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Can A Scientist Tell Me Why My High End Speakers Sound Dramatically Better Crossed Over At 120hz?

jhaider

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No matter how good is your speaker, 5" woofers can only do so much.

Here, you’d be surprised. Keep in mind that by the measurements JBL 705 is capable of higher output than JBL 308!

The issue here is room/placement related, not speaker related. There’s no reason in that setup not to use the crossover to work around such issues, so the higher cross (which is generally speaking my default) is a great fix.
 

Jim Matthews

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I use a similar crossover point with my JBL 708p.

Nothing more than a SWAG, here : reduced port output from the mains.
Mine are crossed at 160 Hz. Upright Bass sounds natural, male voices aren't emphasized, Hammond B3 is energetic but not to the point of oscillation.

As mentioned above, placement near boundaries and room modes are variable - I suspect one of the difficulties we now face is de-emphasis of boosted recordings made before small drivers could "dig" so deep.
 

Pdxwayne

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Here, you’d be surprised. Keep in mind that by the measurements JBL 705 is capable of higher output than JBL 308!

The issue here is room/placement related, not speaker related. There’s no reason in that setup not to use the crossover to work around such issues, so the higher cross (which is generally speaking my default) is a great fix.
Hmm....Are you saying that if OP is using an excellent large 3 ways in the same room and same location, he will still need same high crossover to sound good?
 

Pdxwayne

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Entirely possible, yes. Rooms don’t care about your plans.

Yeah, your points can be fully valid, but....
First of all, you don't know what is going on in OP's room....

Secondly, regarding using high crossover point, when did you last see any member mention they have large speakers? So far I have read about this one and KEF LS50, which is another 5" woofer speaker.

Thirdly, I have two 5.1 setups and 4 stereo setups in 5 different rooms in various sizes. I have played with speakers with 5", 7", and 10" woofers, placed in same room and same location. Yes, 5" crossed high most of the time sounded much better than crossed low. Less so with 7" and 10" woofers speakers.

Please share your own experience with us. What size speakers have you used?
 
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jhaider

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First of all, you don't know what is going on in OP's room.

I do know the loudspeakers at issue well.

Secondly, regarding using high crossover point, when did you last see any member mention they have large speakers?
So far I have read about this one and KEF LS50, which is another 5" woofer speaker.

There is at least one person above who notes using a 120Hz crossover with markedly more capable mains. I also write from personal experience.

Thirdly, I have two 5.1 setups and 4 stereo setups in 4 different rooms in various sizes. I have played with speakers with 5", 7", and 10" woofers, placed in same room and same location. Yes, 5" crossed high most of the time sounded much better than crossed low. Less so with 7" and 10" woofers speakers.

While I don’t doubt that, I assure you none of those 5” speakers were this capable. Again, note that in Sound und Recording’s measurements this pint sized wonder had more bass capability than the 8” woofer model in JBL’s lower line. Depending on listening distance and SPL expectations your observations make sense.

Please share your own experience with us.

I currently use JBL 708 with multiple subwoofers. A 120Hz crossover happens to provide the objectively smoothest and subjectively most enveloping bass. Previously I used loudspeakers with two 7” woofers flanking a coax. The same was true then, in this room. In a different room things may work out very differently.
 

Pdxwayne

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I do know the loudspeakers at issue well.



There is at least one person above who notes using a 120Hz crossover with markedly more capable mains. I also write from personal experience.



While I don’t doubt that, I assure you none of those 5” speakers were this capable. Again, note that in Sound und Recording’s measurements this pint sized wonder had more bass capability than the 8” woofer model in JBL’s lower line. Depending on listening distance and SPL expectations your observations make sense.



I currently use JBL 708 with multiple subwoofers. A 120Hz crossover happens to provide the objectively smoothest and subjectively most enveloping bass. Previously I used loudspeakers with two 7” woofers flanking a coax. The same was true then, in this room. In a different room things may work out very differently.

Sure, your observation about room is valid for your case. I have similar observations in my rooms too. This is "one" very good explanation as to "why".

That said, there is another issue of room size and listening volume. That was my other "why". I have a very capable 800rms watts 10" sub that sounds great in my small rooms. But when used in my big 5000+ cubic ft room, it got "loss" trying to play loud. My 1650 RMS watts 15" sub, on the other hand, in same location sounds just fine.
 
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Thomas_A

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The primary is to look at the acoustic integration HP/LP at 80 vs 120 Hz. Are there near-field measurements to view? Second is probably room, SPL/distortion or both.
 

Xulonn

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No, of course not! "SCIENCE" is not a bunch of "THEORIES"

And of course, you must be aware that the acronym "SWAG" is an oxymoron, but that is all we can offer for the OP without measurements. I take it (SWAG) to mean a best guess based on logic, practical experience and known principles, but without having sufficient knowledge of the situation and limited data.
 

Jim Matthews

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I take it (SWAG) to mean a best guess based on logic, practical experience and known principles, but without having sufficient knowledge of the situation and limited data.

Quite right. I'm most definitely out of my depth.
That said, the crop of affordable processors makes testing a variable like this (crossover point) simple enough.

My concern is that the presumption any given processor can correct any misbehaving transducer can be both expensive,and disappointing.

In my opinion this falls short in large, irregular rooms with poor acoustic foundations. These gizmos can do a great deal, but they have limits.
 

Mike Lima

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Sorry for the newbie question, but in REW how do you determine a speaker's crossover in relation to a sub?

Do I measure the front Left and Right speakers without the SUB ... then run the aligned subs separately? Should they intersect? Is that how to determine crossover?

I have a basic Andrew Jones Pioneer SP-FS52 up front and SP-BS22-LRs as surrounds mated with an Infinity Reference RC263 as my center. I also use 3 pretty basic Dayton Sub1200s.

Can you point me in the right direction? Thank you.
 

Chrispy

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What do you mean "a speaker's crossover"? A crossover is that very intersection between low pass and high pass filters for sub/speakers. Or do you mean the speaker's internal crossover between drivers via the passive network?
 

Mike Lima

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What do you mean "a speaker's crossover"? A crossover is that very intersection between low pass and high pass filters for sub/speakers. Or do you mean the speaker's internal crossover between drivers via the passive network?
i meant the crossover between sub and speakers.
 
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