What is even the point of passive crossovers in 2021?

[antcollinet]

Probably a typo where he meant 1 amp/driver.

Yes, that.

 

[mhardy6647]

Classic speakers overwhelmingly came with passive crossovers, but I've never seen any data on longevity of things like the drivers. I'm inclined to believe that speaker manufacturers didn't really give a lot of thought to time-to-failure, and were more concerned with just making good quality speakers for their price range. I certainly know this was the case when I worked at Altec Lansing, and I know that well taken care of examples lasted a long time (mine are still performing as good as they ever did). I've had more troubles with foam surrounds on JBL woofers, but that is easily cured. I've never had a passive crossover fail.

I've got a single Altec 603B here that's probably 70 years old.
My 604Bs are from the early 1950s, so they're pushin' 70 as well.

 

[MakeMineVinyl]

I've got a single Altec 603B here that's probably 70 years old.
My 604Bs are from the early 1950s, so they're pushin' 70 as well.

That's been my experience as well. Shortly before I left Altec (when they were in Anaheim), I scored a bottle of the clear 'goop' that they used to dope the cloth surrounds of their woofers like the 416 because I thought that this was going to be a wear item which would need refreshing at some distant point in the future. As it turns out, I've never had to open that bottle of goop.

 

[pseudoid]

Sorry - meant 1 amp per drive unit. (See, another interchangable term pair - speaker/drive unit)

Makes no sense to me and it could be some 'ad hoc' rule-of-thumb...
So for any given "active" speaker, the designer would be a fool to use anything but an efficient pwm or high voltage DC input wall-warts, or high-Z speakers, etc.

 

[antcollinet]

Makes no sense to me and it could be some 'ad hoc' rule-of-thumb...
So for any given "active" speaker, the designer would be a fool to use anything but an efficient pwm or high voltage DC input wall-warts, or high-Z speakers, etc.

I can't help thinking we're at cross purposes. This is what (and all) I'm talking about...

Powered speakers - Wikipedia

en.wikipedia.org

 

[mhardy6647]

That's been my experience as well. Shortly before I left Altec (when they were in Anaheim), I scored a bottle of the clear 'goop' that they used to dope the cloth surrounds of their woofers like the 416 because I thought that this was going to be a wear item which would need refreshing at some distant point in the future. As it turns out, I've never had to open that bottle of goop.

That's 'cause they over-gooped -- at least judging by the runny goop that one sees more than occasionally on Altec driver surrounds of a certain age.

PS Do NOT get your Altec goop mixed up with Gwyneth Paltrow's goop.

 

[mhardy6647]

(ever so slightly) Less off-topic The JBL "Lansalloy" surrounds, at this late date, seem to cause/be much more trouble than anything I've encountered from Altec.

 

[pseudoid]

Gwyneth Paltrow's goop

I don't understand that type of goop, but will raise you over 200 flavors of Silicone in combined catalogs of GE+DOW alone.
RTV - Silicone potting/encapsulation compounds' are a whole different class in themselves and that half-tube of HomeDepot variety in your garage probably should not be used near PCBs. Digging further deeper, one can find thermally conductive or non-conductive and/or dielectric varieties, but avoid the acidic flavors as if they were the Covid virus for a PCB.
Now, where did I put that tube GE SiliconeII...

 

[MakeMineVinyl]

That's 'cause they over-gooped -- at least judging by the runny goop that one sees more than occasionally on Altec driver surrounds of a certain age.

PS Do NOT get your Altec goop mixed up with Gwyneth Paltrow's goop.

I've found that the goop does indeed run (The Altec goop, not Gwyneth's) and I have to rotate the woofers 180 degrees once a year or so it doesn't run down to the cone.

 

[MakeMineVinyl]

(ever so slightly) Less off-topic The JBL "Lansalloy" surrounds, at this late date, seem to cause/be much more trouble than anything I've encountered from Altec.

View attachment 162488

Looks like that dome took a bullet hit.

 

[MakeMineVinyl]

Here's my bottle of Most Excellent Official Altec Lansing VIntage Speaker Surround Goop. Appears to still be 'goopy' after all these years. Probably goopier than me at this juncture.

 

[Madjalapeno]

Here's my bottle of Most Excellent Official Altec Lansing VIntage Speaker Surround Goop. Appears to still be 'goopy' after all these years. Probably goopier than me at this juncture.

View attachment 162492

Are you a long distance truck driver?

 

[MakeMineVinyl]

Are you a long distance truck driver?

Nope, but come to think of it I wasn't the one who filled the bottle of "speaker goop" - someone filled it for me. Now I'm all paranoid about opening it to check. Its very thick - is that what urine does after 40 years? Ugh, this is getting disgusting.

 

[pseudoid]

Nope, but come to think of it I wasn't the one who filled the bottle of "speaker goop" - someone filled it for me. Now I'm all paranoid about opening it to check. Its very thick - is that what urine does after 40 years? Ugh, this is getting disgusting.

try crowd-sourcing some funds for a brand new bottle... even if you aim to retain the melted snow!

 

[EJ3]

quote:
I design passive xo speakers, self powered speakers and speakers with one or more separate rack mount amplifiers.

A misconception about passive crossovers is that they are inefficient / lossy.

They can be if there is a lot of current passing through resistors but the reactive parts normally have small losses.

Best
Tom

Yes!
When designed correctly, there are not great losses.
I won't say that it is a rumor but major power suck up is not the norm in high quality passive crossovers.
One of my sets of 2-way speakers (which have never been tested in a way that we would be considered adequate) 'sound' pretty good (yes, subjectively [and better with a true subwoofer Xed at 80 Hz]), they have no crossover & the pair can play smoothly & loudly in a small room with 23 watts a channel. Perhaps not having a crossover helps them do the loudly part. I know, no proof of anything (& I would like to one day test them but shipping from SC to Seattle is pricy). So it is not a priority at the moment.

 

[mhardy6647]

(ever so slightly) Less off-topic The JBL "Lansalloy" surrounds, at this late date, seem to cause/be much more trouble than anything I've encountered from Altec.

View attachment 162488

Hey... I mean... I found a pair of LE-8s (or maybe LE-8As) at the dump. That is the worse-looking of the two, as found.
I thought they looked pretty good, but the surrounds were hard as rocks. I have replacement surrounds for 'em, but have never worked up the gumption to do anything with them.

Besides, I also found a pair of these the same day.

JBL N600 by Mark Hardy, on Flickr

and these.

Part of a DIY Metregon kit, perhaps -- but no woofers

PS Hey, I even managed to get back on topic with that N-600 XO!

 

[EJ3]

That's why good active designs have limiters and thermal cutouts for driver protection.

The 'operative word' here being the subjective 'good'?

 

[EJ3]

mostly bought by folks who like music but often arent as discerning as we up in here.

So far I haven't heard a SONOS or Bluetooth speaker that I would bring home to listen to. Not saying that I won't but...

 

[EJ3]

It can be done manually in "BB code" mode by using "LIST=1":

[LIST=1]
[*]foo
[*]bar
[/LIST]

1. foo
2. bar

I presume that you meant the acronym: FUBAR (FU BAR)? (the acronym SNAFU [SNA FU]) might also be fitting.

 

[EJ3]

Sorry - meant 1 amp per drive unit. (See, another interchangable term pair - speaker/drive unit)

I understood it as you state here. Perhaps because I have a wife who has a third-eighth grade level of English & have to interpolate a lot of things.