Review of Dartzeel NHB-108 Amplifier

Any multi-strand braided cable is going to have some amount of smearing to it, but my thoughts are that Cinematic's system isn't anywhere near up to the task of critiquing Jena's cabling.

First of all, the Behringer pieces have a very distinct "SS" and / or "digital" signature to them. That is, they sound sharp, sibilant and somewhat tizzy. There are modifications that one can perform to reduce these problems, but they don't completely remove the effect. Using more revealing cabling will only make this sonic trait more noticeable.

The little Yamaha multi-channel amp isn't exactly a "world class" performer either. Nothing like tinned conductors housed in a cheap plastic ribbon cable within the signal path to clobber high frequency resolution and system transparency. This is yet another factor that could lead to an "edgy" sound, which more revealing cabling would make more noticeable.

As a side note, i've commented many years ago about the sonic potential of the older Yamaha amps, primarily the M-80. In a head to head comparison driving 82 dB 2-4 ohm speakers, the Yamaha obliterated a similarly rated Bryston in every respect. As such, i've got nothing against "mass produced" gear that sounds and works good, especially when it can be bought for a very reasonable price and easily upgraded. In stock form though, these amps are not on the same playing field as many other amps that i've heard and / or owned.

Other than that, the darTZeel doesn't look to be a suitable amp for low impedance, low sensitivity speakers. As i mentioned over at AA, it doesn't measure all that great ( for multiple reasons ), but i'm sure that it sounds very nice. My guess is that the mids are extremely liquid sounding with a great amount of air and separation in the treble region. I'm basing this on the design parameters and quality of parts used, not on an actual listening session.

To me, Hooper's system looks like he's been a regular customer of Mr Tinn's, who is a dealer for most every brand of gear that Hooper is using. I could be wrong about that, but Mr Tinn's shop is located in the Washington, which is on the west coast, so that also fits that criteria. It would also explain Hooper's lack of willingness to divulge the specifics of which dealer he was working with. The fact that Mr Tinn is the distributor for this amp and was quick to defend Hooper's choice in gear almost makes one think that this thread was set-up by Mr Tinn to capitalize on the positive review / massive exposure that the darTZeel recently received in Stereophile. Then again, i could be wrong about everything here and this might just be another one of my conspiracy theories. Do the math and see what figures you come up with.... Sean
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"Cinematic_systems: I know you are a dealer and you should disclose this in your posting". Jtinn

"Sean: You must be kidding. Haven't we been down this road before? I really think you should rescind your statements and let sleeping dogs lay". Jtinn

Jtinn: You chastise Cinematic Systems for not disclosing that he is a dealer, yet you do the same thing with most every one of your posts. On top of that, the name that he posts under pretty much gives away the fact that he's a dealer while the use of your personal name doesn't. Unless someone is VERY familiar this forum, is an industry insider or read your reponse to the darTZeel review in Stereophile, one would assume that you were simply a normal joe rather than an industry professional that was directly involved with the productS ( darTZeel, Tenor ) being discussed. As such, fix the blatant holes in your glass house before you start condemning others for having leaky windows.

On top of that, i think that this has been discussed and dealt with over at AA. Why it is still taking place here at Agon, i don't know. From what i've been told, your "planted customer responses" weren't welcomed at AA and you were told that this wasn't acceptable behavior from a dealer.

Once again, i would request that Agon set up some type of identification program for dealers, distributors, manufacturers, reviewers and other industry professionals. While many industry professionals identify themselves on every post and / or make their affiliations known as the situation arises, some lack the scruples and / or self-discipline to do so.

As mentioned, not everyone knows who's who in the industry and there are new people joining the various audiophile forums day by day. This would allow them to sort through the potential hype of someone trying to push a product for monetary gain and / or benefits as compared to an avid enthusiast who is simply sharing their thoughts / ideas / experiences with no financial gains or risks to be had. Why Audiogon won't install such a system into the forums, i don't know. It's surely been discussed long enough and many enough times to know that it is needed. Sean
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Jtinn: I have publicly described how a product will sound and / or respond based on electrical measurements that i've seen. On more than one occassion, folks that have owned or used these products have confirmed those comments at the time of posting. Others have come to agree with them after familiarizing themselves with the product over a longer period of time. There is no magic involved, it is strictly a matter of applying science and logical deductions to the specifications gathered through standard testing procedures. This is also why i've repeatedly stated that specifications can tell us what a product sounds like, IF the spec's were accurately obtained and there are enough of them to formulate a theory on.

Other than that, i've only ever chastised you about your lack of disclosure about your being in the retail audio business and promoting some specific industry affiliated products. Nothing more, nothing less. Most of this took place several years ago when you first got in the business, but failed to publicly acknowledge that your avocation had changed. If you see it as anything more than that, you are delusional.

I couldn't care less about who you are or what you sell. I only want those that read posts submitted by those working within the industry to know that the opinions expressed within those posts may have specific motives for saying what they do. From there, an intelligent consumer can sort things out for themselves. If a person, regardless of their affiliations, consistently submits quality material that is both helpful and non-manufacturer specific to these or other forums, nothing that i could say or do could impugn their reputation amongst the intelligent group of consumers that frequent such forums. Sean
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Cinematic Systems is not trying to stir the pot, he's basically trying to ( reasonably politely ) comment on the design of Mike's room and the selection of gear. The fact that Mike has been dealing with Jtinn as both a dealer and consultant for the selection of gear obviously brings him into the equation. Jtinn's dismissal of Cinematic's comments and observations is directly related to trying to protect his own reputation as he tries to cast aspersions on Cinematic's reputation. Since i have nothing to gain by discrediting either point of view ( i am not a dealer as the two of them are ), here's my take on the situation. As is usual, this is simply my point of view and i try to remain as honest and impartial as i know how.

The size of the room will affect nodes, low frequency extension and spl capacity. Whether or not the speaker can effectively pressurize the room has to do with surface area that it has to offer ( size and excursion capacity of the drivers ) and the "loss ratio" of the room itself as frequency varies. It is possible to have a "rigid" ( non-lossy ) room at higher frequencies, but have it act like a sponge at very low frequencies. This would introduce a non-linear frequency response into what one hears, even though the system itself may be quite "flat" outside of room contributions.

Even though the physical size of the room may support the longer wavelengths that are created at lower frequencies without creating as many nodal related problems, the construction material itself may end up absorbing those low frequencies if they aren't rigidly anchored. The air-borne low frequencies are absorbed and converted into vibration within the construction material itself, which acts as a thermal loss. This reduces both the linearity of the room itself and the spl capacity that the room can sustain at lower frequencies.

If one was running a relatively "linear" system i.e. one that measured relatively flat, it would sound "weak", "thin" or "lacking in extension" in such a room. The end result is that one would need to create a non-linear sound system i.e. bass heavy in order to compensate for the non-linear absorption losses within the room itself. The end result would be a relatively flat presentation in this room, but in any other room, the added bass would be noticeable to one degree or another. That would depend on just how lossy the second room was at low frequencies.

The same things can occur in the mid and treble region with listening areas that are over-damped i.e. the need for a "hotter" sound to compensate for all of the high frequency losses within the room itself.

Obviously, this is a very tricky area and most rooms aren't actually "done" when the initial construction is finished. That's because reality often doesn't follow theory to a "T", so additional work is required in order for form to follow function with a closer relationship. Sean
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There are design aspects of the VR 9's that i really like ( sealed cabinets ), but for the money involved, i'm thinking that they could have made some very simple yet sonically important changes to them. The use of Solen caps instead of something a little higher grade, the 80 Hz crossover frequency for the single subwoofer driver, which is mounted on the rear of the cabinet, etc... are all things that i would have done differently. Then again, i'm not a professional speaker engineer, so what do i know. I just hope that Mike is happy with his purchase and that it delivers what he wants within the confines of his own personal listening room. He's tried damn hard to achieve absolutely phenomenal results and he deserves to get just that : )

I do have one question for Mike. That is, if he doesn't mind. I would be curious to see if he's applied any type of loudspeaker placement computer modeling to his installation? If so, how have the actual in-room results compared to the computer based predictions? Have you modeled the VR's to see how they'll work in this specific room? Sean
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Well, since i tried to be a "nice guy" and get back on track with my "calmer, more friendly" New Year's Resolution in previous attempts to reply to this thread, and they didn't make it through moderator approval, i guess i'll resort to the point by point response that i really didn't want to have to make.

Jtinn: Jenna's cables are based on a woven pattern. While the cables may present a consistent nominal impedance when measured at one end, the design geometry consists of multitudes of impedance bumps along the entire path of the cabling. The multitude of impedance variations is what makes up that nominal impedance and increases the potential for rejecting RFI. That's because one consistent impedance is easier for an RF signal to propagate itself upon / within, hence the multitude of impedance bumps making it tougher to pass an RF signal.

On top of that, impedance bumps create phase shifts, which in turn creates smearing. On top of that ( part II ), it is very difficult for all of the conductors within a mass produced multi-strand cable to remain the exact same length, giving the signal multiple length paths to choose from. This also increases smearing due to differences in arrival times. I could continue further with this, but no need to.

As far as speaker or product design goes, i don't have to build or market anything to have a basic understanding of parts quality and / or design theory and / or understanding on how instruments work and / or understanding on the room / speaker interface and / or the audible perception of various radiation patterns. What products do you design / manufacture to think you know so much? What technical and / or electronics credentials do you have to question my credentials?

As far as Solen's go, they are a great bang for the buck product. I don't think that anyone familiar with them would deny that. When compared to some other caps that shall remain nameless, the only reason that one would select the Solen's would be a matter of keeping production costs lower. The fact that the Von Schweikert website specifically mentions the use of Solen caps in the crossover led me to believe that they were the primary ingredient in terms of capacitors used, hence their trying to play up the use of a recognized "hi-fi" brand name. I didn't see any other brands of capacitors or inductors mentioned, so what would lead me to believe that others were used??? The fact that you said that there is ONE Solen used in the crossover circuit leads me to believe that this is either the only cap used, or that there are others used, but of lesser quality. If this were not true, i would think that they would have listed the names of the higher quality caps rather than settling for Solen as the "high end" buzzword.

As far as one woofer goes, a speaker of this cost using one woofer seems rather cut-corner to me. Since output capacity is directly related to driver displacement, one would think that multiple drivers would be a natural here, especially at this price range. That is, unless the designer thinks that one large diameter, long excursion driver is sufficient. The problem with that is that it is common knowledge that the more excursion that a driver has to make, the more non-linear the output i.e. distortion starts to climb. Using multiple drivers of the same surface area reduces the amount of excursion necessary, lowers distortion, increases maximum sustainable spl's, increases dynamic headroom, lowers thermal stress on each of the individual drivers, etc... If designed properly, a multiple woofer system can also load the room more effectively, therefore producing more consistent response.

As to the 80 Hz crossover, this is a bit high for use as a "subwoofer". The name "sub-woofer" implies output below the normal frequency range of a woofer. On top of that, 80 Hz is more easy to localize than if a lower crossover point were used. This has to do with the fact that a higher percentage of room nodes will be excited than if output were actually kept down low i.e. in the SUB-woofer frequency range.

As to the rear placement of the driver, the length of the signal path from all of the other drivers to the seated listening position compared to that of the "subwoofer" aren't anywhere near the same length. On top of that, please name one instrument that produces low frequencies and radiates them in the opposite direction of that of the listener with NO direct radiation towards the listener at all. Even a kettle drum or pipe organ will radiate some of the sound forward off of the stage. Without this frontal wave, all of these instruments would produce completely different attack and decay characteristics to our ears and change the timbre of the instruments as we know them and hear them.

Other than that, it is convenient of you to overlook some of the other things that i've said about you in a positive manner. Obviously, your attempt to portray me as being "anti-Jonathan Tinn" is a ruse to distract others from the real matters at hand. I don't care who you are or what you sell, so long as you represent yourself and the products that you push honestly.

As i've said before, i try to call them as i see them. My comments in this thread, and all the others that i've contributed to, are simply my honest opinions. If you've got a problem with that, that's your problem. If i've stated incorrect information in this or other posts, that's OUR problem. Please feel free to correct my mistakes as you see fit and make me aware of the corrections. I want to learn from my mistakes. That's pretty much the only reason i know what i do i.e. i've made a LOT of mistakes and learned from them in the past.

As i've stated before, my "mission" is to share, learn and educate, not mislead by posting misinformation. I've always tried to do my best and be as honest as i can, even if i've gone overboard on some points. I hope others can recognize my efforts for what they are. I'm not looking for praise, just mutual respect from my fellow audiophiles that take the time to learn and share with me as a group. We don't always have to agree to be friends or discuss matters in an open manner. Sean
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PS... Mike, i'm still wondering about my question pertaining to the computer modeling / room simulations of various speakers & speaker placements in your room. Have you ever tried this and compared the results in terms of perceived sonics vs predicted results?

I think that God is trying to teach me something / tell me to get off of the computer. After typing out a detailed response to both Metralla and Mes, i ended up losing the post again. While this is a problem with "buggy software", i'm taking it as a hint that i need to be concentrating on other things.

Best wishes to all. I'm out of here until i can get things ( both my life and computer ) a little more organized. It's just too frustrating to spend the time that i do trying to explain things to have it all disappear in a matter of milliseconds. Then again, life can be like that if you're not prepared. Besides, the weather is starting to break and i need some exercise : ) Sean
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Mike: Speaker design is a science more-so than it is an "art". While many in the design / manufacturing / distribution / sales / reviewing industries of "high end" audio would have you believe otherwise i.e. "the talented and very secretive audio guru's working their black magic", etc..., without the science, formula's and consistencies noted amongst specific design parameters, speaker design would be more "guesswork" than "art". As such, applying the science, formula's and commonalities amongst operating parameters is what makes up about 90% of the speaker design. The other 10% is finessing the variables into place to achieve the specific voicing / electrical characteristics that are desired.

Whether or not one agrees with the specific figures ( 90% / 10% ) i used, i don't think that anyone familiar with the nuts & bolts of speaker design will question the comments that i made to any great extent. That's because they've studied the science enough to know what to expect out of a product based on how repeatable design parameters are implimented, sometimes even before they hear the product itself.

The only real "catch" here is the "10%" that is art / magic, which can take a poor design and make it listenable, a mediocre design and make it more enjoyable than expected i.e. "a world beater that is greater than the sum of the parts", a good design and make it into something truly enjoyable, etc...

On the other hand, one can have all the "right parts" and a great circuit with a very poor implimentation. As such, that last 10% could kill what should have been at least a decent product.

The point that i'm getting at is that 90% of the equation starts with the design i.e. the consistent and repeatable performance characteristics that are predictable based on science and math. The finesse factor / how it is implimented is what makes the difference once all of the science / math have been implimented. In this case, most of the "science" is pretty straight-forward, hence the ability to describe specific sonic attributes and electrical characteristics onto it as a product. As i mentioned, what instrument radiates 100% of the sound that it produces away from the listener?

With that in mind, i'm not saying that you or someone else can't or won't like this speaker. What i am saying is that based on the money involved and the other design approaches that could have been taken, the end product seems to be questionable in both value and performance. Then again, most every "high end" speaker falls into that category to one degree or another with some being far more questionable than others.

As a side note, this is a 94 dB speaker according to Von Schweikert's website. The rating of 96 dB's only applies if the bass and treble boost circuitry are engaged. In effect, it looks like the active equalization circuitry ( fancy tone controls ) not only increases the average sensitivity, but also delivers the "big & dynamic" ( bright and thumpy ) sound that so many "audiophiles" seem to like. The fact that Legacy voices their products in much the same fashion shows that personal preference may be a better selling tool than accuracy and linearity are. At least with Legacy products though, you do get a lot of driver surface area for the money. In that respect, they are a "bargain" amongst "high end" speakers, even if they aren't anything close to what "high end" audio USED to be about.

Metralla: How do i know that this cable has impedance bumps? That's easy. I have eyes and know how to interpret what i see : )

Honestly though, much of the "science" discussed above that makes speaker design repeatable also applies to the conductivity and electric parameters of cable design too.

I'll try to keep this simple. A conductor in free space presents a specific impedance / velocity of propogation. Placing other conductive objects in proximity close enough to disturb or "couple" to the field produced by the conductor passing signal will change both the impedance and velocity of the signal.

Given that the cable design being discussed consists of a woven pattern, you'll have a conductor that is "somewhat" in free space and then that conductor is placed above / below / next to another conductor. It then hits an open gap in the weave and then is placed in close proximity to another conductor above / below / next to it. This produces a random yet repeated change in impedance until the end of the pattern.

Think of the electrons in the cable as a car and the woven pattern as traffic on an expressway. In some spots, the car can pick up speed as there is no impediment to flow i.e. open space all around it. Once it hits a pack of cars ( enters an "intersection" in the weave ), the speed of travel ( velocity of propagation ) has to be altered. Once the car ( electron ) makes it through the congested intersection ( areas where conductor cross section comes in contact or closer proximity with each other ), it can now procede ahead at full speed as there is a open area i.e. another "gap" in the traffic before it has to weave in and out of the traffic, slowing down progress once again.

When looking at the progress that the car ( electron ) made travelling from point A to point B, we can ascertain the "average speed" ( nominal impedance ) that it took. Only problem is, that average speed is a combo of both "open road" speeds and "heavily congested traffic" speeds, which equate to the different impedances, "electrical bumps" and velocities that the electrons encountered.

As to my vantage point, i'm in a helicopter flying overhead going directly from point A to point B. Not only can i see all of the changes in traffic flow ( impedance alterations ), but i've got a much shorter path since i don't have to weave around other obstacles, which requires me to alter my speed. Once again, this is why the shortest and straightest path is typically the fastest and most consistent route. I also new what to expect in terms of traffic flow ( impedance and speed of conduction ) as i had observed these characteristics many times before with both my naked eyes ( visible traits ) and by studying traffic logging data ( test results ). Knowing what to expect on any adventure and how best to deal with the variables involved can be rewarding in both time and monetary expenses. This is why educating yourself on the subjects that you'll be dealing with is both wise and enjoyable i.e. it pays for itself.

Hope this helps and made the explanation easy enough to follow. Sean
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PS... That explanation is pretty rudimentary, but it gets the point across.

Joperfi: Duke doesn't have this problem for very specific reasons. Duke plays his cards above the table for all to see in a most up-front and helpful manner.

Mike: I never said or meant to infer that you were a "stirrer of the pot". How you got that impression, i don't know. If you can point out how & what you interpreted in one of my posts as saying that, i'd love to see it so i can both correct it and learn where i made such a mistake.

To be quite honest, i meant what i said in your system thread. I also appreciate the amount of time and effort that you've invested in responding to questions about your room construction, system selection, listening comparisons, etc... I didn't know if you had seen my initial questions pertaining to room modeling, hence my bringing it up again. Then again, i also didnt' know if i was being blown off because i was publicly "lambasting" your dealer.

Jtinn: Since you called me to task on my lack of audio industry affiliations and design / product familiarity, i am looking forward to your expert and professional reply to the comments / explanations that i've offered above. I see that you've taken the time to respond to and applaud Howie's criticism of Cinematic Systems, yet you've failed to offer any further insight or technical commentaries as to other comments / criticisms being made in this thread.

If you wonder why others have commented on why you find yourself in the situations that you do, now might be a good time to reflect on the situation. Sean
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