Help with fomo - JBL 4645C Subwoofer

[sahil fardeen]

It does what it's supposed to do !!

sure yes
only issue is amp headroom now
will opt for xti 4002

 

[Rahan]

I think the xti 2002 would do the job. Don't you think?

You need to do something about the 50hz region!! Have you tried other placements?

 

[sahil fardeen]

I think the xti 2002 would do the job. Don't you think?

You need to do something about the 50hz region!! Have you tried other placements?

Difference between 2002 and 4002 is just $80 here in India. Makes a lot of sense to go for 4002

And yes placement I thank god that atleast i have this response now. Just one dip at 50hz, cant even imagine moving the sub. Sub is placed dead center in the front wall of the room to avoid any localisable bass. Else i can always tell where the bass is if its on the sides

 

[smygolf]

Depending on how loud you play you can use a target curve that slowly increases bass instead of a B6
With HPF the trouble region will be ~30-35hz.

Very interesting to see what a baffle wall can do for a speaker.

Thank You for the measurements

 

[smygolf]

Difference between 2002 and 4002 is just $80 here in India. Makes a lot of sense to go for 4002

And yes placement I thank god that atleast i have this response now. Just one dip at 50hz, cant even imagine moving the sub. Sub is placed dead center in the front wall of the room to avoid any localisable bass. Else i can always tell where the bass is if its on the sides

Can very well be room mode dependent

 

[sahil fardeen]

Can very well be room mode dependent

I would say otherwise
i have tested countless number of times with plenty of single subs, and could always tell where the bass is coming from if placed either left or right. Best way to avoid this is either place the single sub dead center so its symmetrical, or use a very low crossover point to the mains(even then the bass seems to sound/hit from one side with the low xover point too)
Every time i have tested this previously , the single sub had no major dips/peaks in response, it was relatively flat, so its not the room mode thats making it sound like this

 

[sahil fardeen]

But the corner placement along front wall could have helped a lot in getting the natural B6, it would imitate the 1pie/baffle wall condition

 

[sahil fardeen]

Depending on how loud you play you can use a target curve that slowly increases bass instead of a B6
With HPF the trouble region will be ~30-35hz.

Very interesting to see what a baffle wall can do for a speaker.

Thank You for the measurements

Welcome, always

Yep, this speaker is specifically designed to take boundary gain/baffle wall into advantage. Thats how most theatres achieve “free” bass below 40hz. Essentially they have a very rugged and huge baffle wall and multiple units of 4645c that helps them even more

 

[sahil fardeen]

Depending on how loud you play you can use a target curve that slowly increases bass instead of a B6
With HPF the trouble region will be ~30-35hz.

Very interesting to see what a baffle wall can do for a speaker.

Thank You for the measurements

Yep, always prefer a rising response to the lowest octave. Previously I had used 150hz LPF which had the response rising upward like crazy in the 60-120hz region. That yielded me a lot of upper bass boom. Didn’t sound that great. Now with 80hz LPF it sounds fantastic.

 

[Rahan]

If you can localise the sub with a 80 LPF there is a problem somewhere. 80Hz is unlocalisable for the human ears into a room. Bad subs are eazy to localise because they have hight harmonic distorsion. For exemple the 2nd HD of 60Hz is 120 Hz. But the 2242h is a really low distorsion driver. Mine just acoustically disappeared.

When you were able to localise it, did you crank the volume really high?

What slope are you using in you low-pass?

Btw, I'm glad you like how it sounds!

 

[sahil fardeen]

If you can localise the sub with a 80 LPF there is a problem somewhere. 80Hz is unlocalisable for the human ears into a room. Bad subs are eazy to localise because they have hight harmonic distorsion. For exemple the 2nd HD of 60Hz is 120 Hz. But the 2242h is a really low distorsion driver. Mine just acoustically disappeared.

When you were able to localise it, did you crank the volume really high?

What slope are you using in you low-pass?

Btw, I'm glad you like how it sounds!

Always, sub is cranked. That shouldn’t even be a question xD. 2 subs just sound way more cohesive and less pointable. I have also read various theory that bass below 150hz is unlocalisable. It may be true in pure sense but you have the whole room move along with the bass so that reveals its location. Very Very complex topic, but this is my conclusion
LPF at 90-100hz works great with mains crossed at 80hz. Else i could get an ugly upper bass boom from the sub.

 

[sahil fardeen]

Well if you are just adding a bottom end/using sub at a very low level/sub is perfectly level matched(ideally sub should be hotter due to nature of human hearing) you shouldn’t have a problem localising a single sub. What does seem localisable is when you have it cranked. That’s only avoidable using a single sub by keeping it dead center of the room

 

[sahil fardeen]

10/10 times i even preferred the sound of dual subs placed left and right with a bad response than with a single sub, ideally placed, along left or right, with a very flat response

Duals sound way more cohesive even if the response is not flat

 

[Rahan]

Well, I guess you've just never experienced a good sub integration. With a well done set up you're not even supposed to know there is a sub working. Anyway, if your setting matchs your personal teast, this is perfect.

 

[sahil fardeen]

Well, I guess you've just never experienced a good sub integration. With a well done set up you're not even supposed to know there is a sub working. Anyway, if your setting matchs your personal teast, this is perfect.

Well, everything is subjective in audio
Good to hear your opinion

 

[Puddingbuks]

I have a JBL 4281F subwoofer in my home cinema, combined with two Monoprice Monolith 15 subwoofers. Powered by a crown xls 1502. The -20db leds rarely come on.

It certainly delivers, high sensitivity helps a lot, they deliver slam and pressure, albeit not in the lowest sub bass department. Although it is pretty big, the rather shallow cabinet makes placement easy. It is cheaper than a 4645c btw.

https://jblpro.com/th/site_elements/4281f-spec-sheet

 

[DBA ndreas]

You could block two of the four ports for deeper tuning to reach the lowest octave with still plenty of headroom.

 

[Rahan]

I love the shape of the cabinet. I don't know what driver it use. I can't find the info.

 

[sahil fardeen]

I have a JBL 4281F subwoofer in my home cinema, combined with two Monoprice Monolith 15 subwoofers. Powered by a crown xls 1502. The -20db leds rarely come on.

It certainly delivers, high sensitivity helps a lot, they deliver slam and pressure, albeit not in the lowest sub bass department. Although it is pretty big, the rather shallow cabinet makes placement easy. It is cheaper than a 4645c btw.

https://jblpro.com/th/site_elements/4281f-spec-sheet

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For your info i was in a lot of dilemma between these newer jbl subs(cinema expansion series)and the 4645 when i was making the purchase decision.
The 4281F you own was out of question for me as its too big, depth not an issue for me since i have an AT setup.
So i was very much in dilemma between 3181F vs 4645C
I could also get 2 3181F and still be less than the cost of single 4645C. But the only thing that was making me worried about this was the low frequency extension.
-3db point at 38hz and -10db@30hz. I tried to do a lot of searching but haven’t even found a single review about this 3181F.
Ultimately, I got to get the frequency response measurement from the driver(the woofer used is jbl selenium 18”)

The output difference below 40hz between the 3181F and 4645C is enormous. It would even take more than 4 subs to match the output of a single 4645 below 40hz. Above 40hz a single 3181F will be very identical to both 4641 and 4645C.

I even did an excel measurement between the 3181 and 4645C. Calculated, theoretically, there is more than 10-15db difference in output in 20-40hz region.

So finally i decided to opt for a single 4645C and decided if necessary, will add a second one later on. Haven’t regretted the decision even a bit

 

[Puddingbuks]

I regret not buying the 5628, I knew a guy who could sell these JBLs with a nice discount. It digs way deeper. Could get it in 2021 for 2.500 euro. 4645c for 1.200. 4642a for 1500.

But I still like the 4281F, it looks great, and price performance is fantastic. The bass really kicks and has impact with little power used.