4 ways active floor standing project

[stonemarten]

Experts,

I’m trying to build a high end floor standing speakers (plus a central later), and I’m not sure I’m on the right direction… I’ve studied a lot, with the only result to make me more confused…

I found your forum very inspiring, and I hope you can share your experience with me

What I want to do: 2 floorstanding speakers (+ 1 central later) with the most natural sound possible. I want seat and listen the real instruments and voices, nothing too “cold” (like the B&W speakers under 5k USD i.e.) or too flat. Here the draft for the floorstanding. The central will be a match later.
I need a speaker that “rock” as well, because I listen electro and rock at high volume sometimes…
My amp now is a Marantz SR7002, that could be used as pre-amp or direct with 150W per channel.
For the design I have the maximum flexibility, so feel free to make any recommendations. I’m thinking to drill the angled panels for use better the cabinet volume (dimensions in mm).

Here my (many ) questions:

1. What do you think about the drivers choice?
a. Scan Speak r3004-662000D
b. Scan Speak 15m-4531k00
c. Scan Speak 18w-4531g01
d. Scan Speak 18wu-4747t00
Is a 4 ways too much (I want cover as much as I can the frequencies)? Are there drivers with same quality for less price, or better quality for a small price increase? Can I have the same result with 3 drivers?
2. Crossover: I’m thinking to make the speakers active, using the miniDSP (1x4 or 2x8?) and the miniDSP mic for measurements. Is that a good idea? Is perhaps better passive (but looks like the design is complicated and more expensive) ? my amp can bi-amp, so in theory possible..
3. What I can use for amp the drivers? I read some good review about the ICEPower but looks like it is too cold and difficult to get. I would have a “one button all on” system. I think I can even buy something Yamaha HI-FI base amp for every 2 drivers (like tweeter on left channel and mid on right, etc.) but they are big, heavy and I can only put them at the bottom of the speakers… still don’t know if that make sense. Or car amps with audiophile spec, if they exist at reasonable price? i.e., how I define the volume of the various amps in case of amp module without volume pot? Adding a pot is always possible?
What about Hypex UcD180HG with HxR?
4. What’s the best frequency cut for the drivers, or what’s the best way to define?
5. What’s the best filter for the crossover? Looks like it’s the linkwitz, but again not sure
6. In my case, is better 4 ohm or 8 ohm speakers?
7. I downloaded the scans speak toolbox: below the results, but not sure how to use properly for my project
8. If I go active, do I need to protect the tweeter with a 10 microfarad resistance in series?
9. Is better amps with thermal protection right?
10. If I leave always the amps on, are the drivers go to overheating?
11. If I buy the amp card, for ground them is an aluminium frame enough?
12. I want put some “cone” like in the anechoic chamber on the angled panels and compressed wool between that panels and the vertical/horizontal one: do you have better recommendation?
Bitumen sheet on all the internal walls
13. What do you recommend for cabinet wood material? MDF is good enough or plywood is better? Now is 15mm but I can make ticker.
14. I plan to cut the front panel in the between of “driver box” for avoid vibrations: is that a good idea or a waste of time?

I listened a lot of speakers in the shops, some VERY expensive (>10k USD a piece), and 90% of them are really not close to reality IMHO; looks like they are trying too hard to get us say “listen the violin” or “listen that voices”, forgetting that their scope is report the sound as in a natural environment

For your information, I live in Japan.

Thanks in advance for your great help and I hope my post is not too messy…

 

[GranteedEV]

Sorry if my answers are brief - it's late and you asked a LOT of questions. Feel free to ask me to elaborate if something confuses you.

What I want to do: 2 floorstanding speakers (+ 1 central later) with the most natural sound possible. I want seat and listen the real instruments and voices, nothing too “cold” (like the B&W speakers under 5k USD i.e.) or too flat.

With due respect, the transducers and the signal chain should be flat. If you want euphonic EQ, by all means use euphonic EQ. Don't try to build that into the system as a stock feature.

NwAvGuy: What We Hear

Now if by flat you weren't talking about frequency response, but soundstage depth, then yes, I know what you mean. Speakers that image well will give you a deep 3D soundstage. That's different from tonality though.

1. What do you think about the drivers choice?
a. Scan Speak r3004-662000D
b. Scan Speak 15m-4531k00
c. Scan Speak 18w-4531g01
d. Scan Speak 18wu-4747t00
Is a 4 ways too much (I want cover as much as I can the frequencies)? Are there drivers with same quality for less price, or better quality for a small price increase? Can I have the same result with 3 drivers?

I think that not only is the 4-way very convoluted, a single 7" midwoofer as the bass section is a total waste, no matter how high-end. It simply doesn't have the swept volume for a true crescendo.

Beyond that, I'm not sure you really need to spend that much money to get what you want.

Have you ever built your own speakers in the first place? If not, perhaps the prudent thing to do would be to get a hang of that in-and-of-itself, with less expensive drivers. A simple two-way would be best. In fact I'm not even sure you need to start from scratch - there are many interesting, existing DIY designs out there the likes of which may satisfy you immensely. Some with much more affordable drivers.

Have you considered that multiple, well-placed subwoofers will ensure even frequency response in the bass better than freestanding towers placed for optimal stereo imaging? If not, perhaps you ought to consider a system designed to mate to multiple subwoofers.

2. Crossover: I’m thinking to make the speakers active, using the miniDSP (1x4 or 2x8?) and the miniDSP mic for measurements. Is that a good idea? Is perhaps better passive (but looks like the design is complicated and more expensive) ? my amp can bi-amp, so in theory possible..

Active can have its benefits, though they may be over-stated.

3. What I can use for amp the drivers? I read some good review about the ICEPower but looks like it is too cold and difficult to get. I would have a “one button all on” system. I think I can even buy something Yamaha HI-FI base amp for every 2 drivers (like tweeter on left channel and mid on right, etc.) but they are big, heavy and I can only put them at the bottom of the speakers… still don’t know if that make sense. Or car amps with audiophile spec, if they exist at reasonable price? i.e., how I define the volume of the various amps in case of amp module without volume pot? Adding a pot is always possible?

A few suggestions:
XLS DriveCore Series
Amplifier Kits
ATI AT1805 Five Channel x 180 Watt Amplifier - B-Stock (120V) - Amplifiers
https://emotiva.com/products/amplifiers/xpa-5
http://chipamp.com/product/non-inverting-lm3886-stereo-amplifier-kit/

What about Hypex UcD180HG with HxR?

Hypex amps are also good, and could be a fun project if you're interested. But realize that amps, and electronics in general, may only be 5% of "what you hear" - if that. Don't dwell on them as even poor electronics are often one of the strongest links. The speakers, their interaction with the room, and the room itself are going to be a much more significant factor. Have you considered QRD panels for example? Bass traps? Because those will make a much more immediate difference than even those shiny hypex ncores compared to a cheap T-amp.

4. What’s the best frequency cut for the drivers, or what’s the best way to define?

There's a lot of factors that go into this, and I really can't just compress it into a simple post. Consider off-axis frequency response, power handling (excursion-limited AND thermal-limited), and natural driver rolloffs. Beyond that there's also a driver tendancy to want certain crossover points due to the differences in their acoustic centers.

5. What’s the best filter for the crossover? Looks like it’s the linkwitz, but again not sure

The best filter is... whatever will get you your desired acoustic response. It probably won't be symmetrical, it probably won't look anything like a textbook filter, any of that stuff. And so what's your desired acoustic response? anything that integrates the drivers well both on-axis and off-axis. I like to think of there as being two practical crossover types: in-phase and phase-quadrature - and everything in between is simply an imperfect variation. The rest - linkwitz-riley, bessel, butterworth, chebychev, duelund, cauer-elliptic... they're all just applications of these two basic ideas.

Both have their pros and cons and neither is inherently superior, but in-phase crossovers are probably less sensitive to inter-driver phase tracking, simply because even if they're not summing ideally, they're still summing well.

1. In my case, is better 4 ohm or 8 ohm speakers?

It really doesn't matter for active. Efficiency does not change between 4 ohm or 8 ohm drivers - only sensitivity. For passive crossovers, it's a matter of being careful - both can be beneficial in a given application.

8. If I go active, do I need to protect the tweeter with a 10 microfarad resistance in series?

I would probably try to save amps, and only have one active crossover in the lower mids / upper bass, allowing the mid-tweeter crossover to be passive. No point wasting a whole amp on just a tweeter.

9. Is better amps with thermal protection right?

?

10. If I leave always the amps on, are the drivers go to overheating?

If the amps are on, but there is no signal being fed to them, the drivers will easily stay cool.

11. If I buy the amp card, for ground them is an aluminium frame enough?

Yes. Grounding to the chassis is best.

12. I want put some “cone” like in the anechoic chamber on the angled panels and compressed wool between that panels and the vertical/horizontal one: do you have better recommendation?
Bitumen sheet on all the intern[l walls

Insulation.

13. What do you recommend for cabinet wood material? MDF is good enough or plywood is better? Now is 15mm but I can make ticker.

Neither is "better" as a panel. Both have their pros and cons although once you've braced well, it won't particularily matter.

14. I plan to cut the front panel in the between of “driver box” for avoid vibrations: is that a good idea or a waste of time?

I don't think it's particularily worthwhile, although if the speaker starts to get too large, it can make it more managable from a practicality perspective.

 

[stonemarten]

GranteedEV,

thanks very much for the time you spent to answer, really appreciated!!

Now if by flat you weren't talking about frequency response, but soundstage depth, then yes, I know what you mean. Speakers that image well will give you a deep 3D soundstage. That's different from tonality though.

Yes, this is what I mean, something that reproduce the reality as much as possible.

I think that not only is the 4-way very convoluted, a single 7" midwoofer as the bass section is a total waste, no matter how high-end. It simply doesn't have the swept volume for a true crescendo.

What about replacing the midwoofer and the woofer with a single one, like the 26W/8867T00? My amp can bi-amp: can I perhaps run that driver directly or do I break everything, or lose control?
One driver is enough or do I need 2?

Have you ever built your own speakers in the first place?

Yes, this is my project #6. For all the others, I used high end 3-way car kits (with XO), with pretty good results. What I want to do is move to the next step

Have you considered that multiple, well-placed subwoofers will ensure even frequency response in the bass better than freestanding towers placed for optimal stereo imaging?

I have 2 Yamaha active subs now, positioned with the rule "put your sub in your listening point and move yourself around the room until you find the best sound"

Question 3

The XLS drive core looks very good, as quality and price. I don't understand one thing: can they act as a crossover? Do I still need the MiniDSP?
The XLS are much more powerful than the drivers: how can I protect them? Is possible to set a "power cap"?

Have you considered QRD panels for example? Bass traps?

I've considered bass traps

Question 8

I understand your point. My idea starts after reading the excellent material on Mr. Elliot website. I have no ability to create a passive XO. I know is a waste for the tweeter but I prefer to stay safe and run them with a separate amp.
Is that 10 micro farad resistance a good idea or do you have any better recommendation?

Question 9

If I buy a commercial amp like the XLS is there already

Do you think that the volume inside the "driver box" is sufficient? Of course, if I move to 1 woofer instead of the 1 midw + 1 woofer I can use all the space.

For the matching central, can I cover it with the tweeter and 2 mids only or do I need to add the woofer as well (basically making 3 identical speakers - left, central and right)?

You are really helping me to dissolve all the fog in my mind!!

 

[stonemarten]

Btw, I've just finish to read the "what we hear" article and I'm still laughing!!
I grew up in a wine area, and can't agree more with all the "experts" that judge a bottle from the sticker...
Same for cars and audio

Thanks for sharing!

 

[GranteedEV]

What about replacing the midwoofer and the woofer with a single one, like the 26W/8867T00? My amp can bi-amp: can I perhaps run that driver directly or do I break everything, or lose control?

Lose control over what? I'm simply not following you.

One driver is enough or do I need 2?

That's a good question, and the answer is neither yes nor no. It depends on your budget, your ability to integrate two drivers together, your driver sizes, etc. I would say that two bass drivers has an advantage in terms of the floor/ceiling in-room interaction, but it has some disadvantages in terms of crossing over to a midrange. Since you've got multiple subs already, I would start with a single 10" woofer - one which does not require ports to hit an F3 under 100hz.

I have 2 Yamaha active subs now, positioned with the rule "put your sub in your listening point and move yourself around the room until you find the best sound"

Have you actually measured the results in-room?

The XLS drive core looks very good, as quality and price. I don't understand one thing: can they act as a crossover? Do I still need the MiniDSP?

The "crossovers" on those amps are very insufficient due to their fixed and symmetrical nature. I would not advise you to have any expectations of them.

The MiniDSP isn't the only active crossover out there, but it's a unit I like. With software like LSPCad and ACD, you can extract biquad values that let you import a crossover immediately.

In general you will want something that lets you select different poles, different slope filters, and parametric EQ as well. The miniDSP has the power to do it, as do a few other pieces like the DBX Driverack.

If you want something a bit higher-end, the Hypex PSC2.4 is a nice piece.

The XLS are much more powerful than the drivers: how can I protect them? Is possible to set a "power cap"?

You can set a power cap by being sensible with the volume dial ;P

I've considered bass traps

Consider both QRD panels and bass traps to be more massive contributors to final sound than electronics.

I understand your point. My idea starts after reading the excellent material on Mr. Elliot website. I have no ability to create a passive XO. I know is a waste for the tweeter but I prefer to stay safe and run them with a separate amp.
Is that 10 micro farad resistance a good idea or do you have any better recommendation?

Rod Elliot's site has some good information, but is pretty biased in his own way. 10uF is going to roll you you off too early to be useful either way for a so-called active crossover (sounds more like passive bi-amping). 10uF on, say, a 6 ohm tweeter will start an electrical rolloff around 2.6khz. Unless that value actually helps give you the rolloff you want, it's pretty pointless in my opinion. If you insist on running a tweeter directly to an amp, a 500uF or greater cap should protect it from potential DC thump. This will still induce a phase shift that needs to be factored into system design. Like I said earlier though, I highly recommend going passive on the mid/tweeter crossover.

My opinion, is that if you don't have the confidence or knowledge to make a passive crossover, then you're probably inable to make an active one either. They're essentially two sides of the same coin, and active is not a substitute for good crossover design, nor will passive impede that.

What you will need for sure either way is a measurement microphone setup, like the calibrated ones from cross-spectrum labs.

To incorporate passive crossovers into that, you simply need a method of measuring electrical impedance. The easiest of which is a woofer tester like the Dayton DATS or Smith and Larson WT2. I really think you should give a passive mid/tweeter section consideration. In my opinion it's the more elegant solution for a system to have hybrid active/passive crossovers.

Do you think that the volume inside the "driver box" is sufficient? Of course, if I move to 1 woofer instead of the 1 midw + 1 woofer I can use all the space.

Sufficient "for what end?" is the question.

For the matching central, can I cover it with the tweeter and 2 mids only or do I need to add the woofer as well (basically making 3 identical speakers - left, central and right)?

Horizontal MTM centers are unideal. That doesn't mean All three front speakers have to be identical though. Let's not even have that topic in mind. Focus on the task-at-hand.

 

[stonemarten]

GranteedEV,

Lose control over what? I'm simply not following you.

I mean over the crossover point and the overall system balance. My amp doesn't have any control of the bi-amp section.

Have you actually measured the results in-room?

Only using the Audissey amp set up... I'm planning to do that once I have the calibrated mic.

Horizontal MTM centers are unideal. That doesn't mean All three front speakers have to be identical though. Let's not even have that topic in mind. Focus on the task-at-hand.

got it Will focus on that later.

I think I have enough information for start the project: please give me some time to digest and modify my initial draft and I will post again the progress, hopefully with not too many questions again

 

[GranteedEV]

I mean over the crossover point and the overall system balance. My amp doesn't have any control of the bi-amp section.

Are you referring to the amp channels on the Marantz SR7002? You can't use them to properly bi-amp, unless you wish to use the surround channels on the tweeters instead, which is a bit of a waste of such a fine reciever.

 

[BoredSysAdmin]

Dear StoneMaren - I tried to follow your question to guess your level of proficiency in audio design and my gut feeling tells me what you still have a LONG way to go before designing speakers OR crossovers.

Here is my two suggestion

Option A)
Easiest option - get a speaker kit and learn how to build it and how it sounds like - it could be something like this :
TriTrix MTM TL Speaker Components And Cabinet Kit Pair
Designed by Curt Campbell it will not disappoint and very easy to build

Even if you add shipping to Japan, it still would be high value/quality speaker to be proud of

Option B) a bit harder, yet more rewarding. We are lucky to have TWO VERY experienced and talanted audio designers share this amazing speaker design with all of us.
It's called ER18 and I guarantee you - It would sound much better than anything you semi-randomly put together - sorry if you feel offended by this.
Here is the link to the design and project: Feel free to start your own build thread here and ask question from people who built theirs

http://forums.audioholics.com/forums/diy-corner-tips-techniques/68531-new-diy-mtm-towers-designed-dennis-murphy-paul-kittinger.html
Kit / DIY Main Speaker - AVS Forum

 

[lsiberian]

I have 3-way active speakers using a Minidsp and a Sure 4x100 chip amp for each speaker so it's certainly a doable task. You could use any drivers you want I suppose for a speaker with an Active design. a 4-way should have a sub as the bottom not a traditional woofer.

Did you have any idea what type of design you were aiming for? Sealed, Ported, Open-Baffle, TL, Horn? You could certainly do any of them. Sealed is probably the simplest. Do you have an overall budget? Do you have woodworking capabilities already?

Right now you are in the question phase of the project IMO. You shouldn't commit to do anything until you have a chance to review the options and decide what sounds like fun to you.

I find using a pre-existing design to be a good introduction to the construction techniques. If you really want to go 3-way for your first project I suggest you use the Dayton Dome Midrange it has excellent response from 5khz to 500hz. You'd just need a good woofer and tweeter. You'd only need a chamber for the woofers.

 

[crossedover]

This would be a fun first build. https://www.madisoundspeakerstore.com/2.5-way-speaker-kits/uluwatu-sb-acoustics-tower-speaker-kit-pair/ great price good design and fun to cut your teeth on

 

[stonemarten]

lsiberian,
thanks for the comments

I have 3-way active speakers using a Minidsp

What model are you using?

a 4-way should have a sub as the bottom not a traditional woofer

Got it

Did you have any idea what type of design you were aiming for? Sealed, Ported, Open-Baffle, TL, Horn? You could certainly do any of them. Sealed is probably the simplest. Do you have an overall budget? Do you have woodworking capabilities already?

I want do sealed. My overall budget is not infinite but I’m fine to spend 2/3k USD: of course less is better
Yes, I can do woodworking

Right now you are in the question phase of the project IMO. You shouldn't commit to do anything until you have a chance to review the options and decide what sounds like fun to you.

This is what I’m doing, or at least I think so

You'd only need a chamber for the woofers.

I see that a lot of commercial design have a separate tweeter (like the B&W): do I need to separate only the woofer then?

This would be a fun first build. https://www.madisoundspeakerstore.com/2.5-way-speaker-kits/uluwatu-sb-acoustics-tower-speaker-kit-pair/ great price good design and fun to cut your teeth on

Thanks for the link: interesting project

 

[lsiberian]

lsiberian,
thanks for the comments

What model are you using?

Got it

I want do sealed. My overall budget is not infinite but I’m fine to spend 2/3k USD: of course less is better
Yes, I can do woodworking

This is what I’m doing, or at least I think so

I see that a lot of commercial design have a separate tweeter (like the B&W): do I need to separate only the woofer then?

Thanks for the link: interesting project

I have a few different revisions the ones out now are much more reliable but be careful not to give them too much power or you can burn out an inductor. I also suggest you get the one already boxed. I wish I'd got the one with the box. I use the unbalanced kit, but you may want to go balanced if you plan to use a balanced amp.

The biggest cost of this project by far will be the amps unless you decide to use chipamps. Chip amps do work well, but they also can be noisy. I know mine give off a static that is constant for my speakers. I've looked at all sorts of different amps to upgrade from the chip ones and haven't yet found one that hits the price point I want or can afford. If you want to go chip amp you can get a board for 50US with 4 x 100 at parts express. You will need a power supply but those aren't too expensive.

Dome midranges typically offer the advantage of coming pre-chambered from the manufacturing. If you are building a 3-way I'm a big believer in having midranges that come chambered. It make life much easier construction wise.

However if you want my opinion on the best driver for each area.

Tweeter= RAAL. I love ribbons and they make the best. HiVi make good ones too if RAAL is to much for you.

Woofers= SB Acoustics. They make insanely good woofers that with a proper design don't even need subs.

Midrange = Morel Domes

I have not personally used the drivers above, but they are up for consideration in my next build.

 

[lsiberian]

One thing I wanted to bring up is that it's probably best to use a passive crossover for a tweeter to protect it. Since you have an active crossover you can actually do level matching there and then just use a simple crossover between the 2 drivers. If you want to shelve the tweeter that's certainly an option too. I don't actually use a cap with my tweeters, but they were 20 bucks.

 

[stonemarten]

lsiberian,

I also suggest you get the one already boxed..

Good! I've ordered the 2x8 with box

However if you want my opinion on the best driver for each area.

Thanks for the inputs: I'm considering different options. I will post later my final decision

One thing I wanted to bring up is that it's probably best to use a passive crossover for a tweeter to protect it.

Probably I will go passive for the tweeter and mid. I will post later what I'm going to do

Cheers