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Accugroove site update.....

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#82
Petebass said:
Doing so requires access to the products themselves, and accurate measurement systems. Mark Reccord and I have already said we're happy to do the testing, but where on earth are we going to get access to every speaker cab and raw driver ever made? Assuming access t equipment is somehow overcome, imagine the enormity of such an undertaking.

And unless we can somehow nail everyone at once, all we'll do is put people out of business one at a time at a slower rate than the new companies that come along to replace them.

Until then, Caveat emptor!
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I've mentioned it before, but this board represents a good deal of buying power. Maybe what's needed is a "TB seal of approval". In some industries manufacturers actually fund to have their product tested by a watchdog organization. Like for example THX. Maybe it's time for TBX :ninja:
 
#83
SMASH said:
I disagree. IMO the way they've responded to this is a least as damning as the proof that the switch doesn't alter impedance.
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I agree with your disagreement (sorry for going Danny Kaye) that his silence and removal of the fake switch from his product and the false claims in his ads are quite damning but from Mark's point of view he has a backfired scam to control. Anything he says in his defense will just be more hogwash that will lead to more chatter and less money for him. The cynically correct and profitable move is to say nothing and let the fan club play Johny Cochran for him and hope our short attention spans won't interfere with the next marketing campaign. A small group of overzealous naysayers on the net can be ignored as those that hate our freedoms or whatever and business can go on with the next scam.

I find his actions consistent with someone who was knowingly fraudulent. Others may prefer a more hypothetical rationalization.

P T Barnum said:
You'll never go broke underestimating the intelligence of the public!
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#84
Petebass said:
The only problem with this judgement in the speaker industry is that they'll all end up being nailed to the wall. The speaker industry is rife with false advertising.
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Only because the public, instead of demanding truth, viciously defends the right to lie of their favorite products. Acme gets respect for being honest with the downside of his designs, I think we should encourage more of that.
 
#85
Petebass said:
Doing so requires access to the products themselves, and accurate measurement systems. Mark Reccord and I have already said we're happy to do the testing, but where on earth are we going to get access to every speaker cab and raw driver ever made? Assuming access t equipment is somehow overcome, imagine the enormity of such an undertaking.

And unless we can somehow nail everyone at once, all we'll do is put people out of business one at a time at a slower rate than the new companies that come along to replace them.

Until then, Caveat emptor!
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I think if companies start seeing consumers demanding honesty a few examples can have a ripple effect throughout the industry and society as a whole. For example notice the recent criminal guilty plea of Jack Abramoff naming one politician has caused dozens of them to quickly clean up their act.

While we can't go to fully perfect overnight we can write letters to Bass Player telling them how much we appreciate their investigative reporting and encourage more or similar acts. How much lying advertisers give us is directly related to how much we'll take.
 
#86
Mark Latimour said:
The point was not that people are ripping into them for deceptive practices, but that a lot of people are cutting Accugroove slack which they would not cut if this were a Fender or a Behringer.
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Oh, I think I just read it wrong then :)

And as for as this witch hunt notion, if Accugroove made a false claim about they're product, you can hardly blame people for wanting the to suffer the consequences.
 
#88
Speaking of misrepresentation, I heard a rumor from a reputable source that EA was fudging on the impedence of their cabs to try to get the output performance up to compete with others. This was supposedly found out by running 2 8 ohm(supposedly) NL210 cabs into another manufaturers head rated with a minimum load rating of 4 ohms and they shut it down due to low impedence. Anybody heard about this?
 
#89
Reefer said:
Speaking of misrepresentation, I heard a rumor from a reputable source that EA was fudging on the impedence of their cabs to try to get the output performance up to compete with others. This was supposedly found out by running 2 8 ohm(supposedly) NL210 cabs into another manufaturers head rated with a minimum load rating of 4 ohms and they shut it down due to low impedence. Anybody heard about this?
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There's more than one way to get an amp to shut down.

Again, an impedance sweep will put it beyond doubt. Are any NL210 owners prepared to let myself or Mark Reccord run a test on their cab?

What does an impedance curve for a transmission line cab look like anyway? I know they share the same 12dB rolloff as a sealed cab, but does that mean the impedance curve will be a single hump like a sealed cab?
 
#91
Petebass said:
There's more than one way to get an amp to shut down.

Again, an impedance sweep will put it beyond doubt. Are any NL210 owners prepared to let myself or Mark Reccord run a test on their cab?

What does an impedance curve for a transmission line cab look like anyway? I know they share the same 12dB rolloff as a sealed cab, but does that mean the impedance curve will be a single hump like a sealed cab?
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I was told an impedence test was done verifying the cabs were well below the published impedence, but I'd like to hear from someone here to verify it also.
 
#92
Petebass said:
There's more than one way to get an amp to shut down.

Again, an impedance sweep will put it beyond doubt. Are any NL210 owners prepared to let myself or Mark Reccord run a test on their cab?

What does an impedance curve for a transmission line cab look like anyway? I know they share the same 12dB rolloff as a sealed cab, but does that mean the impedance curve will be a single hump like a sealed cab?
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It's a dual hump but the humps are muted compared to those of a conventional vented box.

...And yes, I'm dead serious that I will run measurements on any cab if anyone wants to send me one.... I would sign a contract to cover any damage and cover at least one way shipping. I'm pretty remote though. :(

I do think that manufacturers do need to be held accountable, especially under circumstances like this. That goes for Accugroove to Zon.

Oh, and I saved at least $1500CAD. The check's in the mail...:D

There's not much else I can say other than this is the longest thread I ever started. :D
 
#95
Mark Reccord said:
I thought the curve was saddle shaped in a T-line. Oh well, guess I was wrong...
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I have always been interested in learning how different cab tunings affect frequency response, etc. Regarding EA, here's the text from their site:

---The additional output provided by the transmission line is accomplished by modifying the cabinet impedance (load seen by the amplifier). The impedance of a cabinet varies with frequency. The nominal impedance is generally 4 or 8 ohms. This is the impedance of the cabinet at a fixed frequency (250Hz is a sensible frequency to use since it will give the same result whether the cabinet is a closed box, vented or a transmission line). The impedance of the vented 2x10 cabinet at 41Hz (open E string) is 11 ohms and the impedance of the transmission line 2x10 cabinet at 41Hz is 9 ohms. The cabinet volume and drivers are identical but the amplifier is now supplying 22% more power at 41Hz to the transmission line cabinet.

Finally, the Transmission line cabinets can be tuned over a broad spectrum where the vented enclosure is tuned over a narrow spectrum. Using the same two cabinets in the previous example, the impedance of the vented 2x10 at 31Hz (open B string) is 20 ohms and the impedance of the transmission line enclosure is 9 ohms. At 31Hz the amplifier is supplying 122% more power to the transmission line enclosure. This would account for the additional 4dB additional output that the transmission line cabinet has over the vented cabinet.---

I always wondered how this would impact the nominal impedence of their cabs. I ran one of their 4ohm VL210's in the past very hard with a head that is rated safely down to 4ohms with no problem... but the head did get quite warm.

Anyway, interesting stuff....
 
#96
I thought the curve was saddle shaped in a T-line. Oh well, guess I was wrong...
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You would only see that if you looked at the sweep of the entire range of the woofer. One way you can tell that a TL is properly done is that the impedance curve looks like a sealed box. The impedance does rise in the high end due to the voice coil inductance, but that's also where response falls off and where you generally will cross over to a midrange driver. But that's hi-fi.
Low impedance doesn't necessarily signify either higher sensitivity or extended response. The opposite can also be true. One of the reasons why horns have high sensitivity is that they are high impedance devices. A TLs impedance curve doesn't fully explain how it works, that's mostly a matter of its being a quarter-wave device. The EA quotes are less than 100% accurate, but that's understandable, as of all the alignments the TL is probably the least well understood, and as regards T/S specs was thoroughly quantified by Augsperger only some 5 years ago.
 
#97
billfitzmaurice said:
You would only see that if you looked at the sweep of the entire range of the woofer. One way you can tell that a TL is properly done is that the impedance curve looks like a sealed box. The impedance does rise in the high end due to the voice coil inductance, but that's also where response falls off and where you generally will cross over to a midrange driver.
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I was referring to the lower end of the curve. I thought I had read somewhere that a T-line's curve was sort of part way between a sealed and a vented curve and that there were two impedance bumps, but they were muted compared to a vented box. I understand the effects of coil inductance. ;)

I'll be the first to admit that I haven't studied T-lines thoroughly so I certainly stand to be corrected on the matter. I just had a look at some T-line sites and lots of them do exhibit a double impedance peak, but some of them do exhibit a single peak. I guess the textbook, well executed T-lines do this.
 
#98
Reefer said:
Speaking of misrepresentation, I heard a rumor from a reputable source that EA was fudging on the impedence of their cabs to try to get the output performance up to compete with others. This was supposedly found out by running 2 8 ohm(supposedly) NL210 cabs into another manufaturers head rated with a minimum load rating of 4 ohms and they shut it down due to low impedence. Anybody heard about this?
Click to expand...

Looking at the impedance curves for a given cab, there will certainly be a minimum impedance point that is probably notably lower than it's rated impedance. One question would be at what frequency does that minimum impedance occur, and over how wide of a segment of the audio bandwidth does it occur (okay, that was two questions). I would fully expect that an NL-210 rated for 8 ohms would have a minimum impedace (at some frequency point) of less than that. I know from my "audiophile adventures" that many speakers rated at a given impedance have curves that can vary quite widely from this figure.

And from what has already been posted, clearly the transmission line design comes into play as well, though others here are far better qualified than I to comment on this topic.

I have in the past discussed the impedance curves of EA cabs with John Dong, and I recall him saying something along the lines that a rule of thumb that they use at EA is that when a cabinet is rated by them as an 8 ohm cabinet, a pair of these cabinets will play correctly with a "well designed" amplifier that is performance rated to run a 4 ohm load. I have used my two NL-210's with a couple of heads rated to 4 ohm (Walkabout, Walter Woods and Thunderfunk) and I never had any problem (of course, I also tend to think that many "good" heads rated to 4 ohms can actually drive a lower impedance with little difficulty.

Once again, a look at the actual impedance curve would, of course, be helpful.

Tom.
 
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