Please help me decide what to build

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Fast Eddie D

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Joined 2010
#1
I have a stash of wonderful wood that is suitable for building speakers or fine furniture. I have so many tools like saws (including table saw), jigs I only used once, a hardly used router and bits, etc. plus a motivated helper. It seems wrong not to build a speaker.

My goal is to build small speakers that are suitable for use with or without a subwoofer. My emphasis is on clear midrange, high output, and low distortion.

I'm looking at two drivers right now. Feel free to make another suggestion. I love this driver on paper, been itching to use it for years. https://www.parts-express.com/FaitalPRO-6FE100-6-Professional-Woofer-8-Ohm-294-1150?quantity=1 Also this driver https://www.parts-express.com/FaitalPRO-5FE100-5-Professional-Woofer-8-Ohm-294-1140?quantity=1

Using this calculator https://www.diyaudioandvideo.com/Calculator/SpeakerBoxEnclosure/ the first driver returns a vented box volume of 1.3 cubic feet. That's bigger than my 8" two-ways. I suspect if I build this it will be a wonderful speaker, studio monitor quality, but maybe too big.

This is where my limited experience takes me. Would it be worthwhile to "cheat" and configure a smaller box? The 5" midwoofers would probably fit the bill just fine (crossed @ 100 Hz) but the 6" drivers seem (on paper) to offer so much more, so fudging might be a good strategy - and this is where I need advice.

I'll look at other drivers etc (not too expensive) or advice on alternative strategies (passive radiator etc). Thank you!
 
#2
My plan is to cross the 6" @3 kHz or the 5" @4 kHz. My 8" is crossed over @ 2 kHz and it took a while to sort that; the drivers needed a notch filter and I had to fiddle with that to avoid "sucking out" the midrange. It was messy and I want to make the crossover as high as possible to make it less conspicuous. I intend to use an off the shelf crossover with a simple impedance correction circuit added on.

These drivers are (apparently) much better behaved in the midrange region than my 8" woofer. By all rights the 8" should be a 3 way but we always work within constraints. If I was going to go with a three way then it would have been 10-12" woofer. But bigger is harder to suspend from the ceiling, which is how I roll. Just like my new concept, the 8" speakers were intended as a design exercise as well as a practical speaker.
 
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#3
Fast Eddie D said:
This is where my limited experience takes me. Would it be worthwhile to "cheat" and configure a smaller box? The 5" midwoofers would probably fit the bill just fine (crossed @ 100 Hz) but the 6" drivers seem (on paper) to offer so much more, so fudging might be a good strategy - and this is where I need advice.
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It's basically all a series of trade-offs, and you will ultimately have to decide which ones are most important to you.

In general, professional/PA style drivers sacrifice some low-end extension for higher sensitivity. They accept larger enclosures to improve this as well.

If you want to design a small two-way with decent bass extension, a different style of driver is often useful. Consider the KEF LS50, and its relatively low sensitivity of 85 dB. The sensitivity isn't that low because they want it to be, it's because it had to be to get more bass out of a small driver in a smallish box. Your opinion of acceptable bass quantity and quality and overall sensitivity will influence what direction makes sense for you.
 
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#4
Thank you.

I'd be interested in considering different drivers, but the one you referenced is kind of silly price wise and concept wise. I'm building a two way.

Low efficiency isn't a problem. Low max spl is a big problem. My finished product will have to be able to perform in a low distortion, high spl system with subs crossed @100 Hz. I want them to be acceptable as stand alone speakers in a smaller system as well. Of course I'm not going to get high spl bass out of a small speaker.

It's clarity and output that attracts me to the pro drivers. The catch is that I want smaller enclosures than the simulation of the 6" indicates. I'm open to the size down with trade offs and this is where I need some guidance.
 
#6
I actually own a pair of Polk ES10s, and while they're pretty good as "jack of all trades" small speakers I'm actually disappointed in them as far as midrange clarity and their soundstage is a disappointment as well. My home made 8" two ways have way better clarity in the midrange (read not really that good) and way, way better soundstage than the ES10s. My intention is to best this mediocre (and quite frankly disappointing) performance by a very wide margin.
 
#7
The box could also be smaller if you go sealed. The bass would start dropping off a lot sooner, but at a slower rate, so despite sounding thinner there may be a bit more sub-bass. Also, since you plan on using subs, sealed mids will likely imtegrate a lot better and with less effort.
 
#8
Lojzek said:
It does not appear logical to use an off the shelf crossover and hope for a low distortion high quality loudspeaker. In that case a kit should score better.
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Sure.. But I'm going to "add on" an impedance correction circuit. I do understand why off the shelf crossovers almost never work the way they're intended. And I've done the fiddling before to make them work correctly.

I'm still open to a custom crossover, in stark violation of the KISS method. Anything is on the table except big bucks. I even wind some of my own inductors and have a whole kit of forms and enameled wire.
 
#9
abstract said:
The box could also be smaller if you go sealed. The bass would start dropping off a lot sooner, but at a slower rate, so despite sounding thinner there may be a bit more sub-bass. Also, since you plan on using subs, sealed mids will likely imtegrate a lot better and with less effort.
Click to expand...

Excellent points. It appears to me however that neither of these drivers is well suited to a sealed enclosure. As always I could be wrong. I've only played with them on paper.
 
#12
I thought the 6" had the demodulation ring as well. I'll have to look again.

I was leaning toward the 5" but I really like the 6". I like to mix my equipment up sometimes but since size is a paramount consideration and primary use will be with a subwoofer then the 5" is probably the way to go.

I'm disappointed with the Polk speakers. They're fine for computer speakers (and I really like the size) but I thought they might be a good candidate for use with subwoofers. I might be selling them short.
 
#14
With the 5FE120 I get a 0.45 cubic foot enclosure volume with an f3 of 43 Hz using a 1" x1.25" port. Perfectly reasonable, and crossing it @100 Hz with a sub hopefully will blend nicely. Will probably cross to tweeter @ 3.5 -4 kHz. We'll see if it's better than the Polks! I bet they are.

I haven't decided on tweeter but with such a high crossover there will be many choices I trust. I want to get the cabinets sorted so I can start building them.

I'm trying to follow the principle of having most of the midrange well away from the crossover points.
 
#15
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#17
I think the place to start is with where and how you will listen to them.

This will give you the size and shape, and the room's helps/hindrances.

When we build for a specific usage, we are way ahead of a general purpose design shoehorned into various usages.

You will be aided toward your distortion goals by knowing the output required at different notes, choosing your filters to maintain short travel for all diaphragms. Commercial designers share none of these advantages with us.
 
#19
Fast Eddie D said:
the one you referenced is kind of silly price wise and concept wise. I'm building a two way.
Click to expand...
I wasn't suggesting you buy it. I mentioned it because it's a well-known, highly regarded entity that demonstrates the trade-offs involved with small drivers and bass extension. You don't get everything in a nice small box with high sensitivity, high output, and great low frequency extension. You have to decide what you're willing to sacrifice and how. Some of your goals seem at odds with each other.
 
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