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alnitak
01-03-2011, 11:02 AM
I'm new to this forum, and I suspect this question has been asked before. However, I tried the search function and looked through a bunch of pages of threads and couldn't find an answer.

Back in 1975 I purchased a pair of L100s...loved the sound! Later, when a flood in my house ruined my other equipment (MacIntosh tube amp, Nak 700, etc.) I upgraded my system and bought a pair of CT-2000's to match. So, the speakers haven't gotten much use.

For Christmas, my wife bought me a 55" Sony Bravia LED-LCD 1080p TV. I have a modest Pioneer 5.1 A/V receiver and was considering using the L100s as the front speakers (I would use the CT-2000's, but they are 4 ohm and the receiver is rated for 6-16 ohm).

Is there any issue with using the L100s as part of a home theater system, e.g., lack of video shielding, ability to handle rapidly changing and loud DVD effects, etc.? Will I end up damaging the TV or the speakers? Will I lose fidelity or the ability to keep up with the DVD because of older materials (e.g., vs. titanium tweeters, etc.)? Can I get by with these temporarily until I save the cash for a new set of speakers?

Thanks for your advice.

Titanium Dome
01-03-2011, 11:57 AM
Welcome, Al, and Happy New Year!

Assuming the L100s are in good condition, they should fill in just fine. Since my original pair bought in 1970 still functions flawlessly today, I think you'll be just fine as long as you don't overdrive them; that is, put too much power into them and drive them to distortion.

The L100s will do okay as HT speakers if you're aware of their limitations.

1. They cannot deliver the LFE (low frequency effects) information intended for powerful subwoofers. They weren't built for that. You need a sub or subs to handle it.

2. They are not shielded, so putting them too close to the set could affect the picture. However, since you don't have a CRT, this isn't quite as big a deal. You'll be able to determine how close or far away they need to be with a little trial and error placement.

3. The HF info won't be as precise or clean as with a more modern speaker, but it will be there. Again, avoid turning up the volume to stupid levels and the tweeters will handle the HF just fine.

4. Their frequency response is biased toward the midrange, so you should get plenty of output there, and dialog should be good. However, the question of what you'll use as a center channel becomes important, since it may have a much different tonal balance and timbre than the L100. This can create a muddled or indistinct midrange if the difference is noticeable. Or are you planning on no center or phantom center? That might work better until you get a complete set of HT speakers.

5. "Speed" is not an issue. Sound travels at the same speed regardless of the speaker driving it. Anyway, there should be an adjustment in your audio-video receiver or TV set to adjust the timing if dialog and lip sync are off a tiny bit, as they sometimes are due to issues other than what kind of speaker is being used.

In any event, the L100s will be head and shoulders above any speaker built into the TV, and they will make the experience much better for you than simply using built in speakers. I know of at least one guy who has a whole HT based on five L100s and a pair of subs. It sounds very good, and he's happy and proud.

Good luck.


I'm new to this forum, and I suspect this question has been asked before. However, I tried the search function and looked through a bunch of pages of threads and couldn't find an answer.

Back in 1975 I purchased a pair of L100s...loved the sound! Later, when a flood in my house ruined my other equipment (MacIntosh tube amp, Nak 700, etc.) I upgraded my system and bought a pair of CT-2000's to match. So, the speakers haven't gotten much use.

For Christmas, my wife bought me a 55" Sony Bravia LED-LCD 1080p TV. I have a modest Pioneer 5.1 A/V receiver and was considering using the L100s as the front speakers (I would use the CT-2000's, but they are 4 ohm and the receiver is rated for 6-16 ohm).

Is there any issue with using the L100s as part of a home theater system, e.g., lack of video shielding, ability to handle rapidly changing and loud DVD effects, etc.? Will I end up damaging the TV or the speakers? Will I lose fidelity or the ability to keep up with the DVD because of older materials (e.g., vs. titanium tweeters, etc.)? Can I get by with these temporarily until I save the cash for a new set of speakers?

Thanks for your advice.

Rolf
01-03-2011, 01:17 PM
No TI. That is not correct. The L100 uses Alnico magnets, and they are shielded. No influence on a "TV", and anyway not on a LCD flat screen.


Welcome, Al, and Happy New Year!


2. They are not shielded, so putting them too close to the set could affect the picture. However, since you don't have a CRT, this isn't quite as big a deal. You'll be able to determine how close or far away they need to be with a little trial and error placement.

Good luck.

alnitak
01-03-2011, 01:54 PM
1. They cannot deliver the LFE (low frequency effects) information intended for powerful subwoofers. They weren't built for that. You need a sub or subs to handle it.

Got one, a 12" Cambridge Soundworks Powered Subwoofer with the bypass set at 80 Hz.


2. They are not shielded, so putting them too close to the set could affect the picture. However, since you don't have a CRT, this isn't quite as big a deal. You'll be able to determine how close or far away they need to be with a little trial and error placement.

They are about 6"-8" to the side of the LCD. I don't see any impact on the color or picture. From what I've read, the LCD screens are not susceptible to magnetic interference. Correct?


3. The HF info won't be as precise or clean as with a more modern speaker, but it will be there. Again, avoid turning up the volume to stupid levels and the tweeters will handle the HF just fine.

Thanks. That confirms what I suspected. While good for music, the L100's aren't as "crisp" as more modern speakers in their HF response..


4. Their frequency response is biased toward the midrange, so you should get plenty of output there, and dialog should be good. However, the question of what you'll use as a center channel becomes important, since it may have a much different tonal balance and timbre than the L100. This can create a muddled or indistinct midrange if the difference is noticeable. Or are you planning on no center or phantom center? That might work better until you get a complete set of HT speakers.

I have a Klipsch center speaker (Model SC1 I think), rated at 8 ohms and 100 watts. Seems to work OK.


5. "Speed" is not an issue. Sound travels at the same speed regardless of the speaker driving it. Anyway, there should be an adjustment in your audio-video receiver or TV set to adjust the timing if dialog and lip sync are off a tiny bit, as they sometimes are due to issues other than what kind of speaker is being used.

No issues there. I was just worried that the responsiveness of 30 year-old materials (dome, etc.) wouldn't be well matched for today's digital transmission, and may sound "muddy" or get stressed by the (sometimes) loud and dynamic sound effects on DVDs.

Thanks for the response, TiDome! It helps a lot.

alnitak
01-03-2011, 01:57 PM
No TI. That is not correct. The L100 uses Alnico magnets, and they are shielded. No influence on a "TV", and anyway not on a LCD flat screen.
Thanks Rolf. Good to know.

I used them for a few years next to a Mitsubishi 55" large screen and was wondering why I didn't see any issues. Good to know that JBL was years ahead in their design.

Eaulive
01-03-2011, 02:50 PM
Watch my avatar, I have 4 L100 and a box made with a 2213H and some other components to try and mimic the sound of the L100 (unsuccessfully) for center channel.

I drive them with a first generation Pioneer VSX D606 dolby digital 5 x 100W, I have a subwoofer but I drive them full range anyways, and I'm not a quiet person :D

No problem what so ever since the last 14 years... and I love them! :applaud:

Eaulive
01-03-2011, 02:52 PM
No TI. That is not correct. The L100 uses Alnico magnets, and they are shielded. No influence on a "TV", and anyway not on a LCD flat screen.

The woofer and midrange are alnico, the tweeter is ferrite.

Rolf
01-03-2011, 03:01 PM
I know. But the little interference from those are of no concern. Anyway with the modern LCD screens ..No problem, and I can't believe it was a problem on older TV's as well. Not so here at my place anyway.


The woofer and midrange are alnico, the tweeter is ferrite.

alnitak
01-03-2011, 03:02 PM
I drive them with a first generation Pioneer VSX D606 dolby digital 5 x 100W, I have a subwoofer but I drive them full range anyways, and I'm not a quiet person :D

No problem what so ever since the last 14 years... and I love them! :applaud:
How funny...my wife got me a Pioneer VSX D608 years ago, and that's what I've been using.

Where do you set the crossover for LFE? I think 100, 150 and 200 are the only options for the Pioneer, so I chose 100 Hz. My subwoofer has settings for 55, 80, 100 and 140. Should I use 100 for that as well (it's currently set on 80)? If I set to 100, does that rob the speakers of some low end?

Rolf
01-03-2011, 03:09 PM
The L100 does not play low frq. They stop at about 70Hz, (-4db) so I believe the 100Hz will be the best. Those who know more than me may climb in.


How funny...my wife got me a Pioneer VSX D608 years ago, and that's what I've been using.

Where do you set the crossover for LFE? I think 100, 150 and 200 are the only options for the Pioneer, so I chose 100 Hz. My subwoofer has settings for 55, 80, 100 and 140. Should I use 100 for that as well (it's currently set on 80)? If I set to 100, does that rob the speakers of some low end?

Eaulive
01-03-2011, 06:45 PM
I know. But the little interference from those are of no concern. Anyway with the modern LCD screens ..No problem, and I can't believe it was a problem on older TV's as well. Not so here at my place anyway.

Nope, never had a problem here either.

Eaulive
01-03-2011, 06:54 PM
How funny...my wife got me a Pioneer VSX D608 years ago, and that's what I've been using.

Where do you set the crossover for LFE? I think 100, 150 and 200 are the only options for the Pioneer, so I chose 100 Hz. My subwoofer has settings for 55, 80, 100 and 140. Should I use 100 for that as well (it's currently set on 80)? If I set to 100, does that rob the speakers of some low end?

The way my receiver works is very basic, you choose if your speakers are "small" or "large" for each channel. If you set it to "large", then it's full range, no LF cutoff. If you set it to "small", everything that is lower than 120Hz goes to the LFE channel. Remember it's a 1996 model :D

I have them all at "large", so full range. And I checked it, it's really full range.
The LFE channel kicks in at 120Hz, I just had to be careful with the phase of the subwoofer so I don't have problems between 60-120Hz.
That's the setup I have, on the receiver I have the HF control flat, and the LF at -5dB I guess, (9 o'clock), but usually the "loudness" is on.

Controls on the L100s are flat also.

Titanium Dome
01-03-2011, 08:52 PM
No TI. That is not correct. The L100 uses Alnico magnets, and they are shielded. No influence on a "TV", and anyway not on a LCD flat screen.


The woofer and midrange are alnico, the tweeter is ferrite.


I know. But the little interference from those are of no concern. Anyway with the modern LCD screens ..No problem, and I can't believe it was a problem on older TV's as well. Not so here at my place anyway.

Well, since we're into throwing around corrections, the AlNiCo magnet is not shielded. Period.

What makes it less intrusive is that its magnetic flux is much tighter and tends to stay focused in the magnet and tight magnetic gap, and produces negligible leakage flux patterns compared to ferrite and ceramic magnets. Neodymium has similar characteristics, and it is sometimes referred to as "naturally shielded," but this is technically incorrect, too. A shielded speaker has a containment, usually of mu metal, that captures magnetic flux leakage, creates its own magnetic field, and creates a shield around the magnet to imprison the flux leakage.

Neither AlNiCo nor Nd need to be shielded in most applications because of low flux leakage.

Eualive is correct that the L100 tweeter is ferrite, and Rolf is correct that it is small, but it easily interfered with many black and white TVs of the day. As TVs improved, they were able to reject more and more flux leakage, though CRTs were always susceptible to a certain extent.

It is mostly correct that LED/LCD TVs are not affected by magnetic flux, but they're not impervious. Just because someone's never seen something does not mean it never happens. In my own owner's manuals it says as much, and several I looked at on line warned about it as well. That's why my recommendation of trial and error placement was made. You can get them as close as you can get them.

Again, you should be fine. Enjoy your new TV. :)

Robh3606
01-04-2011, 08:15 AM
Well, since we're into throwing around corrections, the AlNiCo magnet is not shielded. Period.

Hello T Dome


What determines if it is shielded or not is not the magnet type but the design of entire magnetic circuit. Closed pot magnetic structures like a JBL Alnico's are inherently "shielded" because there is little flux leakage as compared to an open structure like your typical ferrites. They can be put much closer to a CRT because of the low flux leakage.



A shielded speaker has a containment, usually of mu metal, that captures magnetic flux leakage, creates its own magnetic field, and creates a shield around the magnet to imprison the flux leakage.


Most use a simple bucking magnet which is just as effective and cheaper than MU metal which is very expensive stuff. Mu metal shunts the magnetic Field, it doesn't create an opposing one. Only a bucking magnet can do that.

Rob:)

Eaulive
01-04-2011, 09:27 AM
Most use a simple bucking magnet which is just as effective and cheaper than MU metal which is very expensive stuff. Mu metal shunts the magnetic feild, it doesn't create an opposing one. Only a bucking magnet can do that.

Rob:)

Like what I did on my 2213 that I use as center channel :D
4919849199

Rolf
01-04-2011, 10:41 AM
OK, OK, I bow to the ones more learned than I.


Well, since we're into throwing around corrections, the AlNiCo magnet is not shielded. Period.

What makes it less intrusive is that its magnetic flux is much tighter and tends to stay focused in the magnet and tight magnetic gap, and produces negligible leakage flux patterns compared to ferrite and ceramic magnets. Neodymium has similar characteristics, and it is sometimes referred to as "naturally shielded," but this is technically incorrect, too. A shielded speaker has a containment, usually of mu metal, that captures magnetic flux leakage, creates its own magnetic field, and creates a shield around the magnet to imprison the flux leakage.

Neither AlNiCo nor Nd need to be shielded in most applications because of low flux leakage.

Eualive is correct that the L100 tweeter is ferrite, and Rolf is correct that it is small, but it easily interfered with many black and white TVs of the day. As TVs improved, they were able to reject more and more flux leakage, though CRTs were always susceptible to a certain extent.

It is mostly correct that LED/LCD TVs are not affected by magnetic flux, but they're not impervious. Just because someone's never seen something does not mean it never happens. In my own owner's manuals it says as much, and several I looked at on line warned about it as well. That's why my recommendation of trial and error placement was made. You can get them as close as you can get them.

Again, you should be fine. Enjoy your new TV. :)

Titanium Dome
01-04-2011, 01:55 PM
Hello T Dome

Closed pot magnetic structures like a JBL Alnico's are inherently "shielded" because there is little flux leakage as compared to an open structure like your typical ferrites. They can be put much closer to a CRT because of the low flux leakage.

Isn't that what I wrote, except for not writing "shielded" in quotes to try to sneak the term back in? :D





Most use a simple bucking magnet which is just as effective and cheaper than MU metal which is very expensive stuff. Mu metal shunts the magnetic Field, it doesn't create an opposing one. Only a bucking magnet can do that.

Rob:)

I guess I'm not buying cheap enough speakers, although I do have some prehistoric speakers with bucking magnets.

I'll let this old "Let's Talk Speakers" chestnut by Ted Weber address your mu metal comment.


The wasted, or unusable flux is called leakage flux. Ceramic magnet speakers and modern speakers with large gaps tend to have more leakage flux than vintage AlNiCo magnet speakers with tight gaps. An example of a typical ceramic magnetic circuit and the location of the leakage flux is shown in Fig. 1 below. Shielding the near environment of a speaker from the leakage flux is often important, especially near a television since the picture tube in a TV uses magnetism to direct the electron beam to draw the picture on the screen. The constant leakage flux from the speaker would affect the scanning beam and distort the picture as well as the colors, etc. The best shielding is a canister or pot-shaped cover made of a high permeability metal called mu metal. It is basically a short circuit to the leakage flux so the flux can't get through the mu metal and radiate into the surrounding air. What happens is that the leakage flux tries to magnetize the mu metal, the mu metal generates a magnetic field of its own that resists the leakage flux. All of the magnetism stays within the mu metal so it isn't radiated.

I say potato, you say potahto. Now, let's call the whole thing off.

jcrobso
01-04-2011, 02:53 PM
Hello T Dome


What determines if it is shielded or not is not the magnet type but the design of entire magnetic circuit. Closed pot magnetic structures like a JBL Alnico's are inherently "shielded" because there is little flux leakage as compared to an open structure like your typical ferrites. They can be put much closer to a CRT because of the low flux leakage.




Most use a simple bucking magnet which is just as effective and cheaper than MU metal which is very expensive stuff. Mu metal shunts the magnetic Field, it doesn't create an opposing one. Only a bucking magnet can do that.

Rob:)

Remember that a CRT uses magnetic deflection and that is why they are very sensitive to external flux fields.:(
LCD/Plasma do NOT use any deflection at all, and in general are not subject to stray magnetic fields.
As at test I just subjected my LCD PC monitor to a very strong magnetic field and did NOT see ANY change in the image on the screen.;);)

Also keep in mind that magnetic fields are subject to the same inverse square law that sound waves are subject to. If you do see any image change you may only to move the speaker a few inches away.:)

Robh3606
01-04-2011, 04:15 PM
Hello T Dome



Isn't that what I wrote, except for not writing "shielded" in quotes to try to sneak the term back in? :D


No not at all based on this quote.


Neither AlNiCo nor Nd need to be shielded in most applications because of low flux leakage.

The entire magnetic circuit is what determines what if any stray magnetic leakage there is.


I'll let this old "Let's Talk Speakers" chestnut by Ted Weber address your mu metal comment.

Well that's nice but that's not how it works. Try doing another Internet search here are the results from mine



Will a magnetic shield block the field's effects?

There is no known material that blocks magnetic fields without itself being attracted to the magnetic force. Magnetic fields can only be redirected, not created or removed. To do this, high-permeability shielding alloys are used. The magnetic field lines are strongly attracted into the shielding material. There are many types of shielding materials, Their alloy composition is a highly guarded secret, based on years of extensive research and application. CO-NETIC-AA, NETIC S3-6 and MuMetal are three unique shielding materials provided by Magnetic Shield Corp.


and


Magnetic shielding
The high permeability of mu-metal provides a low reluctance (http://en.wikipedia.org/wiki/Reluctance) path for magnetic flux (http://en.wikipedia.org/wiki/Magnetic_flux), leading to its major use, in magnetic shields (http://en.wikipedia.org/wiki/Magnetic_shielding) against static or slowly varying magnetic fields. Magnetic shielding made with high permeability alloys like mu-metal works not by blocking magnetic fields but by shunting them—providing a path for the magnetic field lines (http://en.wikipedia.org/wiki/Magnetic_field_line) around the shielded area. So the best shape for shields is a closed container surrounding the shielded space. The effectiveness of mu-metal shielding decreases with the alloy's permeability, which drops off at both low field strengths and, due to saturation (http://en.wikipedia.org/wiki/Magnetic_saturation), at high field strengths. So mu-metal shields are often made of several enclosures one inside the other, each of which successively reduces the field inside it. RF (http://en.wikipedia.org/wiki/Radio_frequency) magnetic fields above about 100 kHz (http://en.wikipedia.org/wiki/Kilohertz) can be shielded by Faraday shields (http://en.wikipedia.org/wiki/Faraday_cage), ordinary conductive metal sheets or screens which are used to shield against electric fields (http://en.wikipedia.org/wiki/Electric_field).[2] (http://en.wikipedia.org/wiki/Mu-metal#cite_note-1)



If you have any pictures of shielded JBL's drivers that use Mu Metal please post them.

Rob:)

Titanium Dome
01-04-2011, 06:21 PM
I say potato, you say potahto. Now, let's call the whole thing off.

You get the last word. Really, you win. :applaud: Well done. :)


"I could be arguing in my spare time"

gsxronax
01-20-2011, 10:57 PM
Pardon if this has already been covered but I am looking for a better matching center for my surround system. Any advice, good or bad, is welcome. My system currently consists of:


Processor: Yamaha RX-N600 (6.1 surround processor)
Front speakers: L100S (I bought them new from the Rhein-Main AV Club, in Germany in 1992).
Rear speakers: LXE330 (Bought off craigslist a couple months ago.)
(Bought off craigslist a couple days ago.)
Rear center: nothing at this time


The L100S's are not L100s or L100's. The badging on the front is "L100S", and they are not listed on the JBL website. Nor does it seem that anybody discusses them in forums or anywhere else. I can post a pic if needed.

The LXE330's are a great match for the L100S's as they have the same construction, same tweeters and midbass cones. They also are a great tonal match. They were made between 1994-1995.

The ARC Center is not a great match. It has a very nasal tone compared to the other speakers and the highs are not nearly as crisp. I have cranked it up a bit to compensate but it just isn't cutting it. I just bought it and am not happy with it. http://www.avsforum.com/avs-vb/images/smilies/mad.gif

I have thought of just finding another set of LXE330's for the front and rear centers but am not sure if this is the best way to go as they are not on the smaller size.

grumpy
01-21-2011, 06:25 AM
IIRC, the L100S is a variation of the L100T.

Titanium Dome
01-21-2011, 11:13 AM
IIRC, the L100S is a variation of the L100T.

Yes. The main difference is the vinyl finish on the cabinet. They were intended for PX and commissary sales at military installations.

AMACNEE
01-26-2011, 06:41 PM
Looking at using my L112's for front and L15's for surround in a HT. Wondering if everone's thoughts are the same on the low & high frequency response. Also, struggling with what to do about the center channel. Any experience that can be shared would be appreciated:)