Am I interpreting FR curves correctly?

[6sigma]

I've been flipping between the Speaker Index and the individual reviews of many speakers. With a couple of very rare exceptions (e.g. Genelec), I think I am seeing even the best-reviewed (most expensive) speakers that begin their low-end roll offs at 90-100+/- hz and are 3dB down by 70-80hz. Am I approximately right or am I not reading the FR graphs correctly? Can any of them really get to 35 or 40hz or are we saying that EVERY speaker requires a sub to play music with content below 60 or 80 hz?

Are the vast majority of speakers THAT weak in the low end?

Thanks.

 

[YSC]

That's mostly correct when the speakers are passive, for active monitors like Genelec and Neumann while the bass roll off much later, you can see their distortion goes >5% pretty early. the reason they can go lower is that in active designs they can have the bass boosted for the driver until the distortion gets unacceptable by the company/designer. in passives you can do similar EQ to the speakers and get similar results with quality designs. but IMO in reality usage where you get boundary gain in bass regions below 100hz, the real life bass extension should go to 60-70hz at least.

 

[6sigma]

That's mostly correct when the speakers are passive, for active monitors like Genelec and Neumann while the bass roll off much later, you can see their distortion goes >5% pretty early. the reason they can go lower is that in active designs they can have the bass boosted for the driver until the distortion gets unacceptable by the company/designer. in passives you can do similar EQ to the speakers and get similar results with quality designs. but IMO in reality usage where you get boundary gain in bass regions below 100hz, the real life bass extension should go to 60-70hz at least.

Thanks. You are confirming what I thought I was seeing. Lots of discussions focus on "deep bass," "get-a-sub (or 2)," etc. While I understand those discussions, I guess I'm surprised at how high the roll off begins for an awful lot of speakers. I thought we were looking at a fair number of speakers that could get to 50hz, but the graphs don't seem to say that at all. Makes the manufacturers' spec sheets even more suspect - anechoic or not!

I appreciate the education!

 

[YSC]

Thanks. You are confirming what I thought I was seeing. Lots of discussions focus on "deep bass," "get-a-sub (or 2)," etc. While I understand those discussions, I guess I'm surprised at how high the roll off begins for an awful lot of speakers. I thought we were looking at a fair number of speakers that could get to 50hz, but the graphs don't seem to say that at all. Makes the manufacturers' spec sheets even more suspect - anechoic or not!

I appreciate the education!

I think the spec is usually something like -6db or even -10db point varying from manufacturer, for passives a lot of times they are sealed or have a port tuned for slow roll off, so the -6db point could extend quite a bit. while for the ported actives the roll off is a lot steeper

 

[6sigma]

I'm going back to look at several of the FR curves with an eye out for the -6dB low-end frequency. Thanks for this pointer. Bottom line: there just aren't many speakers that can get close to reproducing a 40-50hz signal, accept at a much lower SPL than I had realized.

 

[sweetchaos]

If you want to find out the -6db point (called LFX) of both active and passive speakers, take a look at my guides:

Active Speaker Recommendations for USA (by @sweetchaos)

I'm constantly asked which speakers to purchase...so, here you go! :D This guide is for ACTIVE speakers. For PASSIVE speakers go here. Click on the "Spoiler" buttons below to expand each section. Readme: Legend: Active Speakers (aka Studio Monitors): Bookshelf speakers (when turned 90deg)...

www.audiosciencereview.com

Passive Speaker Recommendations for USA (by @sweetchaos)

I'm constantly asked which speakers to purchase...so, here you go! :D This guide is for PASSIVE speakers. For ACTIVE speakers go here. Click on the "Spoiler" buttons below to expand each section. Readme: Legend: Never Buy This Brand: Passive Bookshelf Speakers: Passive...

www.audiosciencereview.com

 

[TurtlePaul]

Amir seems tp be tilted towards reviewing bookshelf style speakers. There arent many 6.5” woofers going below 50 hz. Also, the box sizes to tune below 45 hz get pretty big, so the “bookshelf” speakers which get the -6 dB there (Kef R3, BMR) are pretty large.

Some people overestimate how high of a pitch 40-50 hz is. That is pretty bassy, although not THX explosion or EDM low.

Plenty of speakers with 8” woofers would be happy to go down there. But many manufacturers are seeing pushback due to aesthetics because narrow speakers are more WAF friendly.

 

[6sigma]

If you want to find out the -6db point (called LFX) of both active and passive speakers, take a look at my guides:

Active Speaker Recommendations for USA (by @sweetchaos)

I'm constantly asked which speakers to purchase...so, here you go! :D This guide is for ACTIVE speakers. For PASSIVE speakers go here. Click on the "Spoiler" buttons below to expand each section. Readme: Legend: Active Speakers (aka Studio Monitors): Bookshelf speakers (when turned 90deg)...

www.audiosciencereview.com

Passive Speaker Recommendations for USA (by @sweetchaos)

I'm constantly asked which speakers to purchase...so, here you go! :D This guide is for PASSIVE speakers. For ACTIVE speakers go here. Click on the "Spoiler" buttons below to expand each section. Readme: Legend: Never Buy This Brand: Passive Bookshelf Speakers: Passive...

www.audiosciencereview.com

Wow...eye-opening. Thanks for pointing this out. I still want to study more about what it means when a speaker's low end is down 6dB below the average, measured SPL for other frequencies. That's likely quite audible. It also supports the notion that "every system needs (multiple) subs."

 

[6sigma]

Some people overestimate how high of a pitch 40-50 hz is. That is pretty bassy, although not THX explosion or EDM low.

Excellent point. I'm not wanting to reproduce sound effects or do "parlor tricks" with low frequency extension, but there is the occasional pipe organ, cannon shot or contrabassoon.

 

[Sancus]

I think I am seeing even the best-reviewed (most expensive) speakers that begin their low-end roll offs at 90-100+/- hz and are 3dB down by 70-80hz. Am I approximately right or am I not reading the FR graphs correctly? Can any of them really get to 35 or 40hz or are we saying that EVERY speaker requires a sub to play music with content below 60 or 80 hz?

You are reading anechoic data. In room the low end will be boosted by boundary effects, making the real flat point around -6dB anechoic. If your speakers are near to a wall or corner,.you will get even more than that, but will need more corrective EQ as well. There are a lot of bookshelves with -6dB at 35-50hz.

There is also a tradeoff between extension and ability to play loud. Genelec biases quite heavily towards extension which is why Amir complains they can't get loud enough a lot. They are assuming if you want to play louder you are a professional who is smart enough to use a high pass filter or buy a sub.

All that said, you need a very large speaker to play with authority below 60hz. 8-10" woofer would be the minimum IMO. And frankly you will never achieve truly high quality low bass in any room without a sub, preferably 2. That's just physics.

 

[6sigma]

There are a lot of bookshelves with -6dB at 35-50hz.

This is what I was looking for, but couldn't find. I think you've explained the differences in what the graphs show and what the speaker will do in a room with proper placement near the boundaries. Thanks.

 

[MarkWinston]

A friend of mine used to scoff at floorstanders when he saw they usually start rolling off at 40hz and say shit like "my ls50s can play down to that easily." When he actually heard a floorstander (studio 590) in my house, his jaws and underwear dropped. That was 3 or 4 years back. All he owns now are floorstanders. Lmfao!

 

[thorvat]

I've been flipping between the Speaker Index and the individual reviews of many speakers. With a couple of very rare exceptions (e.g. Genelec), I think I am seeing even the best-reviewed (most expensive) speakers that begin their low-end roll offs at 90-100+/- hz and are 3dB down by 70-80hz. Am I approximately right or am I not reading the FR graphs correctly? Can any of them really get to 35 or 40hz or are we saying that EVERY speaker requires a sub to play music with content below 60 or 80 hz?

Are the vast majority of speakers THAT weak in the low end?

Thanks.

You are reading FR correctly but you're forgetting about room gain. Such FR shape is intentional by design so that once room gain comes to play FR in the room should be approximately linear.

 

[fineMen]

As many said before, the bass response depends strongly on the room, positioning of speaker and listener anyway. High quality sound needs equalisation in virtually every case.

Between different specimen the measurements are not as comparable as one might wish for. If (A) is shy in bass, but the otherwise similar (B) is strong, the latter will of course show more distortion. One might misjudge (B) for that. And the relation distortion versus sound pressure level isn't readily predictable

bass reflex tuning shall not be higher than 45..50Hz tops, no exceptions
if any bass is desired, avoid small speakers, which is a pretty simple measurement indeed
better go for a real three-way design

 

[TurtlePaul]

You are reading FR correctly but you're forgetting about room gain. Such FR shape is intentional by design so that once room gain comes to play FR in the room should be approximately linear.

Dont oversell it. Room gain comes in well below all of the room modes in the room. If you have a speaker like the Genelec 8030c (47 hz -6 dB point) then you arent getting flat with room gain. 47 hz would be a room mode at 12 ft. You would need at least one or more room dimensions to be less than 6 ft. to flatten out a 47 hz -6 dB point. That isn’t a realistic room size.

I can see the room gain in my room when measuring with a UMIK-1. My sub has a 25 hz -6 dB point and you can see it start falling there. Then room gain flattens the chart out again at 17 hz and below. Getting bass reinforcement in the teens, or into the 20s or low 30s hz for small rooms, realistically doesnt make an impact on bookshelf speaker bass response.

 

[DVDdoug]

Except for subwoofers, speakers with 12 or 15-inch woofers are rare these days...

 

[dfuller]

A friend of mine used to scoff at floorstanders when he saw they usually start rolling off at 40hz and say shit like "my ls50s can play down to that easily." When he actually heard a floorstander (studio 590) in my house, his jaws and underwear dropped. That was 3 or 4 years back. All he owns now are floorstanders. Lmfao!

Yeah, that's because preference scores don't take dynamic handling into account. 40hz F3 is one thing, but at what volume? My KH310s are linear into the mid 30s, but they have very little headroom below about 60hz.

 

[thorvat]

Dont oversell it. Room gain comes in well below all of the room modes in the room. If you have a speaker like the Genelec 8030c (47 hz -6 dB point) then you arent getting flat with room gain. 47 hz would be a room mode at 12 ft. You would need at least one or more room dimensions to be less than 6 ft. to flatten out a 47 hz -6 dB point. That isn’t a realistic room size.

I can see the room gain in my room when measuring with a UMIK-1. My sub has a 25 hz -6 dB point and you can see it start falling there. Then room gain flattens the chart out again at 17 hz and below. Getting bass reinforcement in the teens, or into the 20s or low 30s hz for small rooms, realistically doesnt make an impact on bookshelf speaker bass response.

When you put speaker near the corner or near the wall room gain affects much broader frequency range than room mode. I belive you are mixing those two.

Sure you can't get any "teens" Hz from bookshelf speaker as you would need 30dB gain, but you do get wide LF boost from putting it on the shelf with the back behind the wall - and speaker designer counted on that.