Bass Response. Need Advice!

[Bghead8che]

OK. Here are two different reviews and measurements of the Definitive 8080ST and Definitive Technology 8060ST:

Go to hometheater and search for Definitive Technology to find the review.
Go to soundandvisionmag and search for Definitive Technology to find the review.

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I am confused on the bass response. The HT review shows the 8080ST as having bass response down -3db at 35HZ (not exactly "full range").

S&V however shows the 8060s (the lower model) as having bass response from 20hz to 3.15 of 103.6 DB which is very respectable. Commenting on the bass response of the 8060s they said:

"The subwoofer section of the BP-8060ST is fairly kicking given the speaker’s compact size. Low bass output (40-63 Hz) averages 110.5 dB and ultra-low bass (20-31.5 Hz) output averages just 103.6 dB — numbers that put some midsize subwoofers to shame. It’s not distortion that limits the useful output in this case but either mechanical noise from the woofer cone or the amplifier’s internal limiter stepping in to protect the driver."

I am confused by the huge discrepancy is measurements. How can one show a -3DB point at 35hz and the other showing 103.6 DB all the way down to 20hz?

Also, obviously the bass response is for one speaker. Running two speakers how much more DB can you expect from 20HZ to 40HZ?

Any thoughts on the why the numbers could be so different and which "correct"?

Thanks,

-Brian

 

[anamorphic96]

OK. Here are two different reviews and measurements of the Definitive 8080ST and Definitive Technology 8060ST:

Go to hometheater and search for Definitive Technology to find the review.
Go to soundandvisionmag and search for Definitive Technology to find the review.

-----------------------------------------------------

I am confused on the bass response. The HT review shows the 8080ST as having bass response down -3db at 35HZ (not exactly "full range").

S&V however shows the 8060s (the lower model) as having bass response from 20hz to 3.15 of 103.6 DB which is very respectable. Commenting on the bass response of the 8060s they said:

"The subwoofer section of the BP-8060ST is fairly kicking given the speaker’s compact size. Low bass output (40-63 Hz) averages 110.5 dB and ultra-low bass (20-31.5 Hz) output averages just 103.6 dB — numbers that put some midsize subwoofers to shame. It’s not distortion that limits the useful output in this case but either mechanical noise from the woofer cone or the amplifier’s internal limiter stepping in to protect the driver."

I am confused by the huge discrepancy is measurements. How can one show a -3DB point at 35hz and the other showing 103.6 DB all the way down to 20hz?

Also, obviously the bass response is for one speaker. Running two speakers how much more DB can you expect from 20HZ to 40HZ?

Any thoughts on the why the numbers could be so different and which "correct"?

Thanks,

-Brian

The key word is average output. Not that it hits a 103.6 db at 20hz. it's probably way down at 20hz. Look at how fast the 8080 rolled off from 35hz to 33hz. I can only imagine how much lower it is at the 28-30hz.

They also measured the speakers at different distances and it looks like a different testing methodolgy.

A few other things to keep in mind. While towers with built in subs can be cool and look impressive. They can limit your ability to get the best performance by not being able to move the subs around to get the best response. This can have a HUGE affect on bass quality.

On another note Def Tech tends to exaggerate their specs to make their products looks better than they are. They make good speakers just take there specs with a grain of salt if the seem to good to be true.

 

[Audioholics]

It is really expensive to actually have a true "full-range" speaker of good quality without sacrificing a lot elsewhere.

 

[Bghead8che]

It is really expensive to actually have a true "full-range" speaker of good quality without sacrificing a lot elsewhere.

Yes, I meant to point out the "average word". As obviously 20HZ is not the same 40HZ.

Curious though, in a "perfect" scenario how much DB does adding a second sub add? In other words if it "averages" 103 what would it "average" with two?

I once owned some Genesis 300s. They were full range in every sense of the world. -2DB at 20HZ 110DB.

-Brian

 

[AcuDefTechGuy]

Any thoughts on the why the numbers could be so different and which "correct"?

It really depends on who's doing the testing. It looks like Brent Butterworth did the measurement on the 8060ST from 2 meters out: 21 Hz to 20 kHz ±3.9 dB.

I think I can trust Brent Butterworth.

But I would trust Tom Nousane even more, especially since he has a pretty big room.

I think the bottom line is, the 8080 & 8060 both have impressive bass response. Be happy.

 

[TLS Guy]

Yes, I meant to point out the "average word". As obviously 20HZ is not the same 40HZ.

Curious though, in a "perfect" scenario how much DB does adding a second sub add? In other words if it "averages" 103 what would it "average" with two?

I once owned some Genesis 300s. They were full range in every sense of the world. -2DB at 20HZ 110DB.

-Brian

Two subs apart will add 3 db, if they are side by side 6 db.

As you were told a good full range speaker is a very expensive project. The Genesis 300 you quote is $30,000.

Generally a good full range speakers that can achieve high spl. is going to be $20,000 and up and largely up.

I'm not discouraging it, as I use true full range speakers, and I personally believe there is huge merit in that approach.

I was talking to Greg Reierson of Rareformastering, a couple of weeks ago and he will not use anything but full range speakers and will not use a sub. He uses speakers from PMC. Those speakers were $27,000 new some years ago and the current equivalent model much higher now.

So that is why slim small driver speakers and subs have become popular. Speakers size also enters into the equation.

The next issue is we live in the age of the 0.1. If you have full range speakers and want the effects of the 0.1 optimally reproduced, then you have a problem that there is no off the shelf solution for, and you have to get creative. I can assure you it is possible, somewhat but not excessively complex. My solution works well and I think it is elegant.

However you have to have speakers that are at least actively biamped.

There is no solution possible for a set of passive full range speakers.

 

[Bghead8che]

It really depends on who's doing the testing. It looks like Brent Butterworth did the measurement on the 8060ST from 2 meters out: 21 Hz to 20 kHz ±3.9 dB.

I think I can trust Brent Butterworth.

But I would trust Tom Nousane even more, especially since he has a pretty big room.

I think the bottom line is, the 8080 & 8060 both have impressive bass response. Be happy.

The reason I am so interested in this particular aspect is I bought 4 Definitive Tech 8080s and did not budget in a sub. I was hoping 4 full range 8080STs would work. I realize a dedicated sub is required for true 20HZ extension but I figure 4 12"s would not be half bad

Hope I made the right decision.

-Brian

 

[gpost3]

It is the subwoofer placement that matters. I would personally look for 2 10's to fill up a mid sized room. 4 12's would be good for a massive room and if you have that type of money.

 

[TLS Guy]

It is the subwoofer placement that matters. I would personally look for 2 10's to fill up a mid sized room. 4 12's would be good for a massive room and if you have that type of money.

Where did you come up with that absurd formula?

Nowhere in the calculations for bass extension does driver size enter into it.

Basically the lowest usable bass extension is set by driver Fs.

Spl. will be determined by driver xmax, efficiency, power handling and the loading of the driver.

Take a look at what this 8" driver will do.

 

[gpost3]

You are right. I personally liked the xmax and Fs on tang band 6.5 inch subwoofer. They were crazy for their size:

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-832

But then again, I was speaking very generally. Maybe I should be more careful.

 

[AcuDefTechGuy]

The reason I am so interested in this particular aspect is I bought 4 Definitive Tech 8080s and did not budget in a sub. I was hoping 4 full range 8080STs would work. I realize a dedicated sub is required for true 20HZ extension but I figure 4 12"s would not be half bad

Hope I made the right decision.

-Brian

Brian, you are not going to be disappointed with four DT8080 internal subs. If the 8060 can go down to 21Hz @ -3dB @ 2 meters, I'm sure the 8080 can go down to 20Hz @ -3dB @ 2 meters. You don't need any more subs.

I was using 2 Def Tech BP7000SC towers full range without external subs and it produced tremendous subwoofer bass to my full satisfaction.

Home Theater Magazine (& others) seems kind of hit-or-miss for the past few years when it comes to measurements of both speakers and electronics. I assume it's because they keep on using different personnels/rooms for measurements.

You will be happy with the bass performance of four DT 8080ST.

Unfortunately, you may one day be hit with the upgraditis bug, as we are all susceptible or vulnerable and want an external subwoofer.

But hopefully you will be able to resist the temptation and hold your ground. Four 8080s is plenty of good bass. Be happy.

 

[Bghead8che]

If the 8060 can go down to 21Hz @ -3dB @ 2 meters, I'm sure the 8080 can go down to 20Hz @ -3dB @ 2 meters.

Where did you get those measurments? No one has tested the 8060 down to 21 at -3DB that I am aware of?

Thanks,

-Brian

 

[AcuDefTechGuy]

Where did you get those measurments? No one has tested the 8060 down to 21 at -3DB that I am aware of?

Thanks,

-Brian

The bottom -3dB point is @ 21Hz. The -3.9dB point is @ 300Hz. Except for this 300Hz point, the rest of the 21Hz - 20KHz is +/- 3dB.

8060ST from S&V:

The subwoofer section of the BP-8060ST Low bass output (40-63 Hz) averages 110.5 dB and ultra-low bass (20-31.5 Hz) output averages 103.6 dB.

The RED line is the 8060ST:

Basically, any speaker that can output 100dB+ from 20Hz-30Hz is a full-range speaker.

 

[Bghead8che]

The bottom -3dB point is @ 21Hz. The -3.9dB point is @ 300Hz. Except for this 300Hz point, the rest of the 21Hz - 20KHz is +/- 3dB.

8060ST from S&V:

The subwoofer section of the BP-8060ST Low bass output (40-63 Hz) averages 110.5 dB and ultra-low bass (20-31.5 Hz) output averages 103.6 dB.

The RED line is the 8060ST:

Basically, any speaker that can output 100dB+ from 20Hz-30Hz is a full-range speaker.

That's makes sense. I read the comments on that test but never bothered to look at the graph.

Did you check out the response for the blue line (the center). According to S&V the center channel has BETTER bass response down low in some cases by 2-4DB. So they are claiming the center channel goes down to 20HZ and has better response than the full size 8080ST? Yeah, I'm confused.

Yet, it gets better. The SURROUNDS have even better bass response and are only down -3DB at at 23HZ. I would say these are incorrect results.

What am I missing?

-Brian

 

[GranteedEV]

"The subwoofer section of the BP-8060ST is fairly kicking given the speaker’s compact size. Low bass output (40-63 Hz) averages 110.5 dB and ultra-low bass (20-31.5 Hz) output averages just 103.6 dB — numbers that put some midsize subwoofers to shame. It’s not distortion that limits the useful output in this case but either mechanical noise from the woofer cone or the amplifier’s internal limiter stepping in to protect the driver."

I am confused by the huge discrepancy is measurements. How can one show a -3DB point at 35hz and the other showing 103.6 DB all the way down to 20hz?

Nowhere in that description do I read "at 1M"

it's a lot easier to get big numbers at 1 ft than it is at 1M! ;P