agedhorse

Be sure that whatever cable you buy, it uses genuine Neutrik SpeakOn plugs. The cheap Chinese knock-off plugs are notoriously problematic, and the source of many frustrating problems out in the field.

Maybe, maybe not. It depends on what you are after with your tone, and if the (constructive/destructive) interference between point sources is a problem, or perhaps something that you actually prefer. A single vertical column still has constructive and destructive interference, it's just in the other plane and it may or may not be an issue as well. I remember when large flown line arrays first came into fashion, and the claims of no interference between cabinets was often touted as the biggest benefit. What many of these folks making these claims didn't understand is that the interference in the vertical plane is there and it's necessary for the line array to work as a line source. In fact this is the the basis for one of the two ways of coupling the mid and high frequency elements into the array... either each element has a narrow vertical pattern and they are all placed so that they overlap as needed for the coverage, or they are a wider vertical pattern and while they are guaranteed to overlap, they do so in a more gradual manner but with a little less control. The earlier cabinets with narrow vertical elements would lobe as you walked from the stage out to FOH, whereas in a horizontally arrayed point source system they would lobe as you walked horizontally across the auditorium. It's just 2 ways of dealing with the real world interference that occurs between any 2 point sources (no matter how they are arrayed). It also occurs with reflections off of boundary surfaces, at some point you can't do anything practical about it, it is what it is and you move onto more important things like catering and getting paid.

Respectfully, to counter the common argument that the polar pattern (response versus frequency versus axial angle) of a speaker depends only on the diameter of the driver and the spacing to adjacent drivers, this is only partially true. It is possible (and commonly done in the real world) to alter the polar patter of a driver at higher frequencies by changing the cone depth, shape and the size/material and location of the dust cap. All of these elements contribute to the non-theoretical aspects of a driver's radiation pattern, and is why 10 different 15" drivers will have 10 different polar patterns. As an extreme example, the JBL D-130 utilizes a shallow, light weight curvilinear cone, and an aluminum dust cap that is directly bonded to the top edge of the bobbin. This dust cap acts to radiate the higher frequencies differently that the cone itself. As another extreme example of what could also be called a secondary radiator, the "wizzer cone" concept is a dust cap with a radiation element that is bonded directly to the top of the bobbin and can extend both the frequency response and polar pattern by an octave or more. Polar patterns are something that designers consider when developing transducers for practical applications.

Oooh, and it has both slots AND triangles too!

Slot and triangular ports do not have to be an issue, again when designed with this in mind. The pro audio industry has used both for decades without any problems being described. The common theme is that designers using such ports design them so that they typically don't have an aspect ratio much over 1.5:1 depth to short leg dimension. These are products that have tens of thousands of pro touring shows under their belts, so there's no doubt that they have proven themselves many times over. I have used both types of porting as well, and haven't experienced such difficulties either. DAS: Community: RCF: JBL STX series: JBL ASB series:

Agreed, and in the case of the part failures we saw, we would have had to test hundreds for over 3 years because we didn’t really begin to see them for that period of time, and even after 10 years there was only a ~10% failure rate. Here’s a little data sheet that documents the qualification process and analysis that’s behind the basic process of reliability metrics. This covers known failure modes, at the time this failure mode (production issue) was not understood. https://dammedia.osram.info/media/bin/osram-dam-2496614/AN006_Reliability and lifetime of LEDs.pdf

Good perspective. Nothing is 100% risk free, and without taking at least a tiny bit of risk, everyone would still be playing uprights, acoustic guitar, etc. I don’t know if you remember when the high brightness, high temperature LEDs came out for traffic light applications, but they also had higher than acceptable failure rates that took several years to show up. This was in spite of extensive testing and qualification. This too was addressed in the upgraded parts and semi fab process. The average person would probably be surprised at the amount of effort that goes into maintaining reliability metrics in modern products. Unfortunately, no process is 100% perfect nor 100% thorough. To do so would put the cost of new products out of reach. It’s why commercial aircraft are so expensive, yet in spite of a level of qualification, traceability and testing that’s an order of magnitude higher than what’s used for bass amps, mistakes still happen and every aircraft manufacturer in the world has experienced it too.

Mark - it was YOUR accusation about the product design (amp design) being an issue which was not the case. It was a documented problem with the LED itself that was addressed when it was discovered. Of course it happened, nobody ever said that it didn't. It affected about 10% of the amps, which means that 90% of the owners never had any problems. That's what I have an objection to because it's factually incorrect.

It had nothing to do with the amplifier design, it was a defect inside the LED itself. Other manufacturers of products such as cars and appliances ran into the same issue with this part, and so did we on one product where the part was used as an indicator a (not for aesthetics). The replacement part did not have this problem. Yes, it was purely aesthetic. Many players liked the look and we chose not to make another simple, boring black box. Unfortunately, we were impacted by defective parts. We honored warranties on these LEDs all over the world, and I sent out replacement parts globally for almost 10 years at no cost as well (including to Basschat members who contacted us). Why do you have such negativity towards me, did I do something to you personally to deserve this kind of treatment? Actually, I have seen (and personally experienced) a general negativity and hostility here towards Americans over the past few years on Basschat. It's not welcoming, embracing or particularly friendly.

Actually, it wasn’t an amp design issue. The LEDs were an early SiC type, some ended up with intermittent lead bonds to the die inside the LED package. This defect inside the part didn’t even begin to show up until after about 3 years of production and thousands of Streamliners sold, and affected maybe 10% of the amps, and we replaced them at no charge for over 10 years. In North America, when an amp comes in for service, we still replace them at no charge. Yes, it was unfortunate. There was no way that we could have predicted it. Fortunately most players were more forgiving.

Yes, units manufactured. I mentioned this because these sorts of issues tend to show themselves after many speakers are out in the field used in a variety of applications. Same sort of thing often occurs with fatigue related reliability issues, which is one reason why more comprehensive modeling and aging analysis is done in higher volume commercial products (especially if a long warranty is offered). I thought that some folks here might be interested in the information I provided, if I was wrong then I’m sorry for wasting my time.

Stevie- Wow, your response is not just off the mark but is insulting as well (complete with a Trump reference which is totally uncalled for). Why do you think it’s necessary to act like this towards others? The entire point of my comment was to share information, specifically related to the question of the port being so deep that it comes within 1/2-1 diameter of the back of the cabinet and the aspect ratio of the smaller ports with equivalent area chuffing (as Phil had mentioned). Specifically, what Phil experienced is an example of the aspect ratio non-linearity that I had addressed that can introduce additional factors and calculation errors with regards to tuning suitability. Just because you are unaware of this or don’t agree doesn’t make the information wrong, or me arrogant. When a port comes to between 1/2 and 1x the port diameter, the static pressure of the air mass against the back of the cabinet can come into play, this too is a non-linear term. Non-linear terms result in a cabinet’s tuning changing with level (all cabinet tuning will change to some extent, but the more non-linear the greater the shift with level. This is especially problematic in compact cabinets. Have you ever modeled the non-linear math behind this? Stevie - my comments were general in nature, not specific to your precious design. Perhaps you should re-read my comments with your big boy comprehension.

Respectfully Stevie, I have designed commercially successful bass guitar and pro audio cabinets for over 40 years, including compact LF cabinets. Not just a few dozen or a hundred cabinets but tens of thousands of cabinets. There’s nothing “weird” about my assertion, when the port depth extends to within between 1/2 and 1 times the diameter of the back of the cabinet, additional lossy (and non-linear) terms enter the calculations for the dynamic tuning of the cabinet (ie. the tuning varies with level). With many (not all) 10” drivers suitable for bass guitar, it’s not uncommon to find that in a compact cabinet a 4” port results in a depth that’s too deep for commonly accepted cabinets. When encountering this condition, the options are to either make the cabinet deeper or to reduce the port area to reduce the depth. For example, if the ratio of depth to area is 2:1, a reduction of port are by only 10% affects the depth by (roughly) 20%. This might be enough to mitigate the issues without impacting port velocity significantly. I never suggested decreasing the port diameter to 3”, just to be aware that sometimes, recognizing that there may be an issue, a small adjustment may be helpful. It’s all part of managing the trade offs. That’s all, nothing more.

What you are experiencing with your port depth being so long is because the port area is too large for the driver and displaced volume. As the port becomes more than a few times the diameter of the port, there can be non-linear terms that affect the tuning (one reason why calculated and measured port responses can vary). Also, the resistance (or lossy) term of the port can add a non-linear variable, especially when the end of the port gets close to t he back of the cabinet. The way to prevent this is to calculate the port area and length, then verify that the length is reasonable. If not, you may need to adjust the port area to get length down to a reasonable value... though there are those who will bend the port like a pipe with an elbow (but this too adds non-linearities). In general, a port length of less than 2x the diameter ends up to be a reasonable compromise IME.

For 1/4" speaker applications, use TS (tip-sleeve), do not use TRS cables because of the potential for miswiring of the ring which would short to the sleeve in some types of jacks.

I don't know, I didn't design the amp.

Designer's choice.

Have you looked at the owner’s manual to see how it’s supposed to work?

There, I fixed it for you Paul

Exactly right, colloquialisms across the pond go both ways and I didn't want to leave out either the northeast or the south (easterly), but I probably should have thrown in a "cool man" or "dude" or two for the west coast

What exactly are you having difficulties with?

Why is it that folks who clearly do not understand something feel they are qualified to accuse others of something that they do not even understand? There are SOME manufacturers who use optimistic power metrics when rating their amps, they are almost always manufacturers offering product at the lower levels of performance and budget, resulting in their need to use metrics that have larger numbers for marketing purposes (which works very well when the customer doesn't understand). There are also many manufacturers that do not feel the need to do so, they clearly state the power based on Watts (RMS) and at whatever THD the power is measured at. These manufacturers are generally marketing towards players who understand more about gear, and are looking for performance first, with cost as a secondary concern. Why is there a particular need to be rude here? Have a wicked pissah day y'all.

He was a great songwriter but in his later years both his playing and singing suffered. I worked with him several times as he was winding down his touring, people bought tickets more for the stories he told and his legend status than anything else. He is also a great guy to work with and his personality was an inviting aspect to his show.

No, not all amp manufacturers are more guilty of this. Don’t accuse others of something you don’t yet understand.