's checked.

I think the tweeter in your screenshot is inverted from what is indicated on the schematic.

I also noticed the values are slightly tweaked from the schematic. Did you use the optimizer to do this (I couldn't figure out how to use the optimizer for the few minutes I tried).

 

[Paweł L]

I think the tweeter in your screenshot is inverted from what is indicated on the schematic.

I also noticed the values are slightly tweaked from the schematic. Did you use the optimizer to do this (I couldn't figure out how to use the optimizer for the few minutes I tried).

The mid is out of phase, woofs and tw with positive polarity. I think the connected values are as stock as in CSS schematic. I will post the zip when I find a bit of time. It's winter tire season changeover ZOO in our garage, plus all the repairs before the snowfall, so I'm death tired when I come back from work

 

[Rick Sykora]

Grouping the filter patterns together is extra helpful.

Just bought a bunch of their drivers yesterday because of the open and technical discussions they're having here and on other forums, as well as help via email. Additionally, the fact they they sent their speakers in to Amir for testing is really awesome. Seems like a really great company to do business with.

If all works out with these initial builds I might build out a whole 7.x.4 home theater system with their drivers next year...just gotta learn how to design a cohesive shallower on/in-wall/ceiling speaker, I mean how hard can it be ? (as I've learned recently: it's going to come with quite the learning curve)

If home theater is the target, would not be basing my design on the 3txd. Notably, in-wall cabinetry adds another challenge and you may not want (or need) to use a dual woofer, bass reflex speaker. Using active crossovers would also make the design effort much simpler and should yield a better result overall.

Are you planning in-wall subwoofers or will they be in-room? How big is the room?

 

[musicisair]

If home theater is the target, would not be basing my design on the 3txd. Notably, in-wall cabinetry adds another challenge and you may not want (or need) to use a dual woofer, bass reflex speaker. Using active crossovers would also make the design effort much simpler and should yield a better result overall.

Are you planning in-wall subwoofers or will they be in-room? How big is the room?

The room is 16x15ft, with 9ft ceilings.

Audio will be powered by a Denon x3800H (or maybe x4800H if I can find a great price on a gently used one). Haven't decided on getting a Dirac license or not.

The LCR will not be in (or on) wall, and the LR channels will be 1-2 feet away from the wall (practical for a home with kids, but not textbook ideal), the center will likely be very close to the wall.

Subwoofers will mostly likely be in-room, and I'll add appropriate room treatments where necessary.

Due to seating placement and my ideal listening position (about 2.5 feet from the rear wall), I'm considered lowering the height channels to around 7.5ft, as Atmos complains about having 4 height channels at 9 feet with the ILP so far back. I haven't researched the potential effect of ceiling reflections and hanging the height channels though.

The seats pretty much go from wall to wall (I've given up trying to make the side surrounds sound reasonable for those sitting near the side wall ), so wide dispersion is a goal - I might toe the 3TDXs out a bit, as my kids like to take the middle seats, leaving me against a wall.

I thought the 3TD-X line was a decent DIY option because of their wide horizontal directivity, and the center channel's W(MT)W layout should hopefully also offer wider horizontal directivity to match. I want to go DIY because my wife wants a particular look, and the ones she loves most either don't perform well, or would just cost too much.

Again, I have nearly zero real experience here, so I do appreciate your expertise! Thanks!

 

[Rick Sykora]

The room is 16x15ft, with 9ft ceilings.

Audio will be powered by a Denon x3800H (or maybe x4800H if I can find a great price on a gently used one). Haven't decided on getting a Dirac license or not.

The LCR will not be in (or on) wall, and the LR channels will be 1-2 feet away from the wall (practical for a home with kids, but not textbook ideal), the center will likely be very close to the wall.

Subwoofers will mostly likely be in-room, and I'll add appropriate room treatments where necessary.

Due to seating placement and my ideal listening position (about 2.5 feet from the rear wall), I'm considered lowering the height channels to around 7.5ft, as Atmos complains about having 4 height channels at 9 feet with the ILP so far back. I haven't researched the potential effect of ceiling reflections and hanging the height channels though.

The seats pretty much go from wall to wall (I've given up trying to make the side surrounds sound reasonable for those sitting near the side wall ), so wide dispersion is a goal - I might toe the 3TDXs out a bit, as my kids like to take the middle seats, leaving me against a wall.

I thought the 3TD-X line was a decent DIY option because of their wide horizontal directivity, and the center channel's W(MT)W layout should hopefully also offer wider horizontal directivity to match. I want to go DIY because my wife wants a particular look, and the ones she loves most either don't perform well, or would just cost too much.

Again, I have nearly zero real experience here, so I do appreciate your expertise! Thanks

Will help as I can but sure there are other members with more experience. One set of my home theater mains and subwoofer just moved to my son’s new home. My home theater is getting downsized but is in a comparably sized room as yours.

As it is a major project and this is a review thread, suggest you start your own thread. It keeps this thread on topic and will likely attract more assistance from those who are not interested in a kit speaker review.

P.S. Likely you do not need a big center ime. Integration can be tricky and have found smaller ones to offer more flexibility. Would not worry about matching surrounds much so can save some work by using finished units. Atmos is another matter and I have limited experience with it.

 

[Paweł L]

The room is 16x15ft, with 9ft ceilings.

Audio will be powered by a Denon x3800H (or maybe x4800H if I can find a great price on a gently used one). Haven't decided on getting a Dirac license or not.

The LCR will not be in (or on) wall, and the LR channels will be 1-2 feet away from the wall (practical for a home with kids, but not textbook ideal), the center will likely be very close to the wall.

Subwoofers will mostly likely be in-room, and I'll add appropriate room treatments where necessary.

Due to seating placement and my ideal listening position (about 2.5 feet from the rear wall), I'm considered lowering the height channels to around 7.5ft, as Atmos complains about having 4 height channels at 9 feet with the ILP so far back. I haven't researched the potential effect of ceiling reflections and hanging the height channels though.

The seats pretty much go from wall to wall (I've given up trying to make the side surrounds sound reasonable for those sitting near the side wall ), so wide dispersion is a goal - I might toe the 3TDXs out a bit, as my kids like to take the middle seats, leaving me against a wall.

I thought the 3TD-X line was a decent DIY option because of their wide horizontal directivity, and the center channel's W(MT)W layout should hopefully also offer wider horizontal directivity to match. I want to go DIY because my wife wants a particular look, and the ones she loves most either don't perform well, or would just cost too much.

Again, I have nearly zero real experience here, so I do appreciate your expertise! Thanks!

I understand the Center ch. is closed enclosure, so I little easier to deal with, however it still needs a bit space behind not sound overly warm. In worst case scenario some EQ should take care of it. The Mains - you can always convert the bass reflex to 'leaky port' by plugging the bass reflex port with foam. As long as the receiver will have adequate ventilation it should take care of load. Yeah, I agree with Rick that rear doesn't have to be matched with Mains.

 

[Rick Sykora]

If bothering to DIY, would design speakers that fit the target application. Stuffing the port of a large speaker is a mediocre compromise and a design failure imo. It is one thing if you own an existing speaker, and it needs a hack. Expending effort to build a design that does not work for the application is a waste. Getting the design right up front is a fundamental best practice in product development.

 

[musicisair]

If bothering to DIY, would design speakers that fit the target application. Stuffing the port of a large speaker is a mediocre compromise and a design failure imo. It is one thing if you love an existing speaker, and it needs a hack. Expending effort to build a design that does not work for the application is a waste. Getting the design right up front is a fundamental best practice in product development.

Some genuine questions: is the problem with using the 3TD-X for (my) home theater the proximity to the front wall? Is it room size? Is it that it will be supplemented with 2-4 dedicated subwoofers and that could cause issues somehow? Is it the space it'll consume? Just unnecessary? What would ideal front stage LR speaker measurements look like (have they been measured here), as thought the wide horizontal directivity would be ideal? Am I just asking all the wrong questions ?

I know KEF markets their towers for home theater front stage LR, and even include port bungs, too. Lots of other quality brands market their ported towers similarly. Obviously the 3TDX doesn't have quite the same engineering rigor as KEF and some of these others, but I really didn't think it would be bad idea to use the 3TDX in my LCR.

 

[Rick Sykora]

Some genuine questions: is the problem with using the 3TD-X for (my) home theater the proximity to the front wall? Is it room size? Is it that it will be supplemented with 2-4 dedicated subwoofers and that could cause issues somehow? Is it the space it'll consume? Just unnecessary? What would ideal front stage LR speaker measurements look like (have they been measured here), as thought the wide horizontal directivity would be ideal? Am I just asking all the wrong questions ?

I know KEF markets their towers for home theater front stage LR, and even include port bungs, too. Lots of other quality brands market their ported towers similarly. Obviously the 3TDX doesn't have quite the same engineering rigor as KEF and some of these others, but I really didn't think it would be bad idea to use the 3TDX in my LCR.

Good questions for your own design thread.

 

[musicisair]

Good questions for your own design thread.

I finally did it. I completely forgot to ask those same questions though.

DIY Home Theater based around CSS Criton 3TD-X + 3TD-XC (a build thread)

Hi! Complete noob to speaker design (and really the idea of "audio science" altogether) here. Ya'll have been amazing answering my (very naive) questions, so thank you! After derailing CSS Criton 3TD-X Kit Speaker Review for a bit it @Rick Sykora suggested I start my own thread on building a...

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