L250/ti bus bar settings ?

[SEAWOLF97]

Hi y'all

I'm still playing around with my bus bar settings....when I got the 250ti's the mid bar was down a notch,,then I moved them all down 1 notch....just today moved them again "all to zero" ...

You owners out there ...how are yours set ?

[opimax]

I have the TIBQ Xo that has been charge coupled so I have 2 switches, both set to the least amount of high end

Last night I hooked up the the 2nd set (original L250 w/TI drivers) but haven't turned it on, maybe tonight :) ,they have the bus bars in the original L250 also but it is a different XO

Mark

[jblnut]

All of mine are set at 0db (no attenuation). With my previous SS amp on top, I liked to have them all set at -1db to tame the highs on some bright digital source material. I find that's no longer necessary with tubes.

jblnut

[SEAWOLF97]

Has anyone considered replacing the bus bars ?? They seem prone to surface corrosion...try wrapping heavy gauge wire ?? or copper bars ? or buff up the existing ones ? or ?

[4313B]

Has anyone considered replacing the bus bars ?? They seem prone to surface corrosion...try wrapping heavy gauge wire ?? or copper bars ? or buff up the existing ones ? or ?No, I've never seen any corrosion. You could buy a bunch of the K2-S9800 jumpers instead and try those. :p

[Titanium Dome]

If by corrosion you mean a kind of patina that develops over time, yes.

[varice]

I recently changed my 250Ti bus bar settings. They were all set flat at 0dB except for the ultra high at -1dB. But now I have moved the ultra high to the 0dB setting.

[mike]

The owner's manual states that adjustment of the bus bar attenuators will not alter the character of the speaker significantly. Sometimes I adjust the level of the 044Ti tweeter on mine. I suspect that the real reason they put bus bars on them was to give them something in common with the Hartsfield and early Paragon.

Mike

[SEAWOLF97]

The owner's manual states that adjustment of the bus bar attenuators will not alter the character of the speaker significantly. Sometimes I adjust the level of the 044Ti tweeter on mine. I suspect that the real reason they put bus bars on them was to give them something in common with the Hartsfield and early Paragon.

Mike

I have some problems with that post.

having played with the bars a bit,,have found that the quasi "east coast" or "west coast" experience can be approximated thru bar manipulation.

Also doubt the bars were just made to be " something in common with the Hartsfield and early Paragon." .... my guess is that they knew the scratchy pots problems would occur in the future and since they were marketed to the higher end buyer, ... that they were made to be most foolproof/low maintenance possible.

[4313B]

they were made to be most foolproof/low maintenance possible.A

[varice]

Has anyone considered replacing the bus bars ?? They seem prone to surface corrosion...try wrapping heavy gauge wire ?? or copper bars ? or buff up the existing ones ? or ?

I have noticed that the bars and screws have gotten a little less shiny over time, but I have not really considered replacing them. I will occasionally loosen and tighten the screws a couple of times just to make sure there is some fresh metal between the post threads, the screw heads and the bus bars.

[SEAWOLF97]

I will occasionally loosen and tighten the screws a couple of times just to make sure there is some fresh metal between the post threads, the screw heads and the bus bars.

prolly a good idea ..

I had read this in a catalog

http://www.mapleshaderecords.com/audioproducts/biwirejumpers.php

and have some sheet copper , may try a DIY replacement, tho no problem currently exists.

[SEAWOLF97]

found the copper ....cut up some bus bars ( tho w/o audiopile approved scissors) .....Oh wow , the veil was lifted ...the right speaker that sometimes sounded like a left now sounds like a right all the time, the tunes on XM got better , the draft under the front door..stopped ....got NO BILLS in the mail today ....WOW ...it was a life changing experience. :bouncy: Gotta do the left one soon.

alternative answer....maybe no diff ?

going to sandwich the originals over the copper as they get tweeked when you power tighten the screws ...but the copper is the one will be making contact.

[thymanst]

I have all three l250's straps at 0db - This thread got me to clean the straps and a little more details seems to be shining thru...:)

[SEAWOLF97]

I have all three l250's straps at 0db - This thread got me to clean the straps and a little more details seems to be shining thru...:)

All joking aside ....I did put the original bars back on OVER the top of the copper ON THE RIGHT ONLY .....it SEEMS to be a little brighter and may have gained slightly on the db level ...and does SEEM a little different than the untreated left speaker. MAY have gotten same result from the cleaning that you did.

nothing verifiable, just a subjective opinion , but it cant hurt .....:)

MUCH LATER ....have been listening to WAR on LP and I'll be darned ,,,its like I had turned up the "presence" knob (if there was one) a notch or two ..its an album that I've been listening to often this last 3 weeks...and it does sound "more direct" now.

takes about a half hour, maybe a dollar in sheet copper , yes , I would do it again.

[thymanst]

My bus bars were oxidated a bit and I sanded them lightly - I had the same effect cleaning them - the soundstage seems to have moved forward some and presence is a good word for it (brighter perhaps?) I'm thinking I might try some copper (stripped speaker wire) and see if that changes anything.....:) My bus bars were good at 0db but if it brightens up even more I may have to move the Ultra down a notch.....

[hjames]

Brass, copper, meh - its still going to tarnish and change value and sound ...

Y'all need to get serious and hammer out some Gold or Platinum buss bars and fix this problem for good!

:D Just 'cause I'm smiling doesn't mean I'm kidding :D



My bus bars were oxidated a bit and I sanded them lightly - I had the same effect cleaning them - the soundstage seems to have moved forward some and presence is a good word for it (brighter perhaps?) I'm thinking I might try some copper (stripped speaker wire) and see if that changes anything.....:) My bus bars were good at 0db but if it brightens up even more I may have to move the Ultra down a notch.....

[SEAWOLF97]

Brass, copper, meh - its still going to tarnish and change value and sound ...

Y'all need to get serious and hammer out some Gold or Platinum buss bars and fix this problem for good!

:D Just 'cause I'm smiling doesn't mean I'm kidding :D

I know what you are saying, HJ ,,,but the copper sheets I have are at least 20 years old, they were so shiny that I could not photo them direct on, saw NO tarnish.

Got to thinking about what all my previous posts mean ...presence , direct , etc ...was having a hard time putting words to it.

MIDS ... it is the mids.. hear it in voices mostly. I doubt that the copper gave me more than designed mids , must have rescued mids that were down a bit.

If I were to do it again, wud just cut rectangular strips and make holes with a paper punch and slip them onto the posts and then cover with orig bus bars and screw it all down

[varice]

Since there is a series resistance built into the crossover network for each of the three drivers affected by the bus bar settings, that alone would make it virtually impossible to hear the miniscule difference in resistance between a stock (nickel plated?) bus bar and one made of some other good conductor. As long as you make sure that you have good metal-to-metal contact, the stock bus bars will do just fine.

[mike]

I'm surprised, after reading this thread I put a little effort into getting my bus bars to make better contact and it made the speakers sound a lot brighter and more alive. I guess my mid and high frequency drivers had been attenuated by resistance that developed as a result of the oxidation of the bus bars.

If you own a pair of these it is definitely worth checking the bus bars or even replacing them with something less prone to corrosion.

Mike

[SEAWOLF97]

Since there is a series resistance built into the crossover network for each of the three drivers affected by the bus bar settings, that alone would make it virtually impossible to hear the miniscule difference in resistance between a stock (nickel plated?) bus bar and one made of some other good conductor. As long as you make sure that you have good metal-to-metal contact, the stock bus bars will do just fine.

both Mike & I seem to disagree with that.


I'm surprised, after reading this thread I put a little effort into getting my bus bars to make better contact and it made the speakers sound a lot brighter and more alive. I guess my mid and high frequency drivers had been attenuated by resistance that developed as a result of the oxidation of the bus bars.

If you own a pair of these it is definitely worth checking the bus bars or even replacing them with something less prone to corrosion.

Mike

yes, I could hear the difference, those with "bus bar" systems shud check it out,,,costs no money, just a little time to verify.

[rdgrimes]

Playing with my new L250s. I felt like compared to the rest of my L-family they were a bit weak in the MF and HF, like maybe the mid-bass driver was over-powering the top end a bit. Bars were all set to 0db.

Removed all bars and burnished them with 400 grit sandpaper, then replaced and put the mid-bass bar in the -1.5db position. I feel like it made a positive improvement.

Once I get them moved to my HT room I can use the AVR's PEQ setup routine to get a closer idea of how flat they curve.

On all the 3-way L series, the LE5s really jump out and grab you, on these they are much more subdued. It'll be interesting to see how these L250s EQ.

[SEAWOLF97]

I read a thread here (cant find now) complaining about lack of low bass on 250ti's. The recommendation was to lower all the bars by one stop....I tried that and do PERCEIVE more bass with this setting..... WHY ?

[opimax]

probably one of my threads on lack of bass which has been resolved.

If you reduce the upper end the bottom end will seem larger in relative terms???

Mark

[jbl_daddy]

On a seperate note does a 250ti have the ability to be bi-amped?

[opimax]

L250 & 250ti have single inputs, The TIBQ version and Jubilee (European and Limited Edition) have 2 inputs...as far as i know


Mark

[hjames]

L250 & 250ti have single inputs, The TIBQ version and Jubilee (European and Limited Edition) have 2 inputs...as far as i know


Mark
Well, you kin fix THAT easy enough, right?

[rdgrimes]

I read a thread here (cant find now) complaining about lack of low bass on 250ti's. The recommendation was to lower all the bars by one stop....I tried that and do PERCEIVE more bass with this setting..... WHY ?
I'm having a hard time wrapping my brain around a complaint of inadequate bass in the 250ti. I'd have to suspect an inadequate room, inadequate setup and/or inadequate placement and especially inadequate power.

My L250 are putting out excess bass below 80Hz, and in fact are attenuated as much as 8-10db at 40Hz in my setup to obtain a flat response. That's with a 400W/ch amp in a 400sf room.

[hjames]

I'm having a hard time wrapping my brain around a complaint of inadequate bass in the 250ti. I'd have to suspect an inadequate room, inadequate setup and/or inadequate placement and especially inadequate power.

My L250 are putting out excess bass below 80Hz, and in fact are attenuated as much as 8-10db at 40Hz in my setup to obtain a flat response. That's with a 400W/ch amp in a 400sf room.

Well, we were over there last year and can confirm it seemed like he had lowered BASS in that system -
there was a lot of very good high end gear connected (Adcom and Perraux),
plus he had some custom built CC-crossovers that he wasn't sure were playing well
with his US based drivers (perhaps they were made for one of the Euro models of 250ti?).
Plus his Velodyne SMS and driver, plus the B-460 ...

But it sounds like he's gotten that all resolved.

[SEAWOLF97]

I'm having a hard time wrapping my brain around a complaint of inadequate bass in the 250ti. I'd have to suspect an inadequate room, inadequate setup and/or inadequate placement and especially inadequate power.


My 250ti's (and others that I've read about) are kind of a Jekyll / Hyde speaker ....At least half the time they are just OK ... not really special, but then you'll hit the right tune and *PRESTO* they are "world class" (at least for me).

They can sound rather thin (opposite of lush) and these changes are all on the same system/room . Most that I've seen do run a sub in addition..the 250ti as I recall , is good to about 32hz ....if you want lower bass - add a sub.

All that I can figure is its a characteristic of the network ...I'm not complaining , still dialing them in.....you can really alter their character from West Coast forward to rather reserved Advent sound thru bus bar manipulations.

this is mostly my opinions and your mileage may vary. ;)


I'd have to suspect .... especially inadequate power.


375 solid WPC in 8 ohms 450wpc in 4 ..prolly adequate.

[rdgrimes]

My 250ti's (and others that I've read about) are kind of a Jekyll / Hyde speaker ....At least half the time they are just OK ... not really special, but then you'll hit the right tune and *PRESTO* they are "world class" (at least for me).

They can sound rather thin (opposite of lush) and these changes are all on the same system/room . Most that I've seen do run a sub in addition..the 250ti as I recall , is good to about 32hz ....if you want lower bass - add a sub.

All that I can figure is its a characteristic of the network ...I'm not complaining , still dialing them in.....you can really alter their character from West Coast forward to rather reserved Advent sound thru bus bar manipulations.

this is mostly my opinions and your mileage may vary. ;)



375 solid WPC in 8 ohms 450wpc in 4 ..prolly adequate.

I have noticed a real dependence on adequate room space with my L250. They sound very different in different rooms, much more so than any other large unit I've used. But I would never consider the use of the word "thin" in describing their sound, (except in a small room). The opposite in fact, and if I ever had a criticism for them it would that they produce too much bass. I sometimes feel they are too laid back in the LE5-11s, but repeated evaluation reveals they are not lacking in the response curve. When I tried them in my office with 350W and about 1700 cu ft, they sounded pretty bad, weak and garbled. In my HT room with 400W and 4800 cu ft, they changed completely and are hard to distinguish from my PS1400/PT800 stacks.

As to freq response, nothing under 40Hz is audible and really serves only for LFE. The exception is the pipe organ, which can produce sound under 40Hz when pushed. That said, I've pushed the 250s pretty hard with sweep tones down to 20 Hz and was impressed with the response under 40Hz. Not massive, but certainly not puny either. They peak in the 40-60Hz range. For music, they are near perfect.

[SEAWOLF97]

I When I tried them in my office with 350W and about 1700 cu ft, they sounded pretty bad, weak and garbled. .

Ok...you made me measure ...my listening area is about 1700cuft ....not going to waste them on the larger HT room since I listen to 2 channel more and already have speakers that I like in the HT.

BUT...they do sound great on some source in that room, so I'm discounting the room effect.

[rdgrimes]

Room shape and treatments are as important as size. You should try them in the HT room just for fun, it might change your thinking. ;) In my rooms, the difference was amazing to say the least.

I ran them in the HT room for a while with no EQ, but finally opted for a full flat-response EQ setup. (too much bass ;) )

[opimax]

My lack of bass was 2 issues, out of phase between 14 & 8 and a setting on preamp which was the extreme wrong way for bass that I liked. The CC XO do make them sound different from the non CC set I have, less bassy.or added high end.

My room is not ideal I have been told and believe 2 open doorways, an open stair way, bay window and more I would guess.

As soon as I figure out how to post pictures I can show what I have and what the room is like and some pictures of a confusing xo picture

Anyone in the DC area is welcome to come see and listen

I still have some unanswered questions about phasing but it could be my other equipment or wiring ???

But it is working pretty much and sounds pretty good, in stereo I believe it is correct!

Mark

[SEAWOLF97]

The rear of the 250ti has adjustments for HF and UHF ...but there is only 1 hf driver...are there really 2 adjustments for a single driver ? or is some of the hf covered by the mid ?

[opimax]

I believeit is per speaker, 44, 104 , 108 in the tI series so comparable speakers in standard version

Mark

[SEAWOLF97]

I believeit is per speaker, 44, 104 , 108 in the tI series so comparable speakers in standard version

Mark

that doesnt appear to make much sense...anyone else ?

[SEAWOLF97]

So - those would be the drivers ...

L250 - drivers per Techbot
http://www.audioheritage.org/vbulletin/showthread.php?t=10623

Woofer gets no shunt.
108H = Midrange
104H - High F
044 - UHF transducer

well, not exactly ...from the 250ti PDF

[opimax]

Now what doesn't make sense? lol The first effects the the real tweeter, in the TI it is a 044ti. the 2nd the mid tweeter, 104h the 3rd mid driver the 108h in the TI series.

In the original series I don't know the model # off the top of my head, it is gold...the compares to the 044TI, the mid tweeter is an le5-9 or 11 or some such number which compares to the 104h, the 108h is the same.

So how about this for an explanation, the top 3 speakers are controlled by each different section of the bus bar groups, each speaker (again of the top 3) are controlled by their own set of bus bars.

Ok somebody that doesn't own a set see if it makes sense to them and if they get it....:applaud:

[hjames]

Now what doesn't make sense? lol The first effects the the real tweeter, in the TI it is a 044ti. the 2nd the mid tweeter, 104h the 3rd mid driver the 108h in the TI series.

In the original series I don't know the model # off the top of my head, it is gold...the compares to the 044TI, the mid tweeter is an le5-9 or 11 or some such number which compares to the 104h, the 108h is the same.

So how about this for an explanation, the top 3 speakers are controlled by each different section of the bus bar groups, each speaker (again of the top 3) are controlled by their own set of bus bars.

Ok somebody that doesn't own a set see if it makes sense to them and if they get it....:applaud:

Yep, I don't even OWN a set and its pretty obvious, based on the 250Ti Engineering Standard posted by Techbot here
http://www.audioheritage.org/vbulletin/showthread.php?t=10623
that Greg Timber is calling the 104H a High F transducer. But don't take my word - its right there in black and white ... and that terminology also matches the words on the shunt plate on the back of the speaker

http://audioheritage.org/vbulletin/attachment.php?attachmentid=39676&stc=1&d=1243881701

[SEAWOLF97]

its pretty obvious, based on the 250Ti Engineering Standard posted by Techbot here
http://www.audioheritage.org/vbulletin/showthread.php?t=10623
that Greg Timber is calling the 104H a High F transducer.


all that is understood, and he also calls the UHF a 033ti . He was either having a bad day or there were more changes ....mebbe start a poll ??

WHAT IS A 104H ?

a) tweeter
b) mid
c) both

which nicely cycles back to the question in post 35

>> is some of the hf covered by the mid ?

'cause I vote "b" ..as per the PDF

[hjames]

all that is understood, and he also calls the UHF a 033ti . He was either having a bad day or there were more changes ....mebbe start a poll ??

WHAT IS A 104H ?

a) tweeter
b) mid
c) both

which nicely cycles back to the question in post 35

>> is some of the hf covered by the mid ?

'cause I vote "b" ..as per the PDF


But most crossovers I've played with split the frequencies out to fit the various drivers in the system. So, instead of using an L-pad (which gets dirty and intermittent) to feed a specific driver, your system has buss bars, or "shunts" to choose predetermined values.

http://manuals.harman.com/JBL/HOM/Technical%20Sheet/250Ti%20ts.pdf

Why would it be completely different than most speakers and be built like an equalizer, set for a center frequency between drivers?

More likely to think its built so that each bank of shunts is matched to a specific driver.

So, do you trust the engineer standard from the design engineer,
or the owners manual vetted by the marketing department?

or just make something up?:applaud:

[opimax]

The 104h in this application goes from 1.4 to 5.2 kh,z is that a tweeter or a mid?

Mark

[hjames]

The 104h in this application goes from 1.4 to 5.2 kh,z is that a tweeter or a mid?

Mark



http://manuals.harman.com/JBL/HOM/Technical%20Sheet/250Ti%20ts.pdf



Pretty funny - check the 2 page sheet I've linked to
on the schemo on the first page they show them as LF, MF, HF, UHF (see right edge),
but on the next page in the exploding diagram, from top to bottom they are described as
Hi Freq, Mid freq, Mid range, and Low Freq

Its just a name, not so important ...

[jbl_daddy]

I am trying to find a post on the proper distance from the wall a 250ti should sit??? Have not found much on the search engine. Also does anyone have the link to a more detailed owners book on the ti besides the two page package sheets refrenced earlier in the post? Thanks Mark

PS. My wife had an intresting comment when she got home and looked at the new speakers, she said "well they are not as ugly as the other ones" I take that as she likes them... :)

[mike]

I believe it is three feet. I think the JBL website has an owner's manual specifically for the 250Ti on it. They are one of those speakers that benefit from experimentation with placement and electronics.

Mike

[4313B]

PS. My wife had an intresting comment when she got home and looked at the new speakers, she said "well they are not as ugly as the other ones" I take that as she likes them... :)Such a common theme. They really seem to go for built-in and camouflaged.

I'm working on a new loudspeaker design that morphs into various plant species as desired.

[Fred Sanford]

I'm working on a new loudspeaker design that morphs into various plant species as desired.

Don't do it. In my experience, they'll always over-water it and leave rings on whatever's underneath it.

:yes:

je