Sunday, May 29, 2016

Somatic Response to Music

One thing I've wondered about on and off has been whether we really perceive all of what speakers make just through our ears. How much of the listening experience occurs in the body?

Now it seems an article on Salon starts to discuss this very issue.

http://www.salon.com/2016/05/29/an_orgasm_for_the_skin_partner/

Enjoy.

Saturday, May 28, 2016

Custom Speaker Making

I've put together this page to help those who know that speaker prices in the stores can be ridiculous and no guarantee of quality. 

If you don't want to do anything but unpack speakers, consider buying complete speaker systems from reputable custom speaker builders such as:

Fully built systems from around $2,500 to $5,000 are typical and will beat most speakers at $20,000 in a store.

If you want to learn more about building speakers yourself, please start by visiting these sites:

Of course, I'm quite proud of the free DIY kits I have published on this blog, you can start by looking at the LM-1 posted here as well as my review of other kits here.

Stereophile Reviews - The Data Doesn't Lie

Update September, 2016:  The story has now grown to include the very short but biased review for the Crystal Cable Arabesque Minissimo which you can read here.

 

 Introduction

For a long time I've had trouble matching up Stereophile reviews with my experience of the same speakers. I think I've found the reason why. They aren't reviewing speakers at all. They are reviewing hearing aids pretending to be speakers. This is why they are so expensive.  What I mean is that the speakers Stereophile praises would only sound good to some one with hearing loss between 7kHz and 15 kHz, which I lack.  It's clear that completely different manufacturers have taken advantage of this  "trick."

I'm calling this trick the "Stereophile Curve" and the more I go back in time to look at megabucks speakers rated highly, the more apparent the truth of this curve becomes. Of course, the alternate, benign explanation is that the reviewers have all bought the B&W studio heritage hype, and they have become accustomed to thinking of the B&W 800 series speakers as a neutral reference, which, objectively, they can't be.


The Stereophile Curve

 A recent review in Stereophile for the B&W 802 D3 speakers prompted a reader (AV OCD I think) to post pictures showing just how similar the frequency response of the D2 was to the D3, despite the glowing reviews from Kalman Rubinson for the D3's superiority. The reader was right, the frequency response aligned nearly identically. Mind you, that's no proof of anything except that it's hard to match up the comments with the data. But as I looked more closely at AV-OCD's charts I realized that I had seen nearly identical measured response curve elsewhere, in the review for the Golden Ear Triton 5!

Several of the most highly touted speakers Stereophile that reviews not only have pretty ragged and, in my humble opinion, substandard frequency response, they are also ideal speakers for the hearing impaired. That's the nice way of saying, they are deliberately tweaked in the same way. Shenanigans say I!

Let's compare the B&W 802D, 802 D3 and the Golden Ear Triton 5:



See the dip around 6 kHz and the bump around 11 kHz? To me, having heard 2 of the three speakers in the chart above, this looks like the Marquis DeSade's setup. It also explains what the reviewers at Stereophile are raving about. There is no reason for this by the way except deliberate mis-tuning of the crossover from neutral or ideal. It also tells me this:

If you are using B&W 802 series speakers as references for record mastering or post-production, please stop it, stop it now! They aren't going to match most home speakers or any well-calibrated cinema.


Listen, if you like the sound of any of these speakers, and can afford them, you should go buy them, especially if you have complementary hearing loss but what you won't be able to do is to convince me that I'll like any pair of speakers Stereophile recommends, I just don't have the hearing loss in the same place that they seem to.

The Sony SS AR1 Review

The Stereophile review of this speaker was the most lukewarm review I've seen them publish for a $20,000 speaker.  What happened? The frequency response is not what is in vogue. Take a look at the Sony vs. the B&W 802 D3 measurements:


The B&W 803 D3 measurements are in red. I've circled all the important parts of the "Stereophile Curve" in red. As you can see, the Sony AR1 misses all the key parts. From the left, the 2.4kHz dip i s a known imaging/depth enhancment. It makes speakers appear to have better imaging than the recording actually has. Several Wilson's are tuned with this as are the Focal Sopra 2s. After that it seems to be a trait of the B&W's, regardless of their midrange. By the way, that Golden Ear was able to match B&W's curve so well is a testament to the versatility of AMT diaphrams. Being mostly resistive, creating an EQ curve to match other speakers is much easier.

Mind you, I'm not really happy with the Sony AR1 response anyway, it's not neutral but more of a party tuned speaker.  My point is that Sony did not know about the current fads in the high-end, and if they had they would have had a much warmer reception.

Exceptions to the Curve

There are exception to the Stereophile Curve, such as the Wilson Audio speakers, which just have terrible and inconsistent high frequency response. The Wilson XLF did seem to follow this curve though. YG Acoustics is one of the rare exceptions that proves the rule. Exceptionally good frequency response. Never heard them.

Explanations? Not sure, but they seem to correlate well with the number of full page ads. Take a look through any show report in the last 5 years at Stereophile. I'll let you punch me in the arm for any show report that doesn't include a painfully boring picture of both a Wilson AND YG Acoustics demo room. 

Alternatives to the High End Speaker Hype

The speakers that I like to listen to neutral and gimmick free, at least until my hearing gives out. If you feel the same way, please help stop the madness by buying from custom makers or by building your own speakers.

Please feel free to take a look at any of the good kits mentioned in this blog or my blog page which focuses on Custom Speaker Making, here.

Hearing Loss

By the way, if you do have hearing loss, building speakers, or adding equalization to make speakers sound better for you is quite easily and cheaply done! Dan D'Agostino, founder of Krell and now  his own company has had hearing aids specially tuned for him for years. He seems to have coped quite nicely! There's no reason why you can't remain a music and audiophile in the 21st century even with moderate hearing loss. miniDSP is your friend!

This blog post is not out to berate some one for a health condition. It may however berate an entire industry for selling hearing aids masquerading as loudspeakers for tens of thousands of dollars or more. Hearing aids, whether the kind you wear in your ear, or when disguised as loudspeakers should be affordable for all, and reviewers should know better. 

Friday, May 27, 2016

LM-1 Bookshelf Complete Part List

The part list for the LM-1 Bbookshelf Version is here. The only things missing is wiring and crimp connectors as well as adhesives and circuit board surfaces.

In the US Parts Express usually has all of these parts, especially the hardware but Madisound often has better driver prices. For the crossover parts I buy a lot of Mundorf MKP, Mills and Clarity ESA caps so I tend to buy most of those from Parts Connexion except for the Jantzen coils which always come from Parts Express.

For a detailed discussion about the crossover components and drivers please see the blog entry titled LM-1 Bookshelf Crossover.


NamePart TypeValueSecondary ValuePer SpeakerPer Pair
C1,C3Capacitor8.2
24
C2Capacitor18
12
C4Capacitor1
12






L1Inductor0.4418 ga.12
L2Inductor1.215 ga.12






R1Resistor3.912 W12
R2Resistor1.212 W12
R3Resistor1012 W12






S1TweeterVifaXT25BG60-041
S2WooferPeerless8309911







CabinetDaytonTW-0.25 or TWC-0.25(Comes in pairs)1







Bass Port1.5"4" long12

Banana Terminals

(Comes in pairs)1







Acousta-Stuff


1 lb.

Sonic Barrier3/4"3-layer
1 Sheet



If you decide to make your own cabinet, you MUST maintain the baffle dimensions of 190.5mm x 304.8mm or 7.5" x 12" AND you must ensure the internal volume is at least 0.28 cubic feet.  The internal volume can be up to around 0.35 cubic feet, so don't sweat that so much.

Wednesday, May 25, 2016

Sony Speaker Costs

In the post A Cynical Discussion of Speaker Pricing I make the point that commercial high-end speaker pairs cost from 20 to 30 times the driver cost of a single speaker.  This is just a little math to make it easier, but it's equivalent to 10 to 15 times the cost of all the drivers in a  pair.

In this post I present a slightly more detailed example of this for those of you who are still incredulous. I'll use the Sony AR1. Sony is by no means unique in this field by the way, it's just that the Sony AR1 lends itself particularly well to public scrutiny. 
 
A discussion on another topic over at the DIYAudio forums led me to post an example of how speaker prices are so high. Here is a part of that discussion, and my thanks to the contributors including planet10 (Dave):

The Sony SS AR1 MSRP to Driver Cost

Here's a good example, the Sony SS-AR1.

All Scanspeak, off-the-shelf drivers, and they don't even bother to use the top of the line Beryllium tweeter either. Retail is around $27,000.

By the way, I am a huge Scanspeak fan, I think Sony did well to choose them. That's not the point I want to make here though! The real point is that at Madisound a hobbyist would spend around $2,110 in speaker drivers per PAIR! So, counting the speaker drivers, the markup from hobbyist to commercial speaker is around 13x. Add in that Sony probably gets a 35% discount and Dave is then exactly right, it's 20:1.

Of course, this doesn't count labor, lumber or crossover components, usually the crossover is not shown when they spend as little as possible on them.

Tuesday, May 24, 2016

LM-1 Bookshelf Crossover

Schematic

The schematic along with the driver simulation data is available in the form of an XSim file you can find in this discussion. Feel free to explore this design and it's choices. 

At this point in the exploration, I've completed the final draft of the speaker schematic. Having a little more time and energy I was able to get better measurements and re-think the crossover entirely. The final schematic is very simple and uses only nine crossover components.

In the end I used nearly symmetrical second order filters for both sections. The tweeter's -6 dB filter point is right at 2kHz but the woofer is rolled off a little earlier, around 1.5kHz. 

Let's take a look at the "transfer function" chart, or as XSim calls it, the "electrical response" chart. This plots the difference between the amplifier and each driver and shows us what our filter choices are doing electrically. Remember that these effects are additive to the drivers, they are never independent of the driver response or impedance.

As  you might expect, it's pretty simple. The woofer has no change up until around 700 Hz where the low pass filter begins. The super straight line is partly due to the zobel. Notice however that the tweeter level is significantly lower, about 6 dB below. That's because it's much more efficient, and we needed the R1 to bring it down.  The ripple you see in the tweeter slope is due to the tweeter's own impedance interacting with the high pass filter.

Tweeter Level

In the chart below the blue trace represents using the recommended 4.2 Ohm resistor. The red trace shows the effects of using an 0.5 Ohm resistor. The point of showing both of these lines is that you may substitute any resistor between 0.5 Ohms up to 5 Ohms while still maintaining excellent phase matching, so make yourself happy! 


Zobel Network

C3/C4 and R3 are a Zobel network which of course not only smooths out the frequency response of the woofer but in this case also allows for near perfect phase matching with the tweeter.  In a pinch, any combined value of C3 and C4 between around 8.4 and 9.4 will work, but 9.2uF is the optimal value.

Acoustic Distance

The acoustic center of the woofer and tweeter are offset by only 1.1". The small 5 1/4" driver is shallower than the 6 1/2" equivalent plus we are surface mounting it, pushing the woofer towards the listener. Thanks to this combination we have really struck crossover gold in terms of phase matching. A quarter inch the other way and this simple design would have turned out much more difficult.

Part Selection

For your convenience, a Complete Parts List is in another page, but here we discuss choices for the drivers and crossover components here.

Drivers

As with Kirk's design, I'll be using Vifa tweeters and Peerless woofers:
  • Vifa XT25BG60-04 1" Dual Ring Radiator Tweeter, $35. Please do not attempt to use the smaller, and only slightly less expensive Vifa XT25TG30-04, it lacks the low-end extension. This driver is also sold for more money under the Scanspeak brand. If you think you spy the tweeter in some megabucks speakers, you aren't wrong. It's the same unit, or often the next model down from this one.
  • Peerless 830991 5-1/4" GFC Cone HDS Woofer $35-$45
The $45 fiberglass driver could be inexactly substituted by the the Peerless 830656 paper cone woofer which cost around $20 each. In combination with the cheapest possible crossover capacitors you will get to around a $400 price point. Of course, the biggest savings is to build the cabinets yourself.

Crossover Components

I present a few different crossover grades below. Regardless of the choice of crossover caps and resistors I always recommend Jantzen air coil as the starting point. L1 should be 18 gauge, L2 should be 15 gauge. Do not use a bigger gauge coil on L2! The temptation is there, but the DCR is part of the design. If you must "mod" the coils, use a small-guage foil coil for L2 such as the Goertz 16 guage 1.2 mH coil available at Madisound or any other coil with a DCR between 0.330 and 0.4 Ohms.

Cheapest Possible

To stick with an absolute bargain build, use with Bennic caps and Dayton audio grade non-inductive resistors. 10W is close enough if they don't have 12W. You could save a few more bucks ($10 total) by using bi-polar electrolytic capacitors in the woofer, but please don't.

Frugal Freddie's Compromises

If you want to spend just a little more, I suggest Mundorf MKP ($8) for the 8.2uF cap in the tweeter section. Use Mills resistors. Audyn and Jantzen are also highly thought of.

Balanced Betty

Betty buys parts that are matched by the price and quality of the drivers. She would suggest Clarity ESA cap in the tweeter section of if you want to stay with all Mundorfs, the Mundorf EVO Aluminum in Oil. Either should be under $20.

Stick with Mills resistors everywhere, and Mundorf MKP caps in the woofer section.To keep costs down she might choose Axon caps in the woofer though.

To the left you can see my own build. I ended up using Clarity for the tweeter, along with mostly Axon caps in the woofer section. To make a boring story short, I happened to have 7.5uF Axon's lying around, so I got 1.8uF Mundorfs to make up the Zobel. All resistors are Mills.

The savvy builder will note that the coils are aligned in the same Z axis. Not to worry, the boards themselves will be mounted at 90 degree angles! One on the bottom of the speaker and the other on the side. 

The "OMG Are you nuts?" Build

Use Jupiter copper film caps for the tweeter. Capacitor cost? About $800 per pair of speakers. Hate your kid? Does he/she have an overripe  college fund? Do it!  OK, I'm kidding, it's completely out of balance. Save this kind of money for your $300 or more tweeters.


Please feel free to experiment with parts you like, can afford, and have available. These are just my personal recommendations. If you find caps you think work really well leave me a comment.

The Scientist Build

This speaker lends itself very well to learning about the sound of capacitors. The reason is the very high quality tweeter and that it uses a single capacitor. If you like the idea of experimenting with capacitors yourself, I'd suggest you wire the crossover so that the tweeter cap is external. Add a second set of banana jacks on the rear, spaced about 2-3" apart and connect the tweeter capacitor there. Now you have a very convenient experimentation lab which would allow you to swap capacitors or add small bypass caps instantly.

Driver Phase Matching

"Phase matching" refers to how well two drivers play together across the band in which they both  contribut. I usually use the -20dB level as my cut-off (more or less). You can see in the chart below that this is about 700 Hz to 3kHz. That's actually a pretty broad range brought about by the low crossover slopes. Still, notice that wihin this range the dotted red and green phase lines are so close together.

We can also see that the phase alignment where they cross 180 degrees is perfect. The longer the phase angles match the more the drivers will blend in with each other and disappear. Here's another view of that effect. Let's compare the normal response with an inverted driver (either one). In theory this is the absolute worst possible alignment:


Not only do we have a 20 dB dip at the crossover frequency, but look at how symmetrical and broad it is. Again, that the inverted driver produces this text-book null indicates the LM-1 have excellent phase matching before, during and after the crossover region. This will allow the drivers to blend in, minimize lobing and comb-filtering as the listeners location changes.

LM-1 Bookshelf Measurements

My Little Soapbox

The industry, commercial and DIY, has gone to trying to use purely theoretical environments to judge their driver and speaker performance with the idea that building an environmentally neutral speaker will make it suitable anywhere. Part of this is not just what's best, but also what's most convenient, and more marketable. And honestly you can be very successful this way.

Still, like Alison, I do not believe this to always be the best way to approach speaker design. My evidence is how many "bookshelf" speakers have become stand-mounts.  The LM-1 was tailor made for music lovers with modest listening rooms and small budgets, so these measurements and methods are completely suitable and accurate for their intended purpose.

Frequency Response

Allow me to present the simulated vs. actual response. The blue line represents the simulated response, the green line is the raw far-field, 1/6th octave response of the entire speaker placed so the front baffle just overhangs a 16" wide bookshelf.


The level is offset for clarity. When overlaid, the two graphs are in almost complete agreement.The simulation used close-microphone techniques to eliminate the reflections which plague us during crossover design. The green line however was taken at 3'.

What was not expected in this design is the dip between the port and driver around 74 Hz. None of the box simulations show this. The port's actual tuning frequency is "too low." Others may call this a happy accident though, as this brings the bookshelf/desktop response to.... (wait for it!) 40 Hz in exchange for the dip at 70 Hz.

You may also notice that the curve slopes downward, which is a good thing and shows the LM-1 closely matches the famous Bruell and Kjaer target curves.

Efficiency

As a result of carefully matching the speakers to their environment, we've come up with some pretty sensitive (for small) speakers, around 88 dB /2.83V at 1 meter. That's quite nice. Not in the range of horns, but small speakers like this usually really can't get such a good result. Note that part of this is that my drivers measured more sensitive than spec in the bookshelf, around 89 dB, and that the crossover excludes most baffle-step compensation.

Had we designed this blindly adding baffle-step compensation we would have ended up with a pair of speakers that were boomy, much less sensitive (83 dB or so) when placed in a bookshelf. Conversely, if we had tried to use this woofer in a stand mount we would never have this much bass. We would probably loose at least an octave.

Impedance

This is a very easy to drive speaker. The impedance stays well away from 4 Ohms at all frequencies and in fact stays closer to 6 Ohms for most of the plot. I would easily call this an 8 Ohm speaker based on this and how commercial speakers are rated. Here we have the simulated impedance charts for both versions of the speaker. The green line is of course the ported version:


These are just simulations, but the actual Z is very very close. I'll try to post them before 2017, but no promises.


Notice also the impedance below 200 Hz  stays above 8 Ohms! Oh my Dark Goddess of Espresso Coffee Beans, this is a dream speaker for most amplifiers. You could practically drive them from an iPod. Any receiver or integrated amp will be absolutely over-joyed to play these speakers.

Raw Files

The XSim files are available, letting you play with the crossover design yourself. Please join us at the DIY forums here.

Step Response

I don't have any tools right now to allow me to measure the step response, but I can simulate it using XSim. It's perfect for a 2-way that is not time aligned. The tweeter starts in a positive direction with just a touch of pre-ringing, and the bottom of it's response blends seamlessly into the rise of the wide-bandwidth woofer whose output is almost perfectly triangular. Outstanding!!




Conclusion

We have gotten really fortunate. In addition to the frequency response, it's very difficult to find a speaker with such flat response, low cut-off frequency (55 Hz-ish), high impedance, high sensitivity and fantastic phase matching across the crossover region. Usually we have to give one or more of these items up. Except for the limited output, these may be the best inexpensive full-range (kind of), high-end loudspeakers you can make yourself.

Thursday, May 19, 2016

LM-1 Measurement Tools

The designs I present as part of the LM series don't need any of the measurement tools here.  You can buy the parts, cut the holes and solder the crossovers without them.  What I'll be doing with these tools is showing the entire design process so that those who are interested can go on and create their own designs. Much like Dr. Leach did for me in enabling me to think and understand processes that were completely opaque to me before I sat in his class, I hope I can do for a few of you.

In the 21st century the DIY builder has access to buying or downloading tools that only graduate students or professionals in the audio or car industry had in the 1980's. We'll take full advantage of modern tools and while I'll point out some free tools, I'm pretty set in my ways with the inexpensive commercial tools I use. However the steps and processes won't change much regardless of what measurement tools you use.  The primary measurement and analysis tools we'll use are:


You can save $50 by buying OmniMic and DATS together via the Parts Express website. Free alternatives to OmniMic include Room EQ Wizard and others but I'm afraid I don't know much about how to use them. Of course, even if the software is free you'll need a decent microphone. At about $20 the Dayton iMM-6 is pretty much the cheapest there is.

XSim is just an amazingly accurate simulator, allowing you to try alternatives in seconds what before would have taken real hands on experimentation. We'll take the outputs from OmniMic and DATS to analyze our design from start to finish. When we're satisfied then we'll order crossover parts.

Wednesday, May 18, 2016

A Cynical Introduction to Speaker Pricing

Building a well designed kit with good parts is a large cost saving measure. You can have speakers better than commercial speakers costing many times more.  This is particularly true at the top range of the speaker markets.

To understand why a kit will often sound much better, and cost so much less I'd like to use the modest $500 DIY price for the LM-1 kit. In the introduction I mentioned that if you bought them in a store you'd have to pay around $1,500 for similar parts quality. Let's go over the math a little bit. Of course, Ginsu sells knives the same way. "This $3,000 40 piece knife set can be yours for only $19.95" so you have no reason to trust me except that the design for the LM-1 is free. I make no money whether you build a pair of LM-1's or not. So at the very least I lack the financial interests reviewers, manufacturers and salespeople have when comparing them.

So-called High End speakers manufacturers end price speakers based on the cost of the drivers. If you know the speaker's Manufacturer's Suggested Retail Price (MSRP) you can pretty much figure out the driver cost. Of course, in reality it's a closely guarded secret, and brands will add a dot with a Sharpie here and there to claim exclusivity of drivers.

The ratio between MSRP / pair to driver cost for one speaker is between 20:1 and 30:1 in the audiophile market. It may be significantly higher if the manufacturer makes their own drivers like Focal, B&W or Dynaudio do or if it's a feature or lifestyle speaker like Bose. With $5 parts and $1,500 price tags their 5.1 speakers are a manufacturer's dream.

So, let's take the LM-1. Total driver cost is around $65 per speaker. 65 * 20 = $1,300. At 30:1 the price would be $1950. A budget floor standing speaker by a designer the current popular press is raving about, retails for $1,999 a pair. Within our estimation range. Maybe we should compare a pair of the LM-1C's instead, but I don't have as good measurements for those. Let's stick to the LM-1.

To be fair, frequency response of speakers is only the first thing to look at. There are many other factors, especially your ears. However, for a bit let's take flatness as a measure of quality and compare the LM-1 to the Stereophile measurements:



The commercial $1,999 speaker is in Red, the LM-1 in blue.  Mind you the LM-1 data is incomplete in the bass. The effects of the port have not been added in so the true -3 dB point is actually going to be very similar, within 10 Hz or so. The commercial speaker is also about 3dB more efficient than the LM-1. It will need half the power to reach the same volume. Not a bad thing, but also not an overwhelming plus.

Forget the bass though, look at the response above 1 kHz. See that 6 dB bump at around 10-15kHz? Ouch! That has to hurt. By comparison the LM-1 kit produces a very smooth and extended response that slopes downwards at a perfect angle to produce a very neutral and musical in-room response. Of course, this is my personal preferences talking.  My point is, if the speaker reviewed by Stereophile merits a $2,000 price then the LM-1 deserves an even higher price tag. I have heard the speakers Stereophile reviewed by the way, they sound exactly as you would expect that red curve to sound, which in a word was "terrible." I thought the dealer didn't like how I dressed and was deliberately trying to torture me. As bad as the uptilted treble was, the AMT seemed to also suffer from severe compression artifacts, an indicator of a very cheaply made AMT. Good AMT's are amazing.

Interestingly Troels Gravesen makes more good points about commercial speakers and just how bad they really can be despite good reviews here.


Unseen Components

Manufacturers are really under no obligation to factor in high quality parts, so they often don't. They find the cheapest provider of film caps and have them wrap custom plastic around them to appear unique. A couple of rare exception to this is Magico, and Lawrence Audio

Sometimes it's the cabinetry itself that's hidden.  It's unbelievable to me that you can paint press board tubes and charge more than $20 for them, which brings us to the next topic in this discussion.


The Value Curve

Over at Part Time Audiophile there's an absolutely great slide with Focal Vice President Gerard Cretchien explaining why the Focal Sopra is his idea of the best speaker in the world. What's most interesting is that from the point of view of a manufacturer, sound quality and performance is only one of many different measurement aspects that need to be optimized. Gerard is doing exactly what he should be doing, creating products with as much perceived value as possible. Good for Focal for having such a dedicated ally who is able to communicate to the dealers so well. As he explains, items such as modernity, technology (perceived advancement), brand recognition, etc. all combine to produce the final "perceived value" equation.  These speakers aren't just music reproduction devices, they are lifestyle emblems, and he knows it.

At the same time that this slide is text-book product development 101, for the inexperienced DIY builder it explains why it is possible for us sawdust covered, wannabe engineers (OK, some of you are real engineers) to build amazing sounding speakers for pennies on the dollar. Focal is charging money for "brand" and "modernity." Imagine if you could get the same quality parts and not have to pay for either. To look at Gerard's chart, each dot is worth about $2,000, so every feature you go "meh" to is another $2,000 less on those $14,000 Sopra's. Do the rest of the math yourself.

Shenanigans

  • The most highly rated speakers at Stereophile follow a particular "Stereophile Curve." Great for those with hearing loss, despite their terrible sound for everyone else. See more here.
  • One famous British company actually makes two identical speaker models but one costs $300/pair more. The only mechanical difference is that a single $1 tweeter capacitor is replaced with an $8 Mundorf caps to make their higher end speakers sound better. In this case, $16 in parts becomes a $300 up sell. 
  • Another equally famous American company buys tweeters for $18 each, puts a custom back on them then puts them into speakers costing over $100,000.  Of course, they argue that money isn't everything, which is true, but it's a real shame that for $100k you still can't afford to buy a speaker with the absolute best tweeters in the world. You get one that is not bad, but not the best. 
  • One famous French speaker maker adds parts to the crossover to make it more "discerning." The parts do almost nothing to the response of the speaker, but makes it a much more difficult load. Reviewers and audiophiles swoon and say "oh these speakers are able to tell the difference between all of my amplifiers." Well, of course they do, if a 4 Ohm speaker becomes a 2 Ohm speaker only the heftiest of amps will be able to deliver good bass. UGH!  I'm very happy to say that the LM-1 is NOT discerning, it is not a needy speaker. It will play well with every amplifier.  If you need lessons in snobbery, go to the French (speaker makers that is).
  • Diamond drivers: Most expensive, but no guarantee of being the best sounding. AMT, ribbon and beryllium technology easily surpass the most popular diamond tweeters out there.  However, the type of driver is only part of the equation. The motor structure, suspension, crossover and application to a particular need are equally big factors, so don't be impressed just by a technology.
  • Dipping the frequency response around 2.4 kHz to create an exaggerated sense of imaging. Used on both sides of the Atlantic.

Buying Great Sounding Speakers

As I've written before, the "High End" speaker industry consists mostly of the cynical selling to the gullible. How do you avoid these traps? Turn to my custom speaker making page, here.  It's far better to buy from custom makers or DIY speakers yourself than to follow the trends in vogue today.

Thursday, May 12, 2016

The Mundorf MA30 Anniversary Speaker Kit - In Theory

In case you're not familiar with it, the MA30 is a sealed two way speaker using one of the smallest Mundorf AMT19CM1.1C for $255 each mated with the 6.5" Accuton C158-8-085 which runs around $275 each. Given normal margins, if this speaker had a brand name this would be a $10,000 speaker for the drivers alone. With the premium Mundorf crossover parts you could easily drop another $2,000 to $4,000 on a comparable speaker system.  Compare that to the minimum full kit of $2,500 and you can see what a huge bargain this kit could be for you.


At the current time the speaker kit appears to only be available through Grant Fidelity. An e-mail from Madisound on May 12, 2016 confirmed they are selling the kit but do not yet have the web page for it online.

The speaker kits come with your choice of pre-assembled crossovers, all made by Mundorf. Not a brand to be scoffed at, they also provide the parts and assembly for several very high-end brands.

At the Munich 2016 High End Show, Gryphon and Kharma, two of the most expensive speaker brands there, included drivers from either Accuton or Mundorf. The MA30 has no reason to feel shy around either brand.

I personally have measured a larger sibling of the Mundorf AMT's and found it literally beyond reproach. Frequency response, distortion, and linearity (freedom from compression) of the Mundorf AMT tweeters is among the very best in the world, technically and audibly. You can spend more money, but you can't actually build a better tweeter, diamond or otherwise.  You can also get far worse AMT tweeters than Mundorf makes by the way.

Accuton also has a very strong following, and rightly so for their quality and technical advancements but not from this particular author.  Sorry, I don't find them that interesting compared to other driver makers. My personal tastes aside, I think this is a great kit worth promoting.  Like ANY speaker, it has to do oo-mox to your ears, not mine, and for many Accuton does just that.

In any event, it's time to get to the heart of this discussion. The title of this article says it all.  This is a theoretical analysis based on the driver measurements and crossover design as can be gleaned over the internet. I have not measured them directly, and am guessing the acoustical distance from the phase matching.

While I had a great time meeting Norbert Mundorf at the 2015 California Audio Show but the electronics, room acoustics and source material was out of our hands and I never had the chance to listen to these beautiful looking speakers in a good environment.

Still, we can say a lot about them based on simulations and parts.

The Crossover

You would be surprised how many manufacturers skimp on parts quality, as well as include tricks in their design to make speaker sound different, more exciting than they would otherwise. Some even go to great lengths to make the speakers hard to drive, so they appear to be more discerning, or deliberately mismatch the crossover points to leave a dip and enhance "imaging." And don't get me started on how many juice the treble one way or another.

So, let's talk about the crossover. Grant Fidelity lists specs that just can't be correct, so I'll put what are more likely true, based on published board designs:
  • Crossover point: 2.5 kHz
  • Filter types: 3rd Order
  • Driver polarity: In Phase
Based on the designs I have put together a crossover network, which I will not show here, but I did derive some frequency and impedance plots.

The frequency response is exactly what I would expect from an honest design. Below 2kHz it's flat to +- about 2.5 dB. After this there's a plateau where the response dips (a good thing) about 2 dB after which it's even flatter.

I would have dipped before then, but meh. The one bit of criticism, is that there is an overlapping bump in response at around 3.7kHz. The overall effect is small, around 2.5 dB. A notch filter could fix it at the expense of the driver phase matching which would have been a terrible trade-off indeed.

My point is, based on driver specs and crossover parts, its' a very solid crossover design without  tricks or gimmicks. Far too good a frequency response to appear in a magazine and a lot of so-called audiophiles probably won't like such an honest and well balanced speaker.

The Korean site Full Range has a write up on the MA30. Sadly among Asian languages I only can read a little Chinese but they do include what I presume is a measured frequency response. As you can see, it aligns closely with the simulation.


Of course, the other important factor is how easy is it to drive?

The answer is, it's pretty easy actually. The Accuton driver does have a very high peak. This simulation does not adequately simulate the cabinet effects, but if this peak remains, I would consider putting a 60 Ohm resistor across the inputs if driven by a tube amplifier. It will help keep that impedance peak normal. The minimum impedance (above 20 Hz) is 4.6 Ohms at around 1.2 kHz, not a place where amps usually have to huff and puff.

Conclusion

The MA30 kit has top quality parts everywhere. The makers are making money by bundling as a kit, but it's a pittance compared to what a branded, pre-built speaker would cost. The bass is going to be exactly what you expect from a small speaker. The MA30 will need reinforcement and a subwoofer to be close to full-range. However if you are good with that, you are going to have a very difficult time finding any speaker under $10,000 with these drivers and crossover components. If you listen to them and like them, get them, they are an absolute steal and a great start to a high end system, not to mention speaker building. The $300 crossover upgrade makes this an incomparable bargain.

Judge the value with your own ears but do not listen to them in haste. These speakers do not run to impress anybody. There is no fake modesty, blushing or seductive batting of the eyes in this design. Listen, breathe deeply and take your time to discover their sublime talents.

A Top Tier Alternative

For about the same amount of money, an alternative speaker kit is the Klang-Tong NADA design runs around $1,800 for parts plus $800 for cabinets from Taylor Speakers. Price and parts quality are comparable and both are available with pre-built crossovers. I personally prefer the ScanSpeak woofer to the Accuton, but I'm completely in love with the Mundorf AMT line, so I would say it's a bit of a toss-up. The Scanspeak will be warmer, and have more bass, it's also a much larger cabinet which is hard to tell from the images. Also, the dome tweeter has better dispersion.  Best for listening in well treated rooms, or when you need your stereo speakers to serve as background listening in addition to critical listening. If you need a full-range speaker and have the room for it then it's no contest. The NADA is  your top-tier speaker kit.

A Bargain Alternative

The MA30 and NADA  speakers are all expensive, and to many out of reach, so if you are looking for a well balanced speaker that costs under $500 / pair to build please consider the LM-1 speakers. They share a similar tonal balance to the MA30, but of course use much less expensive drivers, and can be built using off-the-shelf cabinets.