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For those interested in the JBL 4638 woofers...


CharlieTuna

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They are in stock today. I just posted to the thread:

WORST subwoofer out there:

With some order insight. Make sure you order through their website:

http://www.jblpro.com/Tent_Sale/sale_items.htm

Good luck!

CT

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You can tune a radio, but you can't tuna fish!

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Hell no! It is the cabinet, the 2, 15" woofers installed in the cabinet, and the input terminals. There is no crossover. ALL you need to do is get a powered bass signal going into the cabinet and you have a very powerful subwoofer.

To reiterate, take a normal subwoofer (like a KSW-15) and take the amp out, replace the amp with normal speaker inputs and thats what the JBL 4638 is.

You will either need a subwoofer amp (like my powerful, $130 Parts Express amp) or a subwoofer output with a normal power amp. After that, you are clear for liftoff...

Ask anymore questions here or one of my other subwoofer posts.

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ok, w/ teeth clenched i'm starting to consider this. i mean only because i had declared a truce w/ the budget.

cwm35.gif

but these do look to be great deals w/ a fine company &

product.

the only way i would go would be if it works well using

the marantz sr8000 sub preout (fixed cross at 80hz). wonder how this would sound??? if i read tom's posts right the plate amp that krb also got has a variable cross control built-in.

also, i'd wanna use my old kenwood kr9600. vintage 1975, 165WX2 into 8 OHMS & has power inputs. baby packs some current but wonder how it'd fare on a 4 ohm load. could be it's last harrah??? or would it even drive them well?

it's just that i've spent so many $ just this year already. maybe i should just say what the ___ & get the 4638. & then try to find a place in the lounge to put the beast. cwm5.gif

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Ready and willing edster00.

boa12, you could probably resell it for $300-$500+ later, after they sell out, heck (I probably need to stop the cussn') pull the woofers out and sell them on eBay for $150-$200 each!

The money part is up to you. As for the 80Hz X-over, it should be OK. Yes, the plate amp has a 40Hz-160Hz variable croosover. Also a phase adjestment from 0-180 degrees. It is very well build. However, the high-level input banana plugs are a little dinky (gold plated) but most people don't use the high-level inputs anyway.

Dose anyone know about the X-10, X-20, and X-30 subwoofer croosovers Paradigm makes are like? They are pretty cheap and might be the bridge between a full spectrum output and an amp for a sub.

This message has been edited by kenratboy on 02-25-2002 at 05:53 PM

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thanks krb. i too think it would work ok using the 80hz low pass & high pass on my rf-3 (by setting them small in the marantz). & no doubt they'd put out better bass in that 30-80hz range.

imo you wouldn't need an outboard crossover w/ what u have on the p-amp. i however probably would for fine tuning using my big ken as the amp.

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thanks

anyone know what power is required to make these sing? could they be powered, say, by an old prologic receiver, for example?

also, the specs don't look really impressive, but I assume they are underspec'ed, aren't they? I mean, a sub that doesn't go lower than 30Hz efficiently hardly seems like a good deal for home theater use...

to those with practical experience, exactly how low can they go in a typical room?

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Can someone (HornEd, maybe) look at the specs on page 2 and interpret what is meant by:

"4638 system half-space (2 PI) response, one watt at one

meter on-axis; impedance."

"4638 system half-space (2 PI) response, 10 watts at one

meter on-axis; distortion raised 20 dB."

"4638 system half-space (2 PI) response, 100 watts at one

meter on-axis; distortion raised 20 dB."

Is this the SPL/Hz performance based on the above mentioned supplied power? Doesn't make sense for one or ten watts.

CT

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=====================================

You can tune a radio, but you can't tuna fish!

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FACT: This subwoofer, in a room, will go below 25Hz. The way they measure the frequency responce is "open space" like if it was in the middle of a feild (like grass and flowers)

These are hi-quality 15" woofers, they are not being limited or they are not build to stop at 35 or 45 Hz, so don't sweat it. Also, even if its LOUD to your ears, the rated frequency responce is at a level that could not be tolerated in a small room (NOT a movie theater)

You may not be able to get 15Hz from these things, but they hit hard and go deep. That was my biggest concern when I got it, but I love them now.

Get these babies in the corner and they REALLY sing. Also, if you have a w00d-framed house and non-slab floor, it really shakes you.

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quote:

You may not be able to get 15Hz from these things, but they hit hard and go deep. That was my biggest concern when I got it, but I love them now.


Uhhhhhh? I said they probabely won't be able to get down to 15Hz. Tom B. said he has one of those fancy pants spectrum analyzers and that the lowest frequency the gague COULD MEASURE was 25Hz. I would assume that the sub could go lower that the well-measured 25Hz, even though I didn't say that Smile.gif.

To be honest, I don't know what the 4638's are able to do. On JBL's info, they are the same from a frequency responce level, but they are not able to handle as much power. From that, I would think they were caplible of the same frequency responce as the 4648A-8.

Again, these woofers are not casterated of their low frequency. They are capable of low bass output. ALSO remember, the quieter you play them (not the levels they use in cinemas, like larger room means more volume to get X dB than in a living room) the easier of time they will have getting into the teens of frequency responce.

I have no doubt that some subs could go lower, but not much more that 5 or 10 Hz.

Remember, this is $216. Try to find a better sub for the money. Thats the WHOLE reason we are having these conversations. Hey, its not going to be perfect, but for the money, its a awsome value.

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