Guess How Big My Speakers Are

Hi @herman - Yes, I can hear 20 Hz.  I have to turn up the volume a bit, I feel it a lot sooner than I hear it. It does not sound like chuffing or distortion.

It's real.  It's not as prounounced as 32 Hz, as you'd guess from the graphs but it's really there.

This was played from digitally created test tones.

15ft tall??

This discussion reminds me of a 1987 Stereophile article by Martin Colloms. Basically, it talks about how to optimize bass response through room positioning. Nothing groundbreaking, but a good reminder:

https://www.stereophile.com/content/who-stole-bass-no-one-stole-bass-page-4

@herman 

What can I say, I have measured using OmniMic and Room EQ Wizard with two different calibrated mics.  The two mics were in agreement except for the range from 20Hz to 30 Hz where UMIK was 3-5 dB down @ 20Hz  depending on exactly how I placed the mics. It then merged with the measurements with OmniMic at 30.

I even tried using two different DAC's, one direct and one via Roon.  This may not be lab quality work but I'm satisfied it's in the ballpark.

@herman but it is, and I’ve measured it. It’s not "real." It’s not the capability of the speaker so much as the resonance of the room.

I’ll try one more time and then leave you to it. I don’t care how much your room is adding to it, it is impossible you are getting the same level at 20 Hz that you are in the midband with a 6.5 inch speaker.. impossible.... your measurements are incorrect.

something is wrong with your measurements at the top end too when you turn up the midband by 10dB (red to yellow) but at 20KHz it goes up 20dB

if you play a 20 Hz tone do you hear it?

Very interesting discussion, Erik thank you for stimulating that.

On the subject of sub woofers, I had my pair turned "off" while the amplifier in one of them was being repaired and I really missed the "visceral" experience they add to the musical experience.  When the repaired amp was reinstalled, I used the DSP engine tuning and REW/miniDSP microphone setup to "tune" the subs to the room and the full-range speakers.  You've peaked my interest in seeing what REW/miniDSP reports with the sub woofers turned "off".

@james633  - Absolutely right.  No way we are getting live level performances out of these.

One thing this shows too though is that if we wanted to use a sub we absolutely have to high pass these speakers or the combination would be a hot mess.

While deep the output is only 75db in the graph so could be anything. Large speakers are needed for full range at high output. Small active speakers go super deep, just not loud without compressing. 

@herman 

I did retest using Room EQ Wizard and OmniMic.  REW measures about 5 dB lower at 20 Hz than OmniMIc.  It also shows a weird clipping at the top octaves.

While I agree 100% that you can't get loud at 20 Hz with small drivers (this is pure physics) I hope you see that my argument that rooms are complicated and we can't assume we know what's going on without measurement is worthwhile. :)

@herman but it is, and I’ve measured it. It’s not "real." It’s not the capability of the speaker so much as the resonance of the room.

Rooms can add 20 dB or more in a node, so this is totally possible. However, it is very much range limited. :)

From my new blog entry, you can see that compression eventually must set in...

Here you can see the output at 60, 70 and 80 dB is fine, only when we get to 90 dB is the output compressed.

it is impossible that you are actually getting as much output at 20Hz as you are in the midband.

@herman In an anechoic room you’d be correct. The room however bedevils those expectations, and that’s the point of the posting. 

I'm going to stick with my initial response. I don't care what kind of room you are in, .. you are not  really getting a strong 20 Hz out of those speakers

I guessed the closest. SF Grand Piano uses 6.5" woofs

@erik_squires , different mike places and volumes would be interesting in themselves, but the averages would be an education. ;)

Have a pleasant Xmas.

Your what?

At some point over the holidays I'll take measurements at different volumes, I am pretty sure that we won't be able to maintain the bass output, so it will be fun to see how it cuts out as the power goes up.

what do you account the two large dips at 150 and lesser at 250 Hz in your room? I’m guessing you used a white noise sweep as your source tone?

That and the peak at 30 Hz is all room/speaker/microphone location related.  Some of this would probably get smoothed out if I used multiple locations for the mic and averaged them out.

OmniMic uses swept sine waves, not really noise for these measurements.

it is impossible that you are actually getting as much output at 20Hz as you are in the midband.

@herman In an anechoic room you’d be correct. The room however bedevils those expectations, and that’s the point of the posting. Without these measurements I could do sooooo many things wrong in attempting to improve the quality of the bass.

it is impossible that you are actually getting as much output at 20Hz as you are in the midband.

@erik_squires what do you account the two large dips at 150 and lesser at 250 Hz in your room? I'm guessing you used a white noise sweep as your source tone?

The kit looks pretty good mate.

@erik_squires yep, I recall another post of yours.  I've got the "Lee Taylor" version. I don't have the room to keep as far from the wall but have highly dampened the ports with fill.  Had good extension with subs so room may be behaving differently.   I was getting 80 to 90 hz blooms until I added some DIY Knauf based panels.  Now working with new Raven so I have option to run 80hz HP to them.  

@erik_squires yep, I recall another post of yours.  I've got the "Lee Taylor" version. I don't have the room to keep as far from the wall but have highly dampened the ports with fill.  Had good extension with subs so room may be behaving differently.   I was getting 80 to 90 hz blooms until I added some DIY Knauf based panels.  Now working with new Raven amp so I have option to run 80hz HP to them.  

Looks like room bass node at 30hz.  

Given the flat response above 10khz, I'd say 3 way floorstanding speaker with 8 inch woofer.

What size shoes and gloves do you wear?

This will tell us how big your “speakers” are!

And l was thinking Bose 901's 

No, No, what really matters is that your speaker cables are elevated 😄

Are they 1cubic foot bookshelves? Say, Squires hrs-1..... Or something like that?

😁

I pretty much stole the cabinet from the Klang/Tong Nada if memory serves. Quite a large cabinet really.  However, I deviated in my crossover design from normal practice by NOT making measurements quasi anechoic but in-room for the bass. As a result the room gain was taken into account then. Even so, I still think I should have considered a smaller cabinet for a bit of low end punch.  Nothing I can't fix with EQ and proper placement though. 😁

@erik_squires what is the volume of your cabinets?   I too run Scanspeaks in  ported but don't have your measurement equipment to compare to my room.  Your stated dimensions are speakers / position.  What is room?

Show us something meaningful…like the waterfall…

Sir, you can't handle my waterfall plot. 😂

Show us something meaningful…like the waterfall…

Actually a good thread

Robot running FFT..…

bone crushing bass is the soul of real music…..room gain ain't enough..

as I gaze fondly at my Ampeg stack with 6x10”….

I am a Fender Jazz bass in a punk band Robot

@lucky_doggg7 

Unlike the people who can afford those speakers and a house to put them in, I actually work for a living.

Could they be Scanspeaks?

Thanks for your insight, @Rokral - Let us know when you get the gist of the thread.  Give it time and breathe, it will come to you.

Gist means meaning, or central point, by the way.

Your speakers and $10.00 will get you 2 Whoppers, an order of fries, and a medium drink at Burger King.

@alucard19

You may be a vampire, but the HSU VT15t is currently 100% on HT duty. :) I had it set up for stereo before. Back then I had no processor, used an Oppo BluRay player as my processor and ran everything through a Parasound 7.1 preamp.

Now I have a processor and a 2 channel integrated and things got a lot more complicated.

eric,

I thought one of your speakers was AN HSU sub,

Do I get a 33% correct for this answer.:-)

@djones51  That's more or less how I am setting them up with Roon.  I'm still playing with the overall tilt, but I disabled it all for the sake of this posting.

I hope all you readers understand I’m not trying to sell you on my speakers or drivers, at all because I don't think this is unique to my situation.

The point of this thread was more to discuss how much bass there can be when we include the room in the measurements, and maybe to encourage everyone to think of room acoustics first, new subwoofers second.

@pedroeb 

The measurements you see are from my couch! :)  I use OmniMic, which will automatically blend in gated high frequency with ungated low frequency.  

What does the curve look like at the listening position with the room acoustics taken into account?

@onhwy61  Compression is probably the least measured feature of speakers.  Only SoundStage regularly measured it, and I expect these speakers will have some of that.  I'll try taking new plots.

I can tell you one thing though, the Mundorf AMT's I use for the tweets DO NOT COMPRESS.  They have amazing power handling and incredibly low distortion.  The limits of excursion in the mid-woofers though will probably be a factor.

I imagine the graph would look very different at an 80-85dB level.

This right here...

They look real good >1khz I would smooth the peaks a bit <500hz with EQ. I thought they were  3 way Bookshelf with that much bass. 

@larry_sioux

Fritz tunes his speakers for more punch, with smaller cabinet sizes.  These sound a lot more laid back by comparison.  I will say he is using what I consider among the best sounding mid-woofers on earth. :-)

I was gonna guess Fritz, but now I’ll throw out Selah as a Hail Mary.  I just hope the performance graph of your investment portfolio looks different from this. 

We’ve reached the 5 guess threshold.

While I am a fan of Monitor Audio, that guess was wrong, as were all floor standers. "Large monitors" with 8" woofers was also incorrect.

Also incorrect was "long throw."

The in room response you see there is generated by a 2-way ported speaker with 6.5" mid-woofers from Scanspeak. While highly regarded by makers like Fritz, YG and Wilson, I wouldn’t classify them as particularly exotic.

The main point I wanted to make though was that, with room gain, a lot of speakers go lower than we think. Maybe not as loud as we’d like, but the output at 20 Hz is not nearly as far down. Room treatment helps make t his possible by damping down the mid/hi frequencies in the room, otherwise this response would probably go upwards.  Maybe a speaker that measures down to 40 Hz on paper is actually good enough for a lot of locations.

Would I add a sub? A question I debate a lot lately. If I did though, given how much output I have already I’d surely have to introduce a high pass filter. Adding a sub without one would be madness.

Whatever they are they need some EQ below 500hz. There's been at least 5 guesses. 

Modestly proportioned 2 1/2-way floorstander.

small