THIEL Audio MCS1, SCS3 and SS2 Loudspeaker System Review

MCS1, SCS3 and SS2 Company Background

THIEL Audio Products Company of Lexington , Kentucky is a privately-held, engineering-driven organization that performs research, design, and manufacturing of loudspeakers. Their products incorporate a variety of unique technologies in driver design, acoustical construction techniques, and crossover design. Jim Thiel is a co-founder, co-owner, and product design engineer for THIEL. Jim pioneered the principle of time and phase accuracy in loudspeakers with the use of sloped baffles, coaxial driver mounting, and phase coherent crossover network design. Kathy Gornik, co-owner and President, is responsible for company vision, direction, policies, and marketing strategy. She oversees the appointment of all domestic dealers and international distributors, and is responsible for relations with the media and audio industry. THIEL Audio combines craftsmanship and unique technologies to manufacture each of their speakers. The process begins with careful selection of hardwood veneers from responsible foresters. The cabinets and finishes are machined with high precision CNC machining centers that provide tight tolerances and aid in creating their complex cabinet designs. The cabinets are then hand-assembled and finished to standards and procedures qualified for elegant furniture.

THIEL offers a broad range of finishes guaranteed to satisfy any tastes. They also offer custom finishes and optional grill cloth fabrics upon special request. Our review products were finished in dark Ebony, which wouldn't have been my first preference. I'd love to see them again in either Dark Cherry or Mocado both of which should certainly enhance the beauty of these cabinets.

Introduction

For many years I have revered the THIEL speaker cabinet designs and construction. Being a DIY speaker builder, I recognize their efforts on time alignment and minimization of diffraction which tends to be less common among the vast array of traditional speaker designs.

When I was asked by Audioholics Senior Staff if I wanted to review a THIEL speaker system, I received the news with enthusiasm and excitement, especially since I never had the chance to audition or closely examine their products before. I knew that by participating in such a review, I would now have the chance to thoroughly examine the quality of THIEL's loudspeakers. Once the necessary arrangements were finalized, the speakers were shipped in a matter of days and quickly integrated into Reference System 4. After my brief interlude, we later moved the system to our new Audioholics Interactive Home Theater (IHT) Center where we conducted our measurements and additional listening auditions with several of Audioholics Senior Staff.

Configuration and Setup

Our complete THIEL home theater speaker package included three MCS1 speakers for left-center-right, two SCS3 speakers for the surround channels and one SS2 subwoofer with Integrator controller. I first tried to set up the SCS3 surrounds on my current speaker shelves but they were a bit too heavy, implying that they were well constructed. Attempting to resolve this dilemma, we asked THIEL to send us their stands and within a few days we had the surrounds supported, set up and ready to audition.

The electrical connection for all speakers consisted of my all time favorite, easy to use design. The binding posts accepted dual banana plugs which made it especially easy to switch speakers during our comparative investigation.

After mounting the MSC1's to their respective stands, the combined weight made them a bit unmanageable for a reviewer working solo. I found that once these rock solid speakers were positioned, it's best to leave them be or if necessary, get someone to help reposition them later if required. The speakers were auditioned on Reference System 4 and IHT Reference System A (main system) thereby allowing us to do a more thorough audition.

THIEL MCS1 FRONT-LEFT-CENTER

• Drivers - 3-way system with 1" metal dome tweeter coaxially mounted in a 3.5" metal cone, short coil/long gap midrange; two metal cone, short coil/long gap woofers with copper pole sleeve and cast magnesium chassis; dual ported; magnetically shielded.
• Bandwidth (-3dB): 47 Hz-23 kHz
• Amplitude Response: 50 Hz-20 kHz ±2 dB
• Phase Response: minimum ±10°
• Sensitivity:  90 dB @ 2.8 V-1m
• Impedance: 4 ohms (3 ohms minimum)
• Recommended Power: 50 to 300 watts
• Size (W x D x H):
• Speaker Size 10 x 12.5 x 28.5 inches
• Speaker on THIEL Vertical Stand Size: 13.25 x 17 x 39 inches
• Speaker on THIEL Horizontal Stand Size: 31.5 x 17 x 20.75 inches
• Weight: 61-lbs

“One aspect of the design of the MCS1 is that it is time coherent at (nearly) all radiation angles and therefore time coherence is provided regardless of the height or angle that the speaker is positioned. (This is an absolute technical requirement for all our non floor standing speakers.) Achieving this was a at the heart of the MCS1's design and is made possible by the fact of the speaker is a 3-way, and therefore the crossover point from the woofers can be low enough to preserve the "virtual woofer" performance through the operating range of the drivers.”

During installation in Reference System 4, I placed the MCS1 front and left speaker to the inside of my DIY reference speakers making them about 8 feet apart. The mains were positioned about 2 feet out from the front wall while the center speaker was against the front wall. The Integra Research RDC-7 was adjusted to compensate for the difference in distance between the main and center speakers from the listening position.

Editor Notes:
Placing the center speaker against the wall may have had two unintended consequences:

• Depending on how close the speaker was to the wall there would be a dip in approximately the 360Hz to 440Hz range. This range is critical for vocal intelligibility.
• Close wall proximity would also boost the frequencies below 360Hz possibly adding an chestiness to the vocals.

Ken states that his screen is mounted fairly high on his wall. So placing the left, right and center in vertical orientation (and moving the center more forward, away from the wall) should yield ideal lateral sound pans with matched-timbre spectral balance.

MCS1, SCS3 and SS2 Speaker Design

The stands for the SCS3 surround speakers happened to be placed at ear level for the lower front seats. I set them up near the corners at the back of the room and towed them slightly inwards. 

Another commendable design concept from THIEL Audio was the implementation of large radius curves located on the front baffels of the MCS1s and the SCS3s. I once read in one of my speaker design books that small radius curves on a front baffle has insignificant impact to the tonal quality of the speaker however a large radius of about 4 inches can actually help reduce the diffraction from the edge of the cabinets for mid and high frequencies. THIEL Audio has been applying this design concept to their designs at least as long as I have known about the company. Since the MCS1 is a MTM (midrange-tweeter-midrange) design it is quite difficult to keep a large radius curve on the front. To solve this physical limitation, THIEL created moon shaped sides resulting in a larger radius near the drivers along with a 3-inch thick front baffle.

The thick front baffle combined with 1 inch thick side and back panels and excellent shelf-type bracing all made from MDF (medium density fiberboard) make this cabinet solid and formidable.

Giving the speaker a simple but revealing knuckle revealed that none of the panels showed signs of drumming or vibration. Having no cabinet vibration is crucial as to not color the sound during playback and THIEL seems to have taken care of this problem quite well.

The mid/tweeter chamber was completely sealed although I could not see what material was used for this sub-enclosure. We had several technical questions which we posed to Jim Thiel including this about the sub-enclosure:

"The walls of the mid/tweeter's sub-enclosure are made of a round tube of compressed paper that is a little more than a quarter inch thick. The round cross sectional shape gives this enclosure very high strength and non-resonant behavior."

MCS1, SCS3 and SS2 Design and Setup

THIEL MCS1 Front Grill

Prior to my audition, I curiously explored the sleek, tightly fit speaker grills. Upon thorough investigation I noticed that they were very difficult to remove. Once I managed to pry them off, I recognized that the grill frame was constructed with a semi-flexible aluminum frame that is made to slide very firmly around the front of the speaker. Once wedged back on, I discovered why the grill cloth draped tightly around the front baffle. This method minimizes diffraction caused by the speaker grill thereby allowing purists to leave the grill on during their critical listening. The THIEL grill design is commendable.

THIEL SS2 (formally called SW1) Subwoofer

• Powered subwoofer with two 10" metal cones
• Short coil/long gap woofers with 2.5" diameter voice coils
• copper pole sleeves
• 20-pound magnet structures
• high excursion suspensions
• cast aluminum chassis
• optional companion SC1 Controller

Thiel SS2 Subwoofer Amplifier Specifications:

“…the settings actually alter the frequency response of the subwoofer to compensate for the frequency response changes caused by the reinforcement and reflection of the nearby wall. This compensation allows the energy put into the room to be essentially the same as it would be without the nearby walls rather than being greatly altered by the wall effects.”

Editor Notes:This form of boundary compensation is usually found on bi-amplified 6” or 8” two-way studio monitors. The compensation usually has a “shelving” characteristic which means that it affects all frequencies from a certain point down(i.e. 80Hz). The reason to do this in a two-way studio monitor is to prevent excessive bass boost which would tend to color the vocals, and frequencies typically below 2KHz, which are handled by the woofer in these bi-amped designs. To apply this logic to a subwoofer means that you are abdicating substantial amounts of “free” boundary proximity gain and asking the woofers themselves to perform all the bass duty. Granted, the substantial “free gain” of common subwoofers often leads to a peak at some frequency below 100Hz but there are several subwoofer systems on the market today which incorporate at least a single band of parametric equalization which allows the system's response to be relatively flat while in a corner and still enjoying the benefits of passive, free room gain.

SS2 Subwoofer Setup

MCS1, SCS3 and SS2 Measurements and Analysis

We concluded our audition with measurements of the MCS1 and SCS3 speakers.  The results of the measurements are in correlation with our listening audition thereby allowing us to provide subjetive and objective feedback on the THIEL Audio Speaker System.

Measurements & Analysis of Thiel MCS1 Speakers

The MCS 1 had an overall uniform frequency response with a slight de-emphasis (-5dB from 3kHz to 7kHz) and a tad too much emphasis on the top end (+5dB above 13kHz ) with a -3dB roll off around 20kHz. The null at 89Hz is likely due to measurement/room interaction since this was not taken in an anechoic chamber. Off axis response was excellent and did help tame the top end a bit indicating that little to no toe in is preferred for a more flat frequency response. Usable bass energy was present to about 38Hz or so, but we still recommend crossing over these speakers much higher (say 80Hz) to increase system dynamic range and provide better bass integration with the subwoofer.

Notice the 89Hz null is gone at the listening position (3 meters) indicating it was likely do to measurement/room interaction rather than loudspeaker design deficiency.

This measurement was taken with the MCS1s set to full range with no subwoofer. The suckout at 50Hz is again likely a room node issue relative to speaker/listener placement. By crossing these speakers over and optimally placing the sub, much better bass integration and extension was achieved.

Measurements & Analysis of Thiel SCS3 Speakers

The SCS3 had an overall fairly flat response as well (similar to the MCS1) except the tweeter was again set too high (up to +7dB from 12kHz to 18kHz) with excellent extension past 20kHz. Again we see the same 89Hz suckout due to measurement/room interaction. The SCS3 had usable bass extension down to about 44Hz, but we again advise to cross this speaker over much higher to preserve dynamic range, especially since we found this speaker a bit lacking in this regard.

Q&A; with Jim Thiel on Internal Wiring of Speakers

During our review of the THIEL Audio SCS3 system, we pinged designer Jim Thiel on some technical questions regarding the loudspeaker designs and the choice of internal wiring and crossover topologies he employed in the speaker designs.  With his permission, we captured the interview which oddly focused more on the topic of cables than it did loudspeakers as can be seen below.

Italics = Jim Thiel's commentary and responses

Normal text = Audioholics Responses

Jim Thiel:
For the internal wiring we use a custom-made wire that is a solid, 18 gauge, oxygen-free, Teflon insulated, twisted pair that I think sounds best and I will try to explain why by first explaining some things about amplifier cable. It is necessary that amplifier cable have very low electrical resistance for two reasons. The first is that any resistance will cause a loss of power, the degree of which is determined by the impedance of the speaker. If a speaker has lower impedance then the cable's resistance will be a higher proportion to it and therefore "use" a higher proportion of the amplifier's total power.

Audioholics:
I agree cable resistance is paramount and should be kept minimum. That being the case, why not use a lower gauge wire, say 10AWG to further reduce DCR? I don't think it will matter much for a few feet of internal wiring, but since you make a case for it, please refer to the AWG Table below. This is for Solid Core Wire, Stranded wire is slightly less because of higher cross sectional area.

Note that 18AWG wire has over 6 times the DC resistance of 10AWG. Thus for amplifier cable runs of say 20ft of 10AWG wire (not considering LC losses) we have about 40mohms of DC resistive losses (below 50kHz - as AC resistance does double due to Skin effect), thus total loss across a 4 ohm load would be 20*log(4/(4+.04)) = .086dB - hardly significant.

Jim Thiel:
I am afraid I was not sufficiently clear. In the above I was first explaining some things about amplifier (-to-speaker) cable, as contrasted to speaker (internal) wiring. I was discussing the importance of low DCR in amplifier cable so that when I later explained why very low DCR is not required in our speakers it would not be thought that I was making that claim for amplifier cable. (For example, if the cable has 4 ohms of resistance)

Audioholics:
What cable has 4 ohms of resistance? Even 20ft of 18AWG only has 260mohms of resistance!

Jim Thiel:
Of course no cable has 4 ohms resistance. It is just a convenient value to use for illustration. and the speaker has 4 ohms of impedance, then the cable would use up half the amplifier power.) Now, in practice, a bigger problem than the loss of power, which is usually not more than 1 dB, is that since the speaker's impedance is (maybe quite) different at different frequencies, the power used up by the cable will be different at different frequencies. This causes the frequency response from the speaker to be altered by the cable's resistance, with very little reduction at frequencies that have high impedance and greater loss at frequencies where the speaker's impedance is low.

Audioholics:
True but again even the few feet of 18AWG wire internal in your speakers adds about 40mohms of resistance. If the driver impedance low point is 4 ohms, this represents 20*log(4/4+.040) = .086dB add that to the 20ft of 10AWG speaker cable and you get about .17dB of resistive losses which are still insignificant and really not worthy of debate.

Jim Thiel:
Well, you may be right that .17dB is insignificant. I do however believe that even this small amount of inaccuracy is audible under some circumstances and in fact I spend a great deal of engineering development time reducing response errors that are of this degree.

(By the way, this is one of the reasons we use additional components in our crossover networks which are not in the signal path but are for the purpose of evening out the impedance so that cable losses will be uniform at all frequencies and the response will not be altered even if the cable's resistance is significant.)

Audioholics:
This is an interesting goal, one that would certainly be advantageous when using high resistance exotic speaker cables. I would like to see how this works if you would so kindly share a schematic for it.

Jim Thiel:
The sub circuits added are usually one or two of either a series connected capacitor and resistor or a series connected capacitor, inductor and resistor. These series circuits are added across the input terminals, in parallel with the speaker. The first circuit can correct an impedance that rises at high frequencies and the second can correct a hump in the impedance.

Audioholics:
What you are describing here is a classic Zobel network usually used to flatten out impedance of a speaker to counter the rising impedance of a tweeter voice coil, or in some cases to restore amplifier phase margin and increase stability for heavy reactive loading due to an exotic cable or complex impedance of a speakers crossover. This is a fairly standard practice but I fail to see how this will uniformly counter resistive losses due to cabling. My advice here, if you think it is of concern, is to use heavier gauge wire internally in the speaker cabinets and recommend consumers to use heavy gauge speaker cabling (say 10-12AWG).

Jim Thiel:
The second reason amplifier cable resistance needs to be low is to avoid significant intermodulation. Intermodulation is when the signal to the woofer affects the signal to the tweeter, or vice-versa. Since current that will be directed to the woofer by the crossover network will cause a loss in the cable by its resistance, the tweeter will "see" this reduced input also. So at frequencies that are reproduced by both drivers, there will be distortion produced in one driver by the current used by the other driver.

Audioholics:
Again I don't see how cable resistance in a decent 10AWG speaker cable would be detrimental. What you seem to be describing is back EMF, which can be more problematic with series crossovers than with parallel networks, see:

Jim Thiel:
Well, again, I agree that this will not be a problem with amplifier cable of sufficiently low resistance. And again I am just explaining why amplifier cable resistance needs to be low; why, say, 4 ohms is not sufficiently low.

So for both these reasons we need amplifier cable to have low resistance and the most straightforward way to get low resistance is to use a large gauge wire, but this causes a practical problem in that the wire gets very stiff and unbendable. Therefore stranded wire is used but this causes sonic problems because the current will pass from strand to strand and encounter non-linear, distortion producing extra resistance.

Audioholics:
Non linear distortion in a cable? We haven't found this to be true after extensive testing and calculations. This has been an unfortunate fallacy promoted by many exotic cable vendors for years, whom incidentally offer no measurable or analytical proof to justify these types of claims. I realize Thiel supports many high end dealers who sell exotic cables that market this fictitious claim, but you may wish to reconsider making such a declarative statement about this, especially in light of the inarguable proofs we offer rebuking this in the following articles:

How does strand interaction produce extra resistance? I don't understand.

We realize many exotic cable vendors buy solid core wire in bulk from manufacturers such as Belden and therefore attempt to rationalize its superiority by introducing pseudo sciences, but please realize over the past two years we have written extensive articles about cables, while demystifying many of the snake oil claims.

Please see: Cable articles

As a result, consumer awareness about cable snake oil is at an all time high. It would serve all manufacturers best interests to be more objective about cables and not support baseless claims to server dealer sales of exotic cabling. We have nothing against solid core wire, or expensive cables for that matter, providing that the manufacturer claims aren't without merit. As a result, many legitimate cable vendors advertise on our site and others have even updated their literature to be more factual-based on provable cable theory.

Please note our contributing staff (in addition to myself) includes a list of field experts such as Dr. Howard Johnson, Henry Ott and engineers from Wayne Kerr - a Leading Test Equipment Manufacturer

Jim Thiel:
A "fix" for this is to separately insulate each strand but then you can have the problems caused by poor dielectrics (insulators) since good dielectrics cannot be made very thin.

Audioholics:
What defines a good/poor dielectric for speaker cables? You may wish to review our article on this topic. Other than serving the role of insulation and controlling cable capacitance,cable dielectrics really serve no other role on speaker cables, which will influence measurements or sonics.

Jim Thiel:
I agree that much of the promotional claims about amplifier cable is baseless and/or misleading and also that much high end cable is overpriced (sometimes drastically) in terms of performance. However, I believe that some cables do have detrimental effects on sound quality that are not explainable by resistance or inductance. Whether these almost always subtle distortions are caused by dielectrics, oxidation, bi-metal plating, etc are not determinable by me. But of course that something cannot be proved doesn't mean it does not exist.

Audioholics:
Again I encourage you to review the article we authored on cable distortion. It clearly demonstrates there is no mechanism responsible for causing non linear distortions in wires. If there were, don't you think a credible source such as IEEE or experts in Electronics Fields and Waves experts would have authored a paper on this? The only folks touting cable distortion are exotic cable manufacturers and supplementary cable forum cult hobbyists.

Jim Thiel:
So, with this background, we come to internal speaker wire. What we do is, first, internally bi- or tri- wire all our speakers. This means that we have completely isolated the electrical current in the woofer circuit from that of the tweeter; there are no wires, even ground wires, in common between drivers, beginning right at the input terminals. The benefit of this isolation is that there cannot be any intermodulation, no matter how high the resistance of the internal wiring is. The next thing is to realize that, since we have eliminated intermodulation as a problem, low wire resistance is no longer necessary at all because the losses caused by resistance of the short lengths of internal wire is low and because any such losses can be corrected by adjusting other elements of the speaker's design, like crossover component values, driver magnet size, etc. In other words, we can engineer the speaker to have the correct response taking into consideration the small amount of resistance of the internal wiring.

But why would we bother having to take this into account? Why not just use larger, stranded wire? The reason is that by using smallish solid wire we can completely eliminate any distortions produced by stranding and/ or their insulation.

Audioholics:
Again you may wish to reconsider this viewpoint since it lacks any scientific proof, merit or credibility. There is no proven distortion mechanism for wires. Using the best test gear on the market (Audio Precision 2) we have demonstrated no nonlinear mechanism exists for this to occur. If it did, how would engineers design sensitive test equipment, space probes etc if their wires were causing so much distortion? Even if measurable wire distortion did exist, it would not even be a 1/100 th of the magnitude of distortion induced by the drivers or circuit components. Wouldn't you agree?

Jim Thiel:
Yes, I would agree that wire distortion would be 40 dB lower than usual driver distortion. (But we have reduced that by a factor of 10 also.) But even so this would not ensure that such distortion was inaudible. I don't care much if something is proven or not since my solution is of low cost. As I mentioned earlier I do believe there are sonic effects that I don't know how to measure and since I can eliminate this possibility for very little cost, I don't see why I would not do so.

Audioholics:
Wire distortion 40dB lower than driver distortion!?! That's news to me. If this were true surely a simple measurement would demonstrate this. Again I defer you to an article we already conducted thorough testing of wire distortion for a wide assortment of cables and found nothing.

Cable Distortion

Let's figure a usual driver distortion of 1% or -40dB. If we look -40dB lower than that for cable distortion, we would need a resolution of -80dB. Please note that the accuracy of our test contained resolution of greater than -120dB (.0001%) or over 100 times more precision than required, and certainly more resolution than even the best audio systems could provide, yet no presence of wire distortion was found.

Jim Thiel:
We need only one layer of insulation which can be of the best type, Teflon, without worry that the thickness of the insulation will be a practical problem. So we can choose the best sounding wire, which is smallish solid wire, without having to accept any compromises caused by (a little) higher resistance.

Audioholics:
Again I don't see how you can conclude the "best sounding" wire for a few feet of internal cabling of even the worst (18AWG wire). I assume this is merely a statement of opinion.

Jim Thiel:
Well, I have tried to explain why, in our speakers, even ten ohms of internal resistance would not cause any sonic problems other than sensitivity loss, how we wire our speakers to eliminate the possibility of other subtle factors having a negative effect on the sound, and how we can achieve our objectives without spending a lot of money that I feel is better spent on better drivers or cabinet.

Audioholics:
Ok so what you are saying is that the consumer can use any type of wire, stranded or solid core, 10AWG or 22AWG and still expect excellent performance with perhaps some loss in sensitivity when higher gauge wires are used. So why are we having such an involved discussion on wires? :-)

Jim Thiel:
Well, this had been a very long answer, and probably more than you wanted to know, but I hope it answers your question.

Sincerely,

Jim Thiel

MCS1, SCS3 and SS2 Listening Tests and Conclusion

The Score Card

The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:

Performance × Price Factor/Value = Rating

Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.

Audioholics Rating Scale

• — Excellent
• — Very Good
• — Good
• — Fair
• — Poor

Metric	Rating
Build Quality
Appearance
Treble Extension
Treble Smoothness
Midrange Accuracy
Bass Extension
Bass Accuracy
Imaging
Soundstage
Dynamic Range
Performance
Value