What matters most in speaker design?


So...What matters most in speaker design?

A. The Drivers
B. The Cabinet / Enclosure
C. Crossover / Internal Wiring
D. Cost / Quality of Raw Materials (Drivers, Cabinet, Crossovers, etc.)

Yes, I realize the "right" answer is "all of the above" or better yet "the design that optimizes the trade-offs of the given variables / parameters that achieves the goals set forth by the creator." However, indulge me...

Can a great sounding speaker get away with focus on only 2 of the 4 above choices? Can a high cost of raw materials trump a sound design that focuses on inexpensive (but great sounding) drivers, a well engineered cabinet, and a decent crossover?

I was thinking about speakers that use relativly cheap drivers, but are executed in a genius enclosure with a good (but not exotic) crossover - and they sound absolutely amazing. This made me wonder...

What matters most in speaker design?
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A, C, and D

No enclosure is best.
Price point, veneer, review, ad campaign, scuttlebutt, endorsements, gimmicky technological storyline, designer's pedigree, country of origin, power handling capability, and envy factor. Not everyone will agree on the order of importance among these essential elements.
The sound.
Weight.
The weight of all audio components relative to their function i.e only compare an amp to amp. The heaviest or most massive is always the better one.
Note I think the amount of wood in a wood or wood composite speaker can only be compared with another fundamentally wood speaker. Those granite thud rock slab speakers are cheating they get disqualified. Same with the lead lined cheaters thats not game.
So think about it which is better a thick highly braced enclosure or a thin non reinforced speaker enclosure. My JM Lab Focal Electra 938s are made with the same drivers (per JM) as the Utopias of that vintage. The Utopias weigh 3X as much.
Consider the drivers . Do you want that skinny excuse for a magnet always ferrite BTW compared to Alnicos magnets that weigh 10 pounds for a 1 inch tweeter and 30 or more pounds for a 10 -12inch woofer. Which is better. The bigger magnet. It makes for a more powerful motor in the driver it's true.
Finally crossover Skimpy three wind inductor a few small caps or....
So in sum, size or mass counts. Sorry fellow man, most woman are kind and reassuring but when they are alone...the size of your.... bank account really does matter.
No enclosure is best, I agree with Muralman1. That means planars, or certain special designs such as those buy MBL.

Soundlab, Sanders Sound, Quad EletroStats, Analysis Audio, Magnepan, Emminent Tech, Soundlab, GalloAcoustics, lots of cool choices.

Then the drivers, then the crossover network.
Resell value and brand recognition to be able to resell locally. ;)
Well the thing is, loudspeaker design is system design. Many an enthusiastic amateur has started out with "the best woofer, the best midrange, the best tweeter, the best crossover, and the best enclosure", and ended up with only an okay speaker. The professional designer takes everything into account at once, including in particular how it all works together.

I would say a good match between the drivers is necessary as a starting point, but in my opinion crossover design is the heart and soul of loudspeaker design. Cabinet design and construction matters, but it's not that big of a challenge in most cases.

Duke
dealer/manufacturer
If you are aiming to design one, go for it. Start from low cost speakers first around $20-40 each then enjoy and be proud of your hard work. Anyhow, a great completed set DIY from PartExpress can cost up to $900/pair while you could preferably buy a nice used set here and you can easily resell later.
Well, as you already know, a great set of DIY speakers can sound awful with a bad cross over design. A decent set of speakers can sound nice with the right x-over design. Guys from PartExpress.com can help you with more details and ideas. Sorry I can't give you a direct answer to your Q because I find that each one of them is crucial and somewhat related to each other.
Good luck.
Duke, a lot of the Klipsch Heritage speakers used to have the 3 dB point at 17.5 kHz. I assume this level helped smooth out the sound and mitigated some of the horn harshness. I noticed your speakers quote the same number under the category of system bandwidth. I think this top end is mostly a tube "limitation" and you mostly recommend tubes for your speakers don't you? Is that what you're getting at - a speaker for tubes? We're always quoted 20 to 20 as the range of human hearing. Are those last 2.5 kHz nothing but irritation? :) I always read with interest your posts about speakers and the obvious expertise. I'd like to hear a pair out here in the southeast.
C - crossovers.

Cabinetry, ala veneers and finish rule the day, with exotic drivers following closely behind. Cetainly a smart strategy, as this hobby is one where people listen with their eyes and their wallets.

However, in my own experimentation, by varying the cap/coil ratio, I could make my own loudspeakers become as forward and white sounding as a pair of Lumenwhites or as lush and full-bodied as Vandersteens, and of course, anything in between those two points.

Along those lines, the unfortunate thing is in this day and age, we are as far away from having competent people designing crossovers as we have ever been. Why? So many of the people designing loudspeakers today are deficient in mathematics; to the point where they run away from it.

For example, one loudspeaker manufacturer who I know, and has won awards at shows got his crossover design from a "friend" in the business. When I looked at it, the numbers were so far off, I jumped up to ask him how he came up with such off the wall(being kind) values, which is when he told me. Knowing the friend's talents lie in many areas of loudspeaker optimization, but not in designing (although he surely can upgrade/mod them to improve sonics) crossovers or mathematics, I approached the friend about the design, and he admitted he knows almost nothing about how to design a crossover. Where did he get these values? He kind of mimicked another speaker on the market he liked, but wasn't 100% sure if he was using exactly the same values. My money says that given the difference between commas and periods on either side of the Atlantic, a decimal point got lost in translation. What's worse is that even after a fundamental and major redesign of the speaker, the crossover has not changed one iota, "I have a crossover that works, and am afraid to mess with it." Really? I've told him the more appropriate values several times, but hey, the parts have already been bought and paid for.
I was thinking about speakers that use relativly cheap
drivers, but are executed in a genius enclosure with a good (but not exotic)
crossover - and they sound absolutely amazing.

Unless the manufacturer starts with high quality drivers then they won't ever be
accurate even though distortion and coloration can sound pleasant for some
provided the design is cool looking and has a nice finish. Distortion is
cumulative. Of course the drivers also need to be matched appropriately and the
woofer to the cabinet - so there are still many ways to mess things up even
when starting with good drivers.
I have a friend who designs speakers. I'd describe him as brillant - his dad is a department head at UVA. My friend has advanced degrees and has written at least one very thick book on signal processing.

I watched him build some speakers a few years ago. Very thick cabinet, the finest drivers, a lot of labor. I watched him work for months and months on the cabinet and later the crossover. He approached the cabinet design and x-over design from several angles eventually using some commercially available software for the x-over. He ended up with a perfectly flat frequency response and speakers that didn't sound too good.

Next he found someone with a lot of experience designing crossovers and worked with him for a few more months. They sounded better and eventually they got it to sound very good. He told me at one time he was thinking about adding some foam or rubber around the tweeter to take the edginess off the highs.

He took his speakers to a DIY show. I went as well. Basically he didn't win with the basic gist of it being the speakers weren't lively or forward enough. I didn't get it then but now I figure he'd built the kind of speakers you could actually sit down and listen to for a good, long while. They just didn't pass the "sip" test. The "sip" test is the first few minutes with the "boom and sparkle" jumping out at you.

Two important points I got out of this experience. First, all the parts he used were among the finest available and used in some very expensive speakers. But the drivers and crossover parts didn't cost much relatively speaking. Lesson 1: you pay as much or more for the design of the speakers as for the materials.
Lesson 2: A flat frequency response is no indicator of how good a speaker sounds.
None of the above.

While all those factors are important, they are secondary. The first consideration is the design concept. That must be thoroughly worked out and clearly defined before starting on the driver selection, crossover, or mounting/cabinet. How can a great result come out of a flawed approach? (Wireless200's story is a case in point.)
Hi Wireless,

Horn harshness really doesn't have anything to do with what's happening in the top 1/2 octave; it happens much lower down. It isn't necessarily caused by something that shows up in the frequency response curve either, but that's another topic.

I can't speak for Klipsch, but the tweeter I use has a mylar diaphragm and those tend to not go as high as titanium or other metallic diaphragms, but they often sound smoother. So indirectly the 17.5 kHz top end I claim is related to smoothness, but not because I think higher extension is undesirable; I just think that other factors matter more.

Duke
Lesson 2: A flat frequency response is no indicator of how good a speaker sounds.

True in that it will not sort out the wheat from the chaff but flat frequency response is a fundamental minimum requirement for accurate reproduction.
In some designs A & B is crucial.

C - doesn't apply since it isn't part of that particular design.
D - is subjective and varies based on application and design.

(the short answer to your "Q" if you can get away with 2 out of 4 points listed by you is - yes.)

I never understood why some insist on complexity (this also applies to audio reproduction/mastering in general) but we do what we can do best - I guess.

My admiration goes out to those who "did it" with out the "band-aid"!

Cheers
Mariusz
In my meager experience I would agree with Duke and others about the crossovers. That is truly where the art meets the engineering and can make or break a speaker system.

I have gone down the same path that Wireless' friend traveled. It is very easy for a DIY'er to do because we are limited in what resources we have available. So the tendency is to get the best looking specs whether they be simulations or RTA plots. When it comes to the crossover, the best resources to have are good and varied ears to help listen and give feedback. I can do Pspice simulations all day but none of them will tell me how it is going to sound. There is no way around this if one is striving for the best they can achieve. At this point all of the numbers have been used up. Now it is time to decide what sounds the most realistic by using your ears.
In my meager experience I would agree with Duke and others about the crossovers. That is truly where the art meets the engineering and can make or break a speaker system.

Great point - it is certainly the weakness of many designs - this is where active speakers have a huge advantage (with a degree of control & reduction in distorton that is simply impossible with passive designs).
Shadorne, I appreciate your posts and especially some of the links you've provided in the past. I know you're a big fan of Active speakers. Could you elaborate on the reason for that a bit more? From my perspective, how does moving the amplifier from its normal location to the speaker improve the sound?
The overall design matters most, and how well it is realized in practice, which entails all of the above.
Because single cone speakers do not generally use crossovers and crossovers being generally regarded here as the most important part of speakers design, does that mean that single cone speakers sound the best?hmmmmm.....lol..............
Its like asking "What is the most important organ in the body: brain, heart or lungs?" You need them all working together properly!
Wireless200,

The key with active speakers is moving the crossover to the line level side of the signal path rather than the high power level. This reduces distortion (capacitors have a sound and especially caps driven with high power signals can add distortion). This means that power amp/cable/speaker interface no longer matters, since there is line level cabling directly into very high (10K) impedance of the speakers. Furthermore the three separate amplifiers in a tri-amplified active three way speaker will only need to drive a limited bandwidth (say 20 to 400 Hz for the bass, for example). The limited bandwidth prevents IMD distortion from the huge 1 amp current needed by the bass woofer from affecting the tiny 1 milliamp current used by the tweeter. Another aspect is the ability to correct for phase - so the designer can maintain as near as possible an ideal transient/impulse response (good on drums/percussion/piano). Yet another aspect is the improved power performance due to less losses from heating up a passive crossover parts (roughly 3db louder for the same power). Low power requirements can also allow the design to be tailored - for example a tweeter is where the worst of the high order and most audible crossover and IMD distortion might be expected to show up - you could easily drive the low power requirements of the tweeter and most of the midrange in Class A while using Class B for the power hungry woofer. Finally, and related to the last few points, one can better protect the speaker from destruction due to being overdriven (often the tweeter blows when a conventional speaker is driven too hard but in an active speaker the tweeter still gets clean power even if the woofer is being overdriven).

Those probably aren't all the advantages but that is what I could think of at the moment. Of course, for those who like to tailor their sound like "mix and match" fashion accesories then the active speaker is limiting. However, if you want the speakers to produce music as closely as possible to how it sounded in a studio or in mastering then the appropriate active speaker will ensure you are quite close (simply because there are much less variables when a good 50% of the reproduction chain that you have matches what they used)
as i am new to hifi, can you give some examples of speakers/speaker companies that are "active" speakers?

what type of amp does one use with active speakers? or does one use two amps?

if there's a website that explains all this please let me know. didn't find it through google.

thanks, jeff
Jeff,

can you give some examples of speakers/speaker companies that are "active" speakers?

Examples of companies making active speakers are nearly too many to list here are a few (not exhaustive)
Meridian
ATC
PMC
B&O
KRK
Adam
K&H
NHT
Mackie
JBL
Tannoy
Yamaha
Westlake
Paradigm
Barefoot
Dynaudio

what type of amp does one use with active speakers? or does one use two amps?

A preamp only - or if you have a source with volume control then you can connect that directly (for example Benchmark DAC1)

if there's a website that explains all this please let me know. didn't find it through google.

Here is a lecture you can listen to Bob Stuart of Meridian
Jeff, ATC makes (truly excellent) active loudspeakers - I believe Shadorne owns a pair.

You'll find a lot more active loudspeakers in pro audio than this hobby. One reason being audiophiles really run the gamut in terms of power amplification, and they also are prone to a lot of buying/trying of them.
Ojgalli makes a very good point: "The first consideration is the design concept."

I agree. Doing a thing well isn't enough; it must be the right thing.

Duke
I have waited for a few responses before deciding to post one here. No doubt all points are equally important, especially A, B and C but the more complex part was in the crossover implementation. The speaker designer will most likely spend most of his time here.
It's been said that the Achilles Heal of loudspeakers is the passive crossover.

Consider the massive amounts of time and money spent fussing over the CDP, TT, DAC, preamp, amp, cables, interconnects, and more.

Why, after all that effort, is the beautiful, pristine, nearly perfect signal put through a passive crossover?
The design maters most.
Perhaps the look matters most.

A great paint job or veneer, tall and narrow with sloped baffle and loaded with several mass produced shiny metal drivers and impressive copper phase plugs to boot....all sure to impress. What people see is what they hear - for the most part. So the "Industrial Design" aspect is probably the most crucial - if it is ugly but sounds really good then it won't sell easily when lined up against the beautiful competition.
Shadorne, I suspect you are right assuming the target audience is the general population. No doubt that beauty is the ultimate marketing tool.
Up until the analog signal reaches the loudspeakers, it's a two-dimensional signal: Variations in intensity (voltage) over time. The loudspeaker has to deal with six dimensions: Variations in intensity (SPL) over time, across three dimensions of space (including reflections), and finally the signal processing of the ear/brain system.

Now the ear/brain system does not hear waveforms as such; it deconstructs the waveform into a series of excitations along the cochlea in a manner that is non-intuitive. So waveform preservation is relatively non-critical. In many cases audible benefits attributed to waveform preservation may well be due to other factors that matter more, such as minimizing diffraction or avoiding abrupt changes in the power response. I can explain why these things matter to the ear/brain system if anyone is interested.

Duke
The most important part of a speaker design? Listening to it after fabrication. Voicing it.
What is great sounding speaker? Sound depends on many factors and people have different preferences. Do you prefer speaker with underhung motors (less distortion and less dynamic) or overhung motors(more distortion and more dynamics) . Do you listen soft or loud. Do you listen to Jazz or Organ music? Do you crave for pinpoint imaging or heavy metal punch. Do you care how large sweet spot is. How does it perform in small or large room etc. How easy it is to drive.

Frequency response test is pretty much useless. Bad speakers with horrible phase errors might show with excellent flat frequency response.

I would agree with Shadorne on transducers. If pair of speaker costs for instance $1k then manufacturer sells it to stores for about $500. Components cannot cost more than 1/3 of it (to cover labor, expenses etc). Now we are left with $170. Both cabinets will cost $50 both and we're left with 120$ for let say 6 transducers and crossover components. That's why my speaker had originally $25 Vifa tweeter and Mylar + electrolytic caps in crossover. Good tweeter is 10x this and good cap is $100 (I just replaced $15 caps wit $100 caps of the same value and sound + imaging improved a lot).

There is no universal answer but you won't get very far with cheap transducers (especially tweeters). I don't design speakers but after concept design I would start with the best tweeter I can afford and worked down from it.
Uniform polar response with a slow monotonic decrease in total power above a few kilohertz preferably with less output towards nearby objects.

Getting there is a function of driver diameters, driver bandwidths, spacing, baffle shape/dimensions, and the cross-over.

There appears to be a point at which drivers are "good enough" in terms of distortion and stored energy.

Provided output levels are limited, you sit closer to accomodate the reduced directivity, and get farther away from the side walls my Linkwitz Plutos ($140 driver cost) are surprisingly close to my Orions ($1400).
"There appears to be a point at which drivers are "good enough" in terms of distortion and stored energy."

Drew - are you saying that Beryllium tweeters in new Revel Saloon 2 or diamond tweeters in B&W are mistake (unnecessary expense)?
I originally thought flat frequency response was a primary goal. And it is, IF damage done to achieve this is minimal.

BUT having listened to single driver speakers with no x-over and then adding different tone controls, [DEQ24/96, Parasound Z-pre, 3-band tone control] to flatten the response, I can say any manipulation of the signal makes the sound worse in more important ways. Assuming the driver F-R is fairly flat to begin with. For example, NOT metal with some crazy break up mode or peaky high efficiency Fostex/Lowther.

I find I can mentally compensate for uneven F-R BETTER than the distortion and phase shifts that come with ANY tone control that I have found. A classic case in point is the Eggelston Andra that switched from an uneven mid-driver with no x-over to a flat F-R but with x-over. Surprise was many listeners preferred the older design.

Also, I am adjusting the signal the "right" way, at line level, not AFTER the power amp where passive x-over parts will color the sound even more. And for those who HATE tone controls, you should be aware that designers build tone controls INTO passive x-overs to flatten bass or add the famous 5dB boost at 100hz.

Expressed here better than I can:
Read Johnnyb53 re Flat F-R

So to answer the OP's question in terms of the driver itself, I will respond by repeating what Seas says:

1) Low non-linear and modulation distortion.
2) Excellent transient response.
3) Good coil excursion.
4) Pistonic response.
5) Large windows in the basket to reduce sound reflections, air flow noise, and cavity resonances.
>11-16-11: Cdc
>I originally thought flat frequency response was a primary goal. And it is, IF damage done to achieve this is minimal.

>BUT having listened to single driver speakers with no x-over and then adding different tone controls, [DEQ24/96, Parasound Z-pre, 3-band tone control] to flatten the response,

1) Unless you were doing some form of reflection free measurement (anechoic chamber, speakers buried in the ground and measured in half space, or a gated measurement of some sort most likely using Maximum Length Sequences and software like ARTA) you were adjusting for flat power response which you don't want instead of flat on-axis response with smooth off-axis curves which you do.

2) Unless you were using a calibrated measurement microphone you weren't adjusting for flat response there either.

3) Toole and Olive have found that listeners prefer flat on-axis response with smooth off-axis curves regardless of nationality and preferred musical genres. Olive turned that research into a speaker ranking formula which correlates well with subjective listening tests.
It's been reported that John Dunlavy thought step response was what mattered most in speaker design.
>11-16-11: Drew_eckhardt
>1) Unless you were doing some form of reflection free measurement (anechoic chamber, speakers buried in the ground and measured in half space, or a gated measurement of some sort most likely using Maximum Length Sequences and software like ARTA) you were adjusting for flat power response which you don't want instead of flat on-axis response with smooth off-axis curves which you do.

Even then it's not enough. It's possible to have an on-axis dip with a power-response peak where it's better to cut power response at the expense of degraded on-axis response.
Drew, That is interesting. I thought flat power response was the goal:
Earle Geddes - waveguide loudspeakers

I was using a calibrated mic and measuring the F-R 3 feet from the driver. This is very different from what I measured where I sit. Anechoic is nice for theoretical design but in-room (like JA's Stereophile measurements) can be a whole other animal. So what is correct in the reality of the listening room?

You can analyze it to death and if you want to be picky enough - angels dance on the head of a pin -, never come to the "ultimate" solution. This is a legitimate endeavor but I just want something useful for my 'umble setup.

I am kicking around Seas W15LY001

As you can see, at 30 degrees off-axis, it's a pretty flat response. Just add a supertweeter + L-pad above 8kHz.
11-21-11: Cdc
>Drew, That is interesting. I thought flat power response was the goal: Earle Geddes - waveguide loudspeakers

Earl's speakers don't have flat power response. They're omnidirectional at low frequencies, narrow gradually as the mid-bass becomes acoustically large with declining power response, have fairly constant directivity and power response for around a decade, and then narrow with decreasing power response. With flat power response they'd sound unnaturally bright. He has nomographs on his web-site plus a Windows program which can display them for various speaker data.

If you haven't yet you need to read _Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms_ by Floyd Toole and peruse Sean Olive's blog (they're both members of the Harman International research group with a financial interest in figuring out what people like in speakers) which get you to flat on the listening axis (Earl does that) with smooth off-axis curves decreasing monotonically with frequency (Earl does that too).

Most speakers lack smooth monotonic off-axis response and therefore don't sound natural. Conventional cone and dome two-ways have directivity mismatches between mid-woofer and tweeter. Panel speakers are acoustically large at high frequencies which produces a multi-lobed mess. Large full-range drivers are ill-mannered.

The ones which get that right sound surprisingly similar within their passbands and output level limits in spite of radically different designs. Examples include wave guide tweeters crossed to large mid-woofers where directivity matches, some coaxials, the Plutos where the drivers are acoustically small with perhaps 1/4 wave length between acoustic centers at the cross-over point, the RAAL Requisite Eternities with uniform horizontal off-axis response and mid-range array that should have vertical polar response which matches well to the ribbon tweeters, and small full-range drivers.

>I was using a calibrated mic and measuring the F-R 3 feet from the driver.

That doesn't correlate well with perception without gated measurements (like MLS signals via ARTA or MLSSA) because about half the power is coming from the reverberant field without consideration for the time domain although our brains seem to perceive timbre based on the spectra from the original sound and what they identify as reflections.

>Anechoic is nice for theoretical design but in-room (like JA's Stereophile measurements) can be a whole other animal. So what is correct in the reality of the listening room?

Flat on-axis with smooth monotonically decreasing off-axis curves where there's some latitude to balance too much output in one area with less elsewhere. That makes reflections which sound like the source probable regardless of what angle they're coming off the speaker and what they bounce off of.

I'd speculate it comes from evolution - we needed to identify predator + prey animals and their locations in spite of reflections off objects and the ground plane where outdoor environments are more absorbtive and diffusive at higher frequencies.

Siegfried Linkwitz put a shallow (about 2dB/decade) shelving low-pass filter on current Orion incarnations which sounds less bright and more natural, with an offered explanation being that the slope closely compliments HRTF differences between a real source straight ahead and sounds arriving at angles from a pair of speakers although polar response broadens going from the mid-range to tweeters and compensation for that is a plausible explanation consistent with John Krevosky's experiments (he built Orions with the original transfer function and perceptually matched better behaved speakers with acoustically small dipole tweeters to them with a high frequency boost).

At Burning Amp 2010 he said that his Plutos were no longer flat on-axis either although I didn't inquire for details or measure mine.

>I am kicking around Seas W15LY001 As you can see, at 30 degrees off-axis, it's a pretty flat response. Just add a supertweeter + L-pad above 8kHz.

Behavior at 30 degrees isn't enough. For example, in one of my listening rooms I looked at the first reflection angles as a thought exercise and noted that the side-wall reflection came from the sound 37 degrees off-axis which became 67 degrees off-axis with toe-in.
Everythig you said.
Nrenter
Do you want to build some speakers? Just curious how you decided to open this can of worms.
To design, you need a very good understanding of how the individual drivers will react in what type of enclosure, you'll need to understand lobing and how crossover frequency curves that behavior, you'll need to understand cabinet difraction and how crossover curves that behavior, you'll need to understand impedence swings and how crossover curves that behavior, you'll need to know time alignment and how crossover/cabinet design helps alignment, you'll need a good understanding of what different crossover slopes sound like and mixing sensitivity of drivers and which drivers you can pad and which drivers you cannot, driver resonances, controlling phase, on axis response vs off axis etc, etc etc and I can go on. Driver choice... not the cost is very important, but the real deal is understanding how to use them. Crossover design is number one, driver choice number 2, cabinet is number 3. It is possible to find drivers with very smooth rolloff that require minimum crossover that can make GREAT speakers, but hand someone some speakers with difficult curves and thats were you seperate the men from the boys.... unless your a woman, then the girls from the women.
Drew, I'd like to hear the Plutos and Orions.

Behavior at 30 degrees isn't enough.

What does this mean? Of course HF need a super tweeter with a hi-pass filter

You can see Zaph's distortion/ FR / measurements Here

What do you think about Seas W12CY003
or
Seas ER15RLY