LE14A Full Range?

[bedrock602]

I have a pair of S99's with LE14A and LE20-1. The woofers have new surrounds but otherwise all is original. The midrange is very "shouty" and unpleasant. Looking at the specifications and schematic of the crossover, the tweeters are crossed over at 2000 hz but it appears that the woofers run full range.

I'm a complete novice but doing a little reading about crossovers, it seems that upper end of the woofer can be controlled with an inductor. I think this would be a nice little experiment that can easily be reversed. If this is reasonable, can someone recommend a value, or range of values for an inductor to limit the woofer to 2000 hz or so? The tweeters and woofers are 8 ohms.

[RMC]

Hi Bedrock,

Ideally you would need a LE14A impedance curve, as well as a response curve, in order to determine a proper "crossover point" with the driver, in your case a low-pass "cutoff point". The reason for this is that driver impedance usually varies with frequency, and the 8 ohm value given is only a nominal number, not an exact across the spectrum number. More often than not, impedance value goes up as frequency goes up.

For illustration purpose only, look at the attached 2226H spec sheet impedance graph, pretty typical with stock form woofers, hence the importance of knowing driver impedance value at a certain frequency.

In the absence of actual LE14A data you're more or less having to go with trial/error method with different inductor values... A simple inductor will give you a 6 db/oct roll-off.

Just to help you get going with the experimentation, the crossover calculator in Winspeakerz gives me, for woofer 8 ohms and frequency of 2 khz, inductor value of 0.6366 MH. Double checking this number in crossover tables I have, I get 0.64 MH, so pretty much the same. Good luck, Regards,

Richard


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[bedrock602]

Thanks Richard, that should be easy enough to find.

Looking at the impedance curve for the 2226H you linked, I see that the impedance at 2000 hz is about 20 ohms.

If one were to use the 0.64 MH inductor you suggested on the 2226H instead, would the crossover point be at 600 hz or so?

[bedrock602]

I found this thread where Zilch tested several LE14A's. The graphs suggest that at 2000 hz, impedance is about 20 ohms.

Am I reading this correctly?

http://www.audioheritage.org/vbulletin/showthread.php?5777-Woofer-Tester-2-LE14A-Fs&highlight=woofer+tester

[speakerdave]

I'm wondering why the described sound problem is attributed to the woofer and not the tweeter.

[bedrock602]

I'm wondering why the described sound problem is attributed to the woofer and not the tweeter.

I also have a pair of L66 and L88, both of which use the same tweeter and are also 2-way designs. I believe those woofers run full range as well, but I'm not certain of it. Anyway, I don't hear any annoying midrange in either of those two speakers so I'm assuming the LE14A is the culprit.

I'm not ruling out the tweeters or the crossovers as a problem though. Open to suggestions.

[RMC]

Hi Bedrock,

For my part I had assumed you already determined the woofer appears to be the bugger. JBL having put a 14"! driver with a tweeter I figured the woofer must go relatively high to avoid a "hole" in frequency response, though possibly pretty directional at some point, but that's another matter.

Yes, in Zilch posts # 1 and 12 impedance is just a little shy of 20 ohms.

As for your question in post # 3, unfortunately the answer is no.

A 0.64 MH inductor at 20 ohms won't give you a 6 db roll-off from 600 hz but rather more around 4 khz. To get a 6 db roll-off starting 600 hz with 20 ohms you need instead an inductor with 5.3 MH (Winspeakerz).

Inductors can also be combined in series or parallel to modify their total value. Regards,

Richard

P.S. In order to help you minimize the guessing work related to choice of inductor value for your low-pass roll-off filter investigation (listening tests), I have a simple chart of high and low-pass filter component values that will probably make your task much easier. If interested, send me a private message here along with an e-mail address.

[bedrock602]

So if the woofers measure 20 ohms at 2000 hz, is this the value that should be used to select components for a 2000 hz crossover?

I found an online crossover calculator and first using 8 ohms, it gave me the same inductor value of .64 MH that Richard posted earlier. I then plugged in 20 ohms for the woofer and was given a value of 1.59 for the inductor.

[RMC]

Hi bedrock,

Great, now you've found a calculator to help you.

The answer to your question in post # 8 is yes.

The 600 hz low-pass filter requiring a 5.3 MH inductor was in relation to your 600 hz question in post # 3.

With regards now to a 2 khz low-pass filter (6db/oct) I get the same result as you: 1.592 MH for the inductor.

Regards,

Richard

[bedrock602]

That's awesome, thank you.

[speakerdave]

I also have a pair of L66 and L88, both of which use the same tweeter and are also 2-way designs. I believe those woofers run full range as well, but I'm not certain of it. Anyway, I don't hear any annoying midrange in either of those two speakers so I'm assuming the LE14A is the culprit.

I'm not ruling out the tweeters or the crossovers as a problem though. Open to suggestions.


The L66 crosses over at 3000, maybe closer to the LE20-1 comfort zone, but if you have the L88 without the upgrade kit, you may have a point there.

It might be interesting to put a new, better, capacitor maybe even a charge-coupled pair, in front of the tweeter as a first step (just to be scientific), and you probably should upgrade there anyway while you have everything apart.

[bedrock602]

The L66 crosses over at 3000, maybe closer to the LE20-1 comfort zone, but if you have the L88 without the upgrade kit, you may have a point there.

It might be interesting to put a new, better, capacitor maybe even a charge-coupled pair, in front of the tweeter as a first step (just to be scientific), and you probably should upgrade there anyway while you have everything apart.

I like the scientific approach although I don't know what a "charge-coupled pair" is.

I pulled the crossover out and found that it is the LX4-1, not the LX8 I assumed it to be from looking thru the library here. Need to dig a little further to find a schematic.

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[Odd]

Lx 4-1
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[bedrock602]

Thank you !

[bedrock602]

I never use the attenuator on any of the speakers that have LE20's so wondering if I can eliminate the switch, two resistors and the 3.0 MH inductor?

At this point, I would leave the original x-overs alone and build new ones from scratch. The boards are just 1/4" masonite with some t-nuts attached. No biggie.

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=84252&d=1558412703

[speakerdave]

I'm wondering why the described sound problem is attributed to the woofer and not the tweeter.



I never use the attenuator on any of the speakers that have LE20's . . . .

I'm still wondering.

[Mr. Widget]

I'm still wondering.I was wondering the same thing. I mean, it could be due to the woofer, but I would look at the tweeter first.


Widget

[bedrock602]

I was wondering the same thing. I mean, it could be due to the woofer, but I would look at the tweeter first.

Widget

How would you suggest looking at the tweeter?

[bedrock602]

I'm still wondering.

What was it about my statement regarding the attenuator that makes you wonder?

[Mr. Widget]

How would you suggest looking at the tweeter?I would run a FR curve of the system without the tweeter and then again without the woofer and see how each performs independently. Then based on that info, if I like what I see with each of them, and there is still a problem then I would try a network redesign because it is likely your problem.

Alternatively if the woofer or the tweeter is giving me the nasty peak, I might see if a network redesign can fix it. Ultimately you need to dig into the system to see what is causing the response that you find objectionable.

I have not worked with your exact components, but working with JBLs in general, the woofers are usually pretty well behaved and the vintage networks and many vintage JBL tweeters aren't particularly stellar.


Widget

[bedrock602]

I would run a FR curve of the system without the tweeter and then again without the woofer and see how each performs independently. Then based on that info, if I like what I see with each of them, and there is still a problem then I would try a network redesign because it is likely your problem.

Alternatively if the woofer or the tweeter is giving me the nasty peak, I might see if a network redesign can fix it. Ultimately you need to dig into the system to see what is causing the response that you find objectionable.

I have not worked with your exact components, but working with JBLs in general, the woofers are usually pretty well behaved and the vintage networks and many vintage JBL tweeters aren't particularly stellar.


Widget

That makes perfect sense, thank you.

[bedrock602]

I just found this...


http://audioheritage.org/vbulletin/showthread.php?p=93589

More test info at the bottom of that page.

JBL's cheapest contemporary compression driver would be a better choice for a two-way like L101. And once you abandon the potato masher, it's a whole new game.

Relying on LE14A for midrange up to 1.5 kHz is, uhmm, "marginal," as well.

http://manuals.harman.com/JBL/HOM/Technical%20Sheet/L101%20ts.pdf

It's one of the systems that gave LE14A an undeserved bad rep.

[Better than crossing to LE20 at 2 kHz, tho.... ;) ]

[Mr. Widget]

I just found this...I imagine I’d agree with Zilch’s comments, but I assume he was saying that there was a hole in the midrange, a suck out. I wouldn’t expect that to cause a speaker to sound shouty. Speakers with a shouty character usually have a midrange peak or excessive midrange distortion.

While not directly related to your speakers, in my experience using a midrange horn or HF horn that is to near its theoretical cut off frequency will cause a speaker to sound shouty. Many horn speakers exhibit this characteristic because larger horns take more real estate and cost more.

I suppose your tweeter may be exhibiting a similar phenomenon as it is asked to play lower than it should. Adding a midrange driver may solve your problem, but adding a driver to an existing system is not a trivial matter.


Widget

[bedrock602]

I imagine I’d agree with Zilch’s comments, but I assume he was saying that there was a hole in the midrange, a suck out. I wouldn’t expect that to cause a speaker to sound shouty. Speakers with a shouty character usually have a midrange peak or excessive midrange distortion.

While not directly related to your speakers, in my experience using a midrange horn or HF horn that is to near its theoretical cut off frequency will cause a speaker to sound shouty. Many horn speakers exhibit this characteristic because larger horns take more real estate and cost more.

I suppose your tweeter may be exhibiting a similar phenomenon as it is asked to play lower than it should. Adding a midrange driver may solve your problem, but adding a driver to an existing system is not a trivial matter.


Widget

Thank you for the thoughtful response.

My assessment of the quality of sound of the S99's is a result of a direct comparison between them and my main speaker system, the L110 which to my ears are superb sounding speakers. After years of listening to L88, L66, L77 and S99, the L110's at first seemed way too bright. But after a year or so of trying the L110's with various amplifiers they grew on me and now there is no turning back.

After doing some more reading about the LE14A and the various systems it was used in, I don't think that any reworking of the S99 crossover will improve them enough to replace the L110's. What I have decided to do instead is to remove the LE14A's from the cabinets and use them in larger enclosures for a three way system down the road.

The immediate project I have in mind is to utilize the S99 cabinets and modify the baffles to accomodate a 10" 3-way system, similar to the L110. I have a pair of LE10A's that need refoaming, a pair of LE5-2 and the tweeters will be the current LE20-1. The drivers will need to be tested, ports sized and crossovers designed but hopefully with the help of this forum I'll be able to work through it.

I appreciate all of the help so far, I have learned a little but hope to learn much more by tackling this project.

[short_circutz2]

I have a pair of S99's with LE14A and LE20-1. The woofers have new surrounds but otherwise all is original. The midrange is very "shouty" and unpleasant. Looking at the specifications and schematic of the crossover, the tweeters are crossed over at 2000 hz but it appears that the woofers run full range.

I'm a complete novice but doing a little reading about crossovers, it seems that upper end of the woofer can be controlled with an inductor. I think this would be a nice little experiment that can easily be reversed. If this is reasonable, can someone recommend a value, or range of values for an inductor to limit the woofer to 2000 hz or so? The tweeters and woofers are 8 ohms.

I have a pair of these. The only time I have ever had them sound "shouty" was before I chnged out the stiffened Lansalloy surrounds.

[Mr. Widget]

I have a pair of these. The only time I have ever had them sound "shouty" was before I chnged out the stiffened Lansalloy surrounds.Excellent point!


Widget

[bedrock602]

I have a pair of these. The only time I have ever had them sound "shouty" was before I chnged out the stiffened Lansalloy surrounds.


Excellent point!


Widget

I'm not sure why short_circutz2 simply stating that his experience is different from mine is an excellent point. He has the same speakers, but not the same amplifier, room, ears, etc.

I have some time this weekend and will do some experimenting. As I stated early on, I am a novice so my methods may be crude but I am open to suggestions and willing to learn. :)

[Mr. Widget]

I'm not sure why short_circutz2 simply stating....He brought up a possibility. Do your woofers have the original yellowed surround material or have they been updated with dark gray foam surrounds?


Widget

[bedrock602]

He brought up a possibility. Do your woofers have the original yellowed surround material or have they been updated with dark gray foam surrounds?


Widget

I established that the woofers have new surrounds in my first post.

[Mr. Widget]

I established that the woofers have new surrounds in my first post.Sorry, missed or forgot that.

That’s probably not the issue then. ;)


Widget

[bedrock602]

Sorry, missed or forgot that.

That’s probably not the issue then. ;)


Widget

No problem. I would like to get the most out of the LE14A's but I don't think that the S99 cabinet, crossover and tweeter are the best companions for it.

I had thought about building a S1 system but that gets expensive and from what I have read here, is not all that great either.

I would like a system that sounds as good as the L110's I have but with a little more bass for use in a larger room. The L110's are currently in a small listening room in the basement and are the perfect size for that setting.

[Earl K]

No problem. I would like to get the most out of the LE14A's but I don't think that the S99 cabinet, crossover and tweeter are the best companions for it.

I had thought about building a S1 system but that gets expensive and from what I have read here, is not all that great either.

I would like a system that sounds as good as the L110's I have but with a little more bass for use in a larger room. The L110's are currently in a small listening room in the basement and are the perfect size for that setting.


A great way to get familiar ( + intimate ) with the sound of your le14 is to ( indeed ) listen to it full range with a "smidge" of UHF ( mostly above 10K ) filling in the "air" .

This setup will allow you to focus on the midrange character of what that fourteen incher delivers and allow you to make some personal assessments.

Attach virtually any 4-8 ohm tweeter ( HiPassed with a simple 1uF cap ) and you will mimic the setup that I'm suggesting .

"Real-Life", it's pretty rough ( at least> visually ) above 1K .

http://www.audioheritage.org/photopost/data//500/Le14a-vs-Le14H-1_10019780934.jpg

Compare to a representative trace of a older Altec 414-8B ( which is showing higher THD, btw );

http://www.audioheritage.org/photopost/data//500/414-8B_10021419423.jpg



:)

[bedrock602]

A great way to get familiar ( + intimate ) with the sound of your le14 is to ( indeed ) listen to it full range with a "smidge" of UHF ( mostly above 10K ) filling in the "air" .

This setup will allow you to focus on the midrange character of what that fourteen incher delivers and allow you to make some personal assessments.

Attach virtually any 4-8 ohm tweeter ( HiPassed with a simple 1uF cap ) and you will mimic the setup that I'm suggesting .

I just happen to have some 1.0uF caps and will give it a shot.

[bedrock602]

But it sounds like I'm going deaf

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[bedrock602]

I removed the 1uF cap and replaced it with a 10uF cap to lower the crossover point and these S99's sound very lively with plenty of deep bass. Not as refined a sound as the L110 but maybe a properly designed crossover or simply a re-cap of the stock crossover would improve things.

[bedrock602]

I've had these B&C horns, Altec 806A's and N-800-F crossovers for some time and had considered using them with the LE14A's but in a larger cabinet. While I had the S99's apart I decided to try the horns with them as-is.

Huge, HUGE improvement over the LE20's and stock crossover. The low crossover point allows the woofers to do what they seem to do best, deep, clear bass.

84274

[Mr. Widget]

I've had these B&C horns, Altec 806A's and N-800-F crossovers for some time and had considered using them with the LE14A's but in a larger cabinet. While I had the S99's apart I decided to try the horns with them as-is.

Huge, HUGE improvement over the LE20's and stock crossover. The low crossover point allows the woofers to do what they seem to do best, deep, clear bass.Sounds like you are on the right track.


Widget

[bedrock602]

Sounds like you are on the right track.


Widget

Thanks, I hope so, as winding as that track may be :confused:.

My early assumption of the LE14A woofer not being a good match for the S99 cabinet was completely wrong. Listening to them crossed over at 800hz, they sound very, VERY good, so I will keep the woofers and cabinets together.

The B&C horns don't seem to respond that low, specs state they go as low as 1000hz and on music familiar to me, I can hear things missing. Also, at the top there is a bit of shrill. I dug out the 811B horns that came with the drivers and gave them a listen last night and this morning. The music is all there and very nice sounding but the horns can't live atop the S99's forever.

84279

[Mr. Widget]

Thanks, I hope so, as winding as that track may be :confused:.

My early assumption of the LE14A woofer not being a good match for the S99 cabinet was completely wrong. Listening to them crossed over at 800hz, they sound very, VERY good, so I will keep the woofers and cabinets together.

The B&C horns don't seem to respond that low, specs state they go as low as 1000hz and on music familiar to me, I can hear things missing. Also, at the top there is a bit of shrill. I dug out the 811B horns that came with the drivers and gave them a listen last night and this morning. The music is all there and very nice sounding but the horns can't live atop the S99's forever.Your discoveries align with my experience. The vintage JBL cone and dome tweeters and their crossovers are often not as good as the woofers.

You've also discovered that the better sounding horns are almost always larger than you would like. The 511B crossed over at 800Hz will sound even better, but it is even larger!



Widget

[sguttag]

You could use MRII994 Mantary horns and they'll sound yet better.

[bedrock602]

Your discoveries align with my experience. The vintage JBL cone and dome tweeters and their crossovers are often not as good as the woofers.

You've also discovered that the better sounding horns are almost always larger than you would like. The 511B crossed over at 800Hz will sound even better, but it is even larger!

Widget

Yes, 511B would be out of the question for this little room. A friend has a pair of "potato mashers" (he didn't say which model) that I will take a look at tomorrow.

My goal is to bring these S99's up to a level that would take the place of the L110. Whether I go with horns or cones, all of the components will need to live inside the enclosures.

[bedrock602]

You could use MRII994 Mantary horns and they'll sound yet better.

Thanks for the suggestion. I found an Altec catalog here that has those horns, unfortunately, they are way too big for my purposes. They're even bigger than the 811B's.

http://www.lansingheritage.org/images/altec/catalogs/1993-pro/1993-27.JPG

[sguttag]

Generally, size goes hand-in-hand with pattern control and loading, when tend to directly affect sound quality.

[Mr. Widget]

My goal is to bring these S99's up to a level that would take the place of the L110. Whether I go with horns or cones, all of the components will need to live inside the enclosures.In my opinion the potato mashers and other smaller horns are all a bit disappointing sounding. If the goal is to reuse the enclosures and keep all components in the boxes, I’d suggest going with cone/dome drivers.

If if it was my project I would look at the better drivers from some of the Scandinavian manufacturers or perhaps Morel.


Widget

[bedrock602]

In my opinion the potato mashers and other smaller horns are all a bit disappointing sounding. If the goal is to reuse the enclosures and keep all components in the boxes, I’d suggest going with cone/dome drivers.

I was thinking along the same lines.



If if it was my project I would look at the better drivers from some of the Scandinavian manufacturers or perhaps Morel.

Widget

Thanks for the advice, will look into Madisound and PE. If there are other sources for drivers and crossover components, please post them. :)

[RMC]

Hi Bedrock,

I've been looking at, and purchasing, European drivers for years...

RE: "If there are other sources for drivers and crossover components, please post them"


In addition to Madisound and Parts Express, you may also want to look at meniscusaudio.com and speakercity.com, both located in the USA too. Regards,

Richard

[bedrock602]

Hi Bedrock,

I've been looking at, and purchasing, European drivers for years...

RE: "If there are other sources for drivers and crossover components, please post them"


In addition to Madisound and Parts Express, you may also want to look at meniscusaudio.com and speakercity.com, both located in the USA too. Regards,

Richard

Thank you Richard !