Planning phase for an higher end 2way

Will Brink

Will Brink

Junior Audioholic
Feedback/advice/thoughts

Hello all. After feedback on my prior posts, developing my thoughts on a prioject as DIY newbie. What follows is my general thoughts and goals for a project, and please add thought and Qs that further narrow it down. I'm in a general planning phase.


Goal: Not looking for a cheap experiment build, but something high(er) end that rivals, or exceeds my current reference speakers, ATC SCM 19s. That's a tall order I suspect, but if something I build/have built is as good, but half the $ or less say, that's goal achieved. I'd say 2k max budget, which is approx 50% of those ATC, but budget is not locked in stone, The real win would be producing something I enjoy even more...
Design: stand mount 2 way, mated with a sub (Velodyne HGS 12) in mid sized room.
Watching Toid's vids for example, I'm leaning toward Dayton Esoteric 7" Driver and Peerless Corundum tweeter. Or, perhaps Kartesian drivers? I want all top quality drivers there.
Power/X overs: I have always wanted active speakers as I feel actives are the future. Currently, thinking about the Hypex Fusion Amp FA122, which has DSP per members advice here. Other recs there? Would such an amp have the fidelity of a higher end build? I have no experience with class D amps, but I know they have come a long way and now accepted in "audiophile" circles now, at least by some. Power wise, while I don't listen to music at high SPL levels, I do want amplification with plenty of headroom and power to spare for a smoother more dynamic listening. That amp is Power (4Ω) 2x 125Wrms/Power (8Ω) 2x 75Wrms, but they do make another with more power.
Sound quality goals: A focus on resolution, vocals, mids/highs, without trying to force deep base from them. The sub will do say 80HZ and below, but that may change with how these speakers behave. Point being, not trying to get a 2 way stand mount to deliver full range audio per se.
I like clean forward sounding speakers, that don't get too bright either, not always an easy balance.
Cabinet wise, I like this design and would be interested in that scaled up in size for the above design goals. I'm sure a pre existing design already exists that could be followed, but I do like the idea of using real wood per vid vs MDF. I'd likley have someone with the carpentry skills and tools I don't have build it for me, and hopefully I can do the rest...



https://www.youtube.com/watch?v=xTeeMulW6cc
 
TLS Guy

TLS Guy

Seriously, I have no life.
Feedback/advice/thoughts

Hello all. After feedback on my prior posts, developing my thoughts on a prioject as DIY newbie. What follows is my general thoughts and goals for a project, and please add thought and Qs that further narrow it down. I'm in a general planning phase.


Goal: Not looking for a cheap experiment build, but something high(er) end that rivals, or exceeds my current reference speakers, ATC SCM 19s. That's a tall order I suspect, but if something I build/have built is as good, but half the $ or less say, that's goal achieved. I'd say 2k max budget, which is approx 50% of those ATC, but budget is not locked in stone, The real win would be producing something I enjoy even more...
Design: stand mount 2 way, mated with a sub (Velodyne HGS 12) in mid sized room.
Watching Toid's vids for example, I'm leaning toward Dayton Esoteric 7" Driver and Peerless Corundum tweeter. Or, perhaps Kartesian drivers? I want all top quality drivers there.
Power/X overs: I have always wanted active speakers as I feel actives are the future. Currently, thinking about the Hypex Fusion Amp FA122, which has DSP per members advice here. Other recs there? Would such an amp have the fidelity of a higher end build? I have no experience with class D amps, but I know they have come a long way and now accepted in "audiophile" circles now, at least by some. Power wise, while I don't listen to music at high SPL levels, I do want amplification with plenty of headroom and power to spare for a smoother more dynamic listening. That amp is Power (4Ω) 2x 125Wrms/Power (8Ω) 2x 75Wrms, but they do make another with more power.
Sound quality goals: A focus on resolution, vocals, mids/highs, without trying to force deep base from them. The sub will do say 80HZ and below, but that may change with how these speakers behave. Point being, not trying to get a 2 way stand mount to deliver full range audio per se.
I like clean forward sounding speakers, that don't get too bright either, not always an easy balance.
Cabinet wise, I like this design and would be interested in that scaled up in size for the above design goals. I'm sure a pre existing design already exists that could be followed, but I do like the idea of using real wood per vid vs MDF. I'd likley have someone with the carpentry skills and tools I don't have build it for me, and hopefully I can do the rest...



https://www.youtube.com/watch?v=xTeeMulW6cc
My first thought is why do you want to build a stand mounted speaker? This limits power especially in the high demand lower frequency bands. If you eliminate the stand you can add power and bass extension and still have the same floor footprint.

If you are going to build a small two way, then the advantages of an active design are limited, but add a lot of complexity to the design. One thing you have to think carefully about is protecting the tweeter which is fragile. You can't safely connect a tweeter directly to any amp, unless you have an endless supply of tweeters.

I think if you are going to look at a state of the art design, then you need to start modelling some state of the art drivers, from the likes of SEAS, Morel for instance and a number of others.

To build a really excellent speaker requires significant R & D and development.

What sort of output are you hoping to get from this speaker?
 
M

MrBoat

Audioholic Samurai
Some thoughts. Active, may indeed be the future, but remember that a good part of that is being perpetuated by marketers needing to double down, now that audio technology has essentially eaten itself out of house and home. Most of my original class a/b electronics lasted 30 years before needing major repairs. I have had somewhat of a difficult time getting my class D powered audio to last more than 5-7 years, and the obsoletion/disposability factor seems much more premature than ever. I end up having to buy duplicates of any specialty components in the event that they become NLA, which happens a lot now.

If you are looking to improve upon what you already have, then using it for any benchmark at all can be more confusing than it's worth. I'd be disappointed to end up with something that I had a hard time differentiating between, and positively, with what I already had. I have a lot of speakers. Some which are measurably better than others, but that I enjoy less. Some speakers I have cost under $200 for the parts, but they make me smile when I listen to them, and then laugh at myself for being such a cheap audio date at times.

I started to design speakers, but every known driver and tweeter that I came up with that were even remotely compatible, had at the very least, been discussed already around the net. Once I figured out how much the computer would be involved, the intrigue of design, left me. What could I achieve? I could come back in 3 months or so and show off yet one more relatively flat measuring speaker design and give credit to who? The software designer?

Real wood vs. engineered wood? Nobody will care but you when it comes right down to it. I have been a carpenter/woodworker for 45 years, alongside my other trades. I even built the wood boat I fish from. What drives my material selections are stability and longevity. A lot of humidity where I live can wreak havoc on solid wood unless I can manage to keep them in a constant state of climate control and provided the AC doesn't ever break down for more than a couple days.

My main speakers are MDF but with real wood veneer and neatly done. My subs are plywood, with the same cherry veneer. Do they look high end? I hope not. I was going for more of the well finished craftsman look. Something that was obviously finished with skill, but not overdone for my home. My mains and subs match, yet I mostly see the black baffles more than anything else until I go to dust them.
 
Swerd

Swerd

Audioholic Warlord
I do like the idea of using real wood per vid vs MDF
When building a wooden box with six sides, stick with MDF or plywood, and avoid using real wood. Real wood expands and contracts depending on the humidity in the air. In the winter, the air in your home is much drier than it is during the summer months. The wood will expand and contract each year.

Clever wood workers know how to mitigate problems that come from wood's expansion and shrinkage from changing humidity, but they can't eliminate them. Using kiln-dried wood won't help because that wood will still expand and shrink as the seasons change. Sealing all sides of the wood panels can help, but only so much. Often, solid wood can be assembled with joints that have some built-in room for expansion.

A speaker cabinet is essentially a six-sided box with sealed seams – whether it's a "sealed" or a "ported" speaker cabinet. The joints between the wooden panels must be glued air tight. They have no room for expansion. I've seen speaker cabinets made from real wood, where the panels cracked and split because of humidity. And yes, the wood was coated with a sealer on the inside and outside. It made no difference.

The video you linked ignored that problem. It was a small cabinet, and that may help with the humidity problem. But your project will involve larger cabinets.

Make this project doable and use MDF or plywood. Both have flat surfaces that allow veneering.
 
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TLS Guy

TLS Guy

Seriously, I have no life.
My first thought is why do you want to build a stand mounted speaker? This limits power especially in the high demand lower frequency bands. If you eliminate the stand you can add power and bass extension and still have the same floor footprint.

If you are going to build a small two way, then the advantages of an active design are limited, but add a lot of complexity to the design. One thing you have to think carefully about is protecting the tweeter which is fragile. You can't safely connect a tweeter directly to any amp, unless you have an endless supply of tweeters.

I think if you are going to look at a state of the art design, then you need to start modelling some state of the art drivers, from the likes of SEAS, Morel for instance and a number of others.

To build a really excellent speaker requires significant R & D and development.

What sort of output are you hoping to get from this speaker?
Some thoughts. Active, may indeed be the future, but remember that a good part of that is being perpetuated by marketers needing to double down, now that audio technology has essentially eaten itself out of house and home. Most of my original class a/b electronics lasted 30 years before needing major repairs. I have had somewhat of a difficult time getting my class D powered audio to last more than 5-7 years, and the obsoletion/disposability factor seems much more premature than ever. I end up having to buy duplicates of any specialty components in the event that they become NLA, which happens a lot now.

If you are looking to improve upon what you already have, then using it for any benchmark at all can be more confusing than it's worth. I'd be disappointed to end up with something that I had a hard time differentiating between, and positively, with what I already had. I have a lot of speakers. Some which are measurably better than others, but that I enjoy less. Some speakers I have cost under $200 for the parts, but they make me smile when I listen to them, and then laugh at myself for being such a cheap audio date at times.

I started to design speakers, but every known driver and tweeter that I came up with that were even remotely compatible, had at the very least, been discussed already around the net. Once I figured out how much the computer would be involved, the intrigue of design, left me. What could I achieve? I could come back in 3 months or so and show off yet one more relatively flat measuring speaker design and give credit to who? The software designer?

Real wood vs. engineered wood? Nobody will care but you when it comes right down to it. I have been a carpenter/woodworker for 45 years, alongside my other trades. I even built the wood boat I fish from. What drives my material selections are stability and longevity. A lot of humidity where I live can wreak havoc on solid wood unless I can manage to keep them in a constant state of climate control and provided the AC doesn't ever break down for more than a couple days.

My main speakers are MDF but with real wood veneer and neatly done. My subs are plywood, with the same cherry veneer. Do they look high end? I hope not. I was going for more of the well finished craftsman look. Something that was obviously finished with skill, but not overdone for my home. My mains and subs match, yet I mostly see the black baffles more than anything else until I go to dust them.
There is a lot of wisdom there.

I think especially for first build, he needs to design the speaker passive first. If he wants, he can convert to active later. I think part of the attraction for active, is the notion you can match any drivers you like. That is not true. The first, and one of the most important tasks in a speaker build, is driver selection. Get that wrong and nothing else will go right and the build will be a disaster.
 
Swerd

Swerd

Audioholic Warlord
You also didn't mention a cabinet design. For that ES180TiA-8 woofer, Parts Express suggests a sealed cabinet of 0.24 ft³ (F3 = 69 Hz), or a ported cabinet of 0.57 ft³ (F3 = 37 Hz). Considering that the outer diameter of that woofer's frame is about 7", that will require a cabinet where the front baffle is at least 8" or even 8½" wide. I'll let you do the arithmatic to decide the height and depth of the cabinet needed to achieve the desired interior volume. Each panel will be ¾" thick, so the outer cabinet width will be 1½" larger than the inner width. Same goes for the height and depth. You also have to make room for the tweeter and a port tube. Hint: It will be very difficult to mount that woofer and tweeter in a sealed cabinet of 0.24 ft³. Go for a ported cabinet.

I mentioned the cabinet design first because you cannot begin to consider the crossover without a test cabinet with your intended dimensions. It doesn't matter whether your crossover is passive or active, analog or digital, at speaker level or at pre-amp level. The outer width of the front baffle has a significant effect on the acoustic behavior of both woofer and tweeter. So you must tackle the crossover while the drivers are mounted on a cabinet with your intended dimensions. It can be an unfinished MDF or plywood test cabinet.

I'll mention the concepts "baffle step response" and "baffle step compensation" here. But they are complex to explain. I'll look for links that explain it better than I can. But, suffice to say that you can't begin to properly compensate for the woofer's baffle step response without measuring your woofer mounted in its proper cabinet. Whatever frequency response curves the manufacturer published won't help unless they were made with a cabinet with the same front baffle width.

When designing a crossover, you will have to measure just how high a frequency the woofer can go without loosing more than 3 dB response when a measuring microphone is 30° off axis. The woofer manufacturer may or may not show this data, but it was probably done with a large baffle board, a so-called infinite baffle. You need that data while the woofer is mounted in a cabinet with your dimensions.

The tweeter's performance must also be measured while mounted in your cabinet. There will be response dips caused by diffraction by the edges of the front baffle. The frequency and amount of diffraction loss varies with the distance between the tweeter's center and the cabinet's front edges. You have to know that before you can attempt designing a crossover. You can minimize the diffraction losses by rounding over those edges, or mounting the tweeter off-center instead of centered edge-to-edge. But you can't eliminate it.

All this requires that you have a speaker measurement rig, and know how to properly use it. Not a trivial undertaking. That's why you should seriously consider an existing speaker design (drivers, cabinet dimensions, and crossover) for your first DIY project instead of designing it from scratch.
 
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Swerd

Swerd

Audioholic Warlord
The tweeter's performance must also be measured while mounted in your cabinet. There will be response dips caused by diffraction by the edges of the front baffle. The frequency and amount of diffraction loss varies with the distance between the tweeter's center and the cabinet's front edges. You have to know that before you can attempt designing a crossover. You can minimize the diffraction losses by rounding over those edges, or mounting the tweeter off-center instead of centered edge-to-edge. But you can't eliminate it.
Here's an example of the diffraction caused by a tweeter/cabinet combination. Below is a measured frequency response of a 1" dome tweeter mounted in an 8" wide cabinet. It's a raw frequency response, without any proper high pass filter. (It does have a single capacitor to protect the tweeter from frequencies low enough to damage it.)

Below roughly 3,000 Hz there is a prominent dip & peak. All tweeters mounted in a box this width will have a similar profile. No tweeter can have a smooth roll off in response with cabinet baffle widths that are normally used. As the sound waves at those frequencies reach the edges of the baffle, some will be reflected back and either cancel or augment new waves originating at the tweeter itself. These “diffraction effects” also show up as slight dips at higher frequencies. But what’s important is that even excellent tweeters will not have a smooth natural roll off in the types of cabinet baffles that are normally used. This can be accounted for or corrected in the crossover. But first, you have to be able to measure what your tweeter does when mounted in your cabinet.

1669670410671.png
 
Swerd

Swerd

Audioholic Warlord
I'll mention the concepts "baffle step response" and "baffle step compensation" here. But they are complex to explain. I'll look for links that explain it better than I can.
Try reading these links on baffle step compensation (BSC). I hope at least one of them helps to understand this:
 
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annunaki

annunaki

Moderator
I would just do the Helios as an active speaker. They will allow you to play a bit deeper than 80hz, offer very high fidelity, and still will mate well with your sub for the lowest registers.
 
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