Did I do something foolish.... ? ;)

[RedCoat23]

I just saw a bit of a bargain on fleabay...

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=150630184388&ssPageName=STRK:MEWAX:IT

So I took the plunge. I mean the drivers alone cost more than that...

Someone sooth my conscience! :D

Redcoat.

[Rusnzha]

You got a hell of a sub at a nice price. This box has 2 2241h subs. The 2241h is going for $797 each at Parts Express. Got to love the math. :applaud::applaud: I'm using one of these and the bass from it rules.

[RedCoat23]

It's rare these days to see a bargain on ebay - I primarily use it to keep an eye on current market values. Which is why I did such a double take on this.

I've absolutely no idea where I'm going to put it right now...:blink: But it's a nice problem to have.

[JBL 4645]

It is rather deep! :D Good buy they usual cost around £1500.00 then again that model has been out for years now.

You could stand it upright with its back on the floor so the twin 18” are facing upwards lows are supposedly omni-directional. Keep it located centred in the room if possible as some lows will draw you’re attention to one side all the time which is annoying to listen to if you don’t have multiples of them to balance the lows out evenly so that they arrive on both sides of you’re ears rather than hearing 60Hz on one side all the time.

[Rusnzha]

Originally posted by JBL 4645

Keep it located centred in the room if possible as some lows will draw you’re attention to one side all the time which is annoying to listen to if you don’t have multiples of them to balance the lows out evenly so that they arrive on both sides of you’re ears rather than hearing 60Hz on one side all the time. Not so, I got mine in the corner where with a little EQ it goes flat down to 15 Hz. As long as there is a good volume balance between the sub and the rest, it's a thing of beauty. None of the described issues ever pop up unless there is excessive sub-woofer volume. It might be an old model, but these speakers will still sound great in the next century. It will give you more natural sounding, tight, bottomless bass than you will ever need. Especially with 2 of them. If you got the room, it will be more efficient with both woofers close to the floor and in a corner. It will stay strong into the subsonic range.:dj-party:.

[tomt]

Originally posted by JBL 4645
Not so, I got mine in the corner where with a little EQ it goes flat down to 15 Hz. As long as there is a good volume balance between the sub and the rest, it's a thing of beauty. None of the described issues ever pop up unless there is excessive sub-woofer volume. It might be an old model, but these speakers will still sound great in the next century. It will give you more natural sounding, tight, bottomless bass than you will ever need. Especially with 2 of them. If you got the room, it will be more efficient with both woofers close to the floor and in a corner. It will stay strong into the subsonic range.:dj-party:.

so,

where did you set the (upper) xover freq?

[Rusnzha]

80Hz

[lgvenable]

Drive the speakers at 1200 to 2400 continuous WPC and you'll have infrasonic bass at 15 HZ like no one's business. Be sure to get the right size amp, as under powering them can damage the drivers too. I have two single drivers subs with 2241H's. I can shake the whole end of my 3200 ft2 home both floors without even stressing my amps.

http://www.jblpro.com/pub/obsolete/4645b.pdf

My local JBL reconer who also does pro sound in the Evansville area always stresses the need for theater amps where the amp is on at max output and you set the gain to match the speaker.

I've got AB System 821 theater amps for each which are 600 WPC but once rebuilt and optimized by a local sound engineer were putting out closer to 750 WPC; and were inexpensive too..less than 100.00 each, then and additional 150 in charges for power transistors and replacing all the caps yielded bass response like crazy.

Then again you can find BGW 750 B/C/D/E for 250.00 to 400.00 each that when bridged will deliver the same kind of power. I guess if you buy the newer amps (QSC etc), they'll have max power too, its just that the older stuff is rebuildable. That and I'm old school.

On the 750B's I got lucky and found a pair cheap on Craigslist that came out of a University radio station, they were in perfect shape, with led analog meters (look great in the dark when powered up) and were in mint shape to the eye; two for 275.00.

My wife says I'm a little nuts, as I have both the AB System amps and the Sensurround BGW 750B's. Makes for a great backup sitting in the closet. Once I rebuilt the AB Systems they've been like the Energizer bunny they just keep running; and dead quiet too.

My issue with the new smaller (QSC etc) amps have boards that are wave soldered in them, which is one of the ways they reduce their footprint. Once they break, throw them away, as its cheaper to get a new amp than getting new boards.

[RedCoat23]

Well it turns up on Tuesday...I was looking at some Crown XTI series so I can set crossover frequencies...anyone have an opinion on them or should I look elsewhere?

[Rusnzha]

Originally posted by RedCoat23

Then again you can find BGW 750 B/C/D/E for 250.00 to 400.00 each that when bridged will deliver the same kind of power. I guess if you buy the newer amps (QSC etc), they'll have max power too, its just that the older stuff is rebuildable. That and I'm old school.


I was real happy with a Hypex HS-500 subwoofer amp. Unfortunately, it's in the shop right now. I got them schematics and layout diagrams for all the boards. They didn't sound to sure if they could fix it. If I have to replace, looking at QSC, Crown and Crest. I suspect, I'll be better off with the older stuff. I hope I can get the hypex going again. If I can't, will check out the BGW also. Any other recommendations?

[pos]

Drive the speakers at 1200 to 2400 continuous WPC and you'll have infrasonic bass at 15 HZ like no one's business.
It is dangerous to drive these high efficiency/low excursion drivers lower than the tuning frequency with too much power. It is higly recommanded to use a HP filter at (or just below) this frequency. One solution for domestic usage is to lower the tuning frequency and use a resonant HP filter (Q>1), as in the B460, trading power for excursion at VLF.


Be sure to get the right size amp, as under powering them can damage the drivers too.
That is quite unlikely with a subwoofer, unless the amp burns and send DC to the driver.
Under powering is only dangerous for full range speakers in mono amplification, where harmonic distortion can bring too much power to the tweeter.

[Eaulive]

That is quite unlikely with a subwoofer, unless the amp burns and send DC to the driver.
Under powering is only dangerous for full range speakers in mono amplification, where harmonic distortion can bring too much power to the tweeter.

Thanks, I grow tired of repeating it :D

[JBL 4645]

Originally posted by JBL 4645
Not so, I got mine in the corner where with a little EQ it goes flat down to 15 Hz. As long as there is a good volume balance between the sub and the rest, it's a thing of beauty. None of the described issues ever pop up unless there is excessive sub-woofer volume. It might be an old model, but these speakers will still sound great in the next century. It will give you more natural sounding, tight, bottomless bass than you will ever need. Especially with 2 of them. If you got the room, it will be more efficient with both woofers close to the floor and in a corner. It will stay strong into the subsonic range.:dj-party:.

It really does take two to tango ;) three better four even better six miles better eight perfect :applaud: providing levels are within the same as LCRS it should smoothly morph into the next channel with minimal dips and jumps, that’s key to whole thing.

Reproducing what is on the soundtrack. You can’t not boast what is on the soundtrack and expect a film like STAR TREK (2009) with warp drive effects not bottoming out the sub with +20 30db levels on single sub, you’ll wreak it!

[JBL 4645]

so,

where did you set the (upper) xover freq?

Anyone that knows, knows I don’t have second DCX2496 to handle the JBL sub its only running as is straight from the AVR to MDX4600 if I wanted to use some compression or audio limiting then onto Behringer FBQ2496 PEQ then onto Alesis RA300.

Most LFE.1 is cut off in and around at 120Hz where it goes from below 20Hz on some mixes is nether here or there because very few films seldom go below 20Hz they drop off ether around 30Hz or 25Hz or shallow rapidly or have been drastically ruined by filtering off the low end with 30Hz cut that is suited for films in 70’s and 80’s some films are mixed restricted some come around in once in while that goes way, way down near 5Hz or lower and there is nothing there to get excited about you can’t hear it! Felling it LOL The rest of the upper lows will mask it because the levels will be higher and the ear is going lock on to those notes.

Plus its 14 years since I got the box home and loaded up and not day has gone by with any major snags. I’ve just be lucky where others blow there sub up in there home theatre basement within a couple of weeks.

[Rusnzha]

Originally posted by JBL 4645
Reproducing what is on the soundtrack. You can’t not boast what is on the soundtrack and expect a film like STAR TREK (2009) with warp drive effects not bottoming out the sub with +20 30db levels on single sub, you’ll wreak it!

Did this thread get hijacked? Sorry!! I built my system mostly for music, but I watch movies on it too. If you play it loud enough, yes, something bad can happen to your sub. As long as you have some headroom, I can't see why it would be a problem with a speaker as capable as the 2241H and sufficient power.

[JBL 4645]

Did this thread get hijacked? Sorry!! I built my system mostly for music, but I watch movies on it too. If you play it loud enough, yes, something bad can happen to your sub. As long as you have some headroom, I can't see why it would be a problem with a speaker as capable as the 2241H and sufficient power.

Whoops sorry!

Yes headroom I agree.

But its no good if you have nulls standing between you and the sub no good at all it takes more than one sub to cut around Mr. Null one sub might be good for 20Hz to 40Hz then shallows down like in my room then sub number 2 is good from 40Hz to 100Hz splice them together and bingo sorted!:)

Placing subs at the front in cluster in my room is no good it will only add up where its good and suck where Mr. Null is sucking away on my subs that looks like The Mariana Trench. Placing several at the back is only good for 40Hz to 100Hz so spread them around we don’t have large cinema rooms. We have living rooms.:D

[Rusnzha]

Originally posted by JBL 4645

But its no good if you have nulls standing between you and the sub no good at all it takes more than one sub to cut around Mr. Null one sub might be good for 20Hz to 40Hz then shallows down like in my room then sub number 2 is good from 40Hz to 100Hz splice them together and bingo sorted!:)

Placing subs at the front in cluster in my room is no good it will only add up where its good and suck where Mr. Null is sucking away on my subs that looks like The Mariana Trench. Placing several at the back is only good for 40Hz to 100Hz so spread them around we don’t have large cinema rooms. We have living rooms.


That makes sense, you have some interesting problems. I got a good curve in my main listening position :D:applaud:, so no problem, but it sounds like you needed a more creative solution. I'm lucky mine works as is since I don't have the space or budget for more subs.

[JBL 4645]

That makes sense, you have some interesting problems. I got a good curve in my main listening position :D:applaud:, so no problem, but it sounds like you needed a more creative solution. I'm lucky mine works as is since I don't have the space or budget for more subs.

Oh, some are just lucky. :D

Well it’s just figuring it all out and I know what to do in my living room now after look at the frequency graphs till blue in the face.

I could move the seating forwards but the lower end drops of I could move the seating back towards the rear but the lower end gets too damn high the rest of the range starts to fill in. Its going to fun re-eq’ing the room once all the seats go in because some seats for the back is going to be pig to eq so it’s not incomparable.

[jbl_daddy]

It really does take two to tango ;) three better four even better six miles better eight perfect :applaud: providing levels are within the same as LCRS it should smoothly morph into the next channel with minimal dips and jumps, that’s key to whole thing.

Reproducing what is on the soundtrack. You can’t not boast what is on the soundtrack and expect a film like STAR TREK (2009) with warp drive effects not bottoming out the sub with +20 30db levels on single sub, you’ll wreak it!

The part in star trek you are talking about bottomed out all four of my b380's and scared the crappy out of me. Ps. They are powered by a pair of crown k2's.

[JBL 4645]

The part in star trek you are talking about bottomed out all four of my b380's and scared the crappy out of me. Ps. They are powered by a pair of crown k2's.

Yeah be careful with that film its got potential to damage loudspeakers and should carry warning sticker on DVD bluray by the studio who don’t seem to care that much but if one is sheer careless the studio shouldn’t be held reasonable unless there turning out crappy transfers and this one is nice hands down.

I must have used ¾ of the power during warp drive scenes and I knew that was far too much 1/3 more I’d be clipping the amp and its small room if I didn’t have the shallow sloping null the response would be hard around the 30Hz to 60Hz range uniformly and you don’t need wads of watts to prove how loud you’re sub can play in small room. In large cinema I’d be interested to know how much the whole x16 JBL 4645C subs used at the Empire its limit is 20KW on the subs and those Crown’s do a wicked job.


Down loud Spectrum Lab (its free and easy to use) and get some long RCA phone leads and look at each LCRS/LFE.1 output from e AVR then use mic and see how well it mirrors in the room. If can see how much I have then I need to cut back on the frequency if I see less and see how much power I’m using I need to cut back on the level until I get it sorted otherwise I stand the risk of damaging the sub as I'll be feeding far too much where its not needed.