JBL L Series (1990s)

[JBLAddict]

You guys and gals are taking this far too seriously, it's a beautiful day
(OK, I have U2 running through 2450SL w/Be on 2352 horns)...
it -is- a beautiful day.

Dome/JBLAddict, I received my 24/192 mic pre back from the shop...
if you -do- want to run ETCs or cal your mic's FR for L series + room
measurements, let me know.

-g

Re blackbird c... 90 tons of raw MDF to start with... that's a serious commitment.

wholeheartedly agree. decided to play some Bob Seger's Greatest on the L7s instead of measuring them, this is making me much happier

[Titanium Dome]

actually, this whole discussion came about regarding the bass coupling of the L7 to the walls, and how positioning does matter, and why JBL recommends 3' from the corners as a starting point.

The questions I'm trying to answer are:
1) Frequency response by speaker position
2) Frequency response by listening position
3) Whether treatment can reduce the sensitivity of the first two-- as purveyors of room treatments such as Real Traps go to tremendous lengths to demonstrate with videos loaded with actual recordings and measurement graphs before and after, that while serving a marketing purpose are pretty damn compelling

My goals are to determine whether:
1) Moving the speakers out in the middle of room is worth the obtrusion (since I'm not changing my primary listening position
2) I should spend a few hunny on bass traps in addition to the standard absorbing panels I've put in the room
3) I need new speakers

lastly, I think there's absolutely no doubt that an overabundance of VLF information gives the perception of recessed mid-range, mid-bass, and the L7 has that overabundance if not positioned and treated properly (compare my <100Hz measurements to that >100Hz). If you still owned L7s, take the tie bars off and plug only the top speakers in and see if they're still "recessed" once the <190Hz is removed--hint: the answer is NO

edit, I fully realize this thread may be too off-topic for L series, but since it's been a slow mover anyway, seems harmless as long as the measurments are L based

I'm all for keeping it here.

I was all for keeping that ^^^ here: JBLAddict's three questions and three goals. It seemed simple enough and on thread at the time. He asked for a reference, I gave it, and then...

JBLAddict, those Toole links were meant to be on thread, and they are. There's a lot in them that addresses your three questions and three goals.

I'll be taking a break now.

[BMWCCA]

I'll be taking a break now.

Not before a sincere vote of thanks for pretty much single-handedly elevating the '90s L-series JBLs to a level where they are taken seriously as a credit to their designers (thanks Chris Hagen) and lifting them out of their former Big-Box frame of reference.

T-dome's detailed appraisal piqued my curiosity enough to detour and pickup a pair of L5s which led me to a pair of L7s. That small-change adjustment to my JBL frame of reference is really responsible for my ultimate search and purchase of something I thought might even be better (and was) but I'd never have rekindled the interest in that part of my hobby without T-dome's enthusiastic support for the neglected L7 and L5.

Now go enjoy the Spring weather in that Maserati! Does yours sport the optional belt-drive CD player?

[JBLAddict]

thanks for the articles, I just finished reading the last of them. take a breath before moving too quickly was clearly the right advice

I say this because Floyd's articles cover so much ground, I'm fairly confused, as he doesn't (or intentionally avoids) make general recommendations that I can directly apply NOW. While I get that its a mix of the speaker, room, position, gear, treatment, it still seems to boil down to needing measurement capability to make any decisions.

Where I put my L7s, where I sit, and what I put on my walls, floors and ceilings, appears to require not only measurement but knowing what to do as a result. This is frustrating, as I sincerely want to make the most out of the system I have, but feel that the tools for doing so require expertise that is not realistically attainable. I'll pull em to 3' from the corners for critical 2ch listening because JBL said so, but for the fairly non-aesthetic panels adorning my walls I'm scratching my head not knowing if they're unecessary, or if actually adding treatment is worth pursuing??

your comment about considering the design of the L7 as a stereo vehicle makes sense, but I'm much less concerned with how my L series 5.1 is meeting "social" goals as Toole puts it, than I am blissful 2Ch experience for one listener (a.k.a. me). with this goal in mind, how would you recommend I go about optimizing the L7 around position and treatment only?

[localhost127]

While I get that its a mix of the speaker, room, position, gear, treatment, it still seem to boil down to needing measurement capability to make any decisions.

it is a breath of fresh air that you understand that concept so quickly! on some of the studio design forums im on, it's amazing how many want such a quick (and one-size-fits-all) answer, without so much as taking measurements to make clear what the issues in the room are that they even need to treat!

don't let the task daunt you. in small acoustical spaces, there are general guidelines to follow. but measuring first is important so you can see the direct (measured) improvement that treatments have made. we dont blindly place treatments, and we always take measurements to verify.

guidelines:
(1) as many and as deep of porous bass traps as you can in the corners (remember, 12 in a standard/rectangular room!).

you can make corner chunks like:
http://www.hometheatershack.com/foru...-finished.html

and

http://www.radford.edu/~shelm/acoustics/bass-traps.html

or you can stack the OC703 batts (usually 24"x48" in size), and straddle in the corner. the deeper the insulation (or the more spaced away from the wall) - the more effective the trap is. we're converting kinetic energy into heat --- so we want the insulation at areas of high particle velocity!

(2) broadband absorption at areas of early specular reflections. this eliminates comb-filtering from a reflected signal constructively and destructively combining with the direct sound at your ear (causing peaks and nulls).
you do *not* want a wooden frame around the insulation for these panels, as the edges will diffract. i build my frame behind the insulation (leaving the sides of the insulation exposed, a 50% increase in exposed surface area on a 4" panel!!) - which also spaces the insulation away from the wall 1.5", making the absorber more effective.

Where I put my L7s, where I sit, and what I put on my walls, floors and ceilings, appears to require not only measurement but knowing what to do as a result. This is frustrating, as I sincerely want to make the most out of the system I have, but feel that the tools for doing so require expertise that is not realistically attainable. I'll pull em to 3' from the corners for critical 2ch listening because JBL said so, but for the fairly non-aesthetic panels adorning my walls I'm scratching my head not knowing if they're unecessary, or if actually adding treatment is worth pursuing??

your comment about considering the design of the L7 as a stereo vehicle makes sense, but I'm much less concerned with how my L series 5.1 is meeting "social" goals as Toole puts it, than I am blissful 2Ch experience for one listener (a.k.a. me). with this goal in mind, how would you recommend I go about optimizing the L7 around position and treatment only?

you are more than free to investigate any modern control/mastering room.
LEDE/RFZ dominates this. absorption early reflections allows you to hear the direct signal, NOT your room. if i am listening to music recorded in a wonderful concert hall, why would i want to impose the sound of my tiny room on top?

as for surround sound (5.1 music), blackbird studio c ambechoic is the new the standard.. the evolution of the reflection free zone -




makes my PRD look puny in comparision



if you're interested in more, this is essentially the bible (schroeder diffusers, polys, helmholtz, limp membrane, bass traps, etc - you name it):
RPG (D'antonio) are the authorative figure on diffusers.

http://www.amazon.com/Acoustic-Absor...4377707&sr=1-2

a decent small room acoustical write-up (light-weight to read)

http://www.gcmstudio.com/acoustics/acoustics.html

[briang]

What a thread.

Room treatments are nice, but for the average Joe Bag-o-Donuts like me, that won't be happening.

I just picked up a set of L3 advertised on Minneapolis' Craigslist. I paid $120.00USD. The cabinets are solid, the drivers are good. Cosmetics need help on the front. I'll be sanding and repainting with a rattle can (and sanding, and repainting, and sanding, and repainting) the fronts to bring them up to accepable to me.

The L3 will serve rear channel duty in a 5.0 system in my living room.

[gferrell]

Nice score, the L3's are really good. They will blend in good as surrounds, what are you using for fronts?

[briang]

Nice score, the L3's are really good. They will blend in good as surrounds, what are you using for fronts?

L7 for Right and Left, and an old L86 as a center.

I have the components to build a center based on the L7 without the LE120H (i.e. I have spare 708g-1, 704g-1 and 035TIA with a pair of old L7 crossovers. I just need to get around to building a cabinet (probably will never happen).

[gferrell]

I did that and it turned out to be a great match. Movies are fun with 5.1 but I enjoy 5.1 for music most. It just takes some time to get the right balance. The L series just has a good all round timbre.

[JBLAddict]

I did that and it turned out to be a great match. Movies are fun with 5.1 but I enjoy 5.1 for music most. It just takes some time to get the right balance. The L series just has a good all round timbre.

have to give that a big +1

though from a time before HT, I think they do a super job on 5.1 music once powered and balanced correctly. as killer as TD's Performance setup sounds, when listening to my L setup within hours of hearing the PS, I'm really impressed how well they hold their own...and think it's the timbre that you point out as the strength

just received Gaucho DVD-A in the mail today, and have it running through the OPPO 83SE analog outs, and just, wow.......Genesis--We Can't Dance DTS 24/96 last week, another great MCH disc

[Slare]

What a thread.

Room treatments are nice, but for the average Joe Bag-o-Donuts like me, that won't be happening.

I just picked up a set of L3 advertised on Minneapolis' Craigslist. I paid $120.00USD. The cabinets are solid, the drivers are good. Cosmetics need help on the front. I'll be sanding and repainting with a rattle can (and sanding, and repainting, and sanding, and repainting) the fronts to bring them up to accepable to me.

The L3 will serve rear channel duty in a 5.0 system in my living room.

I had everything but L3's, so I can't make this statement very strong... but in case you haven't noticed there are two different finishes on the L series speakers.

The thin smooth black which was on the front baffles of my L5/L7's can be treated like auto paint, it polishes and buffs out nicely, and at worst case could be duplicated/refinished well enough with good rattle can work.

The grained surfaces have an almost wax like soft finish on them, and sanding on that with the goal of refinishing would be a nightmare. I'm not sure anyone has detailed an attempt at restoration of that finish yet. It may be better to just fill in the scratches in those areas with a repair crayon.

[gferrell]

I have thought about getting rid of the wear and tear on my set but it seems like quite a challenge. When I painted my center channel I used the rustoleum all surface satin black which is a very close match. I would like to see someone take on the challenge of refinishing a pair.

[JBL 4645]

I think you need to start your own thread on your system of sound absorbtion and treatments - this was a thread on 1990 L series speakers and your posts have nothing to do with that topic.


You are diminishing the original thread topic for anyone who comes looking for THAT information


If you are that informed about the topic, please start your own thread -
others may wish to hear of it IN THE RIGHT CONTEXT!

Thou me and Heather have disagreements with each other most times I have to say this thread is being steered off its original objective which is about JBL L Series (1990s).

Its nice to see JBL in room with skyline on the front wall but several pages about 101 acoustics come on.

I like peeking at picture show of other members JBL speaker set ups.

[JBL 4645]

if keeping the port uncovered is the biggest issue, up top works just fine...

I'll attach a basic pic to show the setup. Remember, the small J50s aren't hooked up. Just sitting there. I'd replace the SC305 with the L1.

I'm not sure floor space would work for me. Turning it upside down should remove the "problem" of it being angled, right? The port isn't going to be blocked up on top of the rptv. The second pic should show the difference in angle of having it right-side-up vs. upside-down.



that's kinda disappointing...but I've also read a lot of "reviews" that say the opposite of the ratings with Denon. Guess the only way to find out is to plug it up.

Either way, I know I'm not going to max it...so even if I'm using 50W of the Kenwood vs. 50W of the Denon, I'd like to think it's a bit better sound.

BTW...painting the wall black while the wife was out of town was loads of fun. It's been that way for >10 years now!! When you turn the lights out and the TV comes on, all the speakers and equipment just fade away. I've also thought about moving the L5s outside of the subs and angling them in a bit more.

Thing I noticed with model placed upside down is its kinder like what cinema surround speaker would be like JBL 83 series with sloping front baffle.

Maybe a whole cluster of these in room on sidewalls and rear wall upside down so the sloped edged baffle points downwards over the and around the setting area. Bet it puts out a reasonable bass/mid for smooth highs.

[gferrell]

Good deal on L7'S

http://raleigh.craigslist.org/ele/2409073757.html