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Measurements - Tannoy Stirling HE

You could do with a helmholtz resonator to cure that hump under 200hz, maybe more than one..
 
Hoopsontoast said:
Waterfall, Decay and Spectogram plots (Right Speaker at Listening Position)


Tannoy @ Listening (R) Decay by RSdesignUK, on Flickr


Tannoy @ Listening (R) Waterfall by RSdesignUK, on Flickr


Tannoy @ Listening (R) Spectogram by RSdesignUK, on Flickr
Click to expand...

Hoops

Can you repost the waterfall with it "pulled back" so it shows the decay more clearly. You'll probably see a long tail around 45hz ish.

I have two issues with the Gil products you link to. The pictures on the website just look like smallish foam or absorb ant material blocks. This is not going to do diddly at low frequencies as the wavelengths are too long. So if they are genuinely effective (they may be I don't have any experience of them) then I would like to know how they work. ;)

The graphs you posted earlier showed the product to have a generally broadband absorption. This won't solve the real problem. The room resonances create huge decay times at certain frequencies which create the boom or "one note ness". This will be shown in the waterfall plot. To combat this you need a tuned solution - right frequencies (there will be more than one resonant frequency), right Q and right attenuation.

The only realistic solution in most domestic environments is electronic room eq.


Edit
I was being dim and you see the decay in the spectrogram as well, but I find the waterfall more clear. Note the very long decay at 42 hz, 57hz, 66ha etc etc
 
BE718 said:
Hoops

Can you repost the waterfall with it "pulled back" so it shows the decay more clearly. You'll probably see a long tail around 45hz ish.

I have two issues with the Gil products you link to. The pictures on the website just look like smallish foam or absorb ant material blocks. This is not going to do diddly at low frequencies as the wavelengths are too long. So if they are genuinely effective (they may be I don't have any experience of them) then I would like to know how they work. ;)

The graphs you posted earlier showed the product to have a generally broadband absorption. This won't solve the real problem. The room resonances create huge decay times at certain frequencies which create the boom or "one note ness". This will be shown in the waterfall plot. To combat this you need a tuned solution - right frequencies (there will be more than one resonant frequency), right Q and right attenuation.

The only realistic solution in most domestic environments is electronic room eq.


Edit
I was being dim and you see the decay in the spectrogram as well, but I find the waterfall more clear. Note the very long decay at 42 hz, 57hz, 66ha etc etc
Click to expand...

I have been offered a loan of a Antimode DSP unit, so will see how I get on with that!

The GIK products certainly have a great reputation, I would be looking at the limited range models which are designed for more absorption in the 80-160Hz range.
 
Definitely try out the antimode. Just make sure you don't try to go for a completely flat response, it will sound bass light/bright.

I remain quite unconvinced about the Gik products ability to deal with low frequencies in any meaningful way. There may be subtle broadband attenuation but no real effect on those critical narrowband resonances and more importantly their decay.

The beauty is you have the ability to measure and see if they work. So if you get some panels do so on the basis that you can measure the differences (and no 1dB isn't a meaningful change) or you will have your money back :)

Other interesting products, Dirac, a free trial is available
http://www.dirac.se/en/solutions/home-audio/dirac-live/overview.aspx

And mini dsp products
http://www.minidsp.com/products/dirac-series/product-line-summary
 
Hoops you are welcome to borrow a MiniDSP 2x4 unit, you just need to download the most suitable plug in, that will allow you to EQ the FR, or as Be( above) suggests try the free Dirac trial.
Keith.
 
Purite Audio said:
Hoops you are welcome to borrow a MiniDSP 2x4 unit, you just need to download the most suitable plug in, that will allow you to EQ the FR, or as Be( above) suggests try the free Dirac trial.
Keith.
Click to expand...

Hi Keith,
Thanks for the offer, I will give the Antimode a go first. I already have the software as I have had a 2x4 MiniDSP unit before. :)
 
I like parametric EQ in JRiver. It is superbly flexible and very transparent. Killing the bass emphasis would be quite easy.

TBH it is a Tannoy Prestige it is supposed to sound bass heavy and the sort of response I see is pretty much exactly what I expected having heard other models in the range.

When you mess with this stuff for a while you start to get good as guessing speaker responses. Not exactly of course but gist of a response in your head.
 
Fascinating thread. I'd not even noticed the REW distortion plots before, that's really interesting! FWIW my speakers are showing far less distortion; the Klipsch and Tannoys both under 1% and up to 3% with one JR149 measurement (that being interesting as the other one is 1.1%, both measured on the same stand (I've no idea why they'd be different, but 2nd harmonic seems to be the issue there - I wonder if the metal grille of one was resonating a little?). The big speaker measurements were both driven and measured from the listening seat.

I really need to learn REW and this whole subject - I'm sure there is much of use here, it's just a matter of knowing exactly what to look for and how to act on the results. I'm still not really sure how to read waterfalls, spectrograms etc.
 
Tony L said:
Fascinating thread. I'd not even noticed the REW distortion plots before, that's really interesting! FWIW my speakers are showing far less distortion; the Klipsch and Tannoys both under 1% and up to 3% with one JR149 measurement (that being interesting as the other one is 1.1%, both measured on the same stand (I've no idea why they'd be different, but 2nd harmonic seems to be the issue there - I wonder if the metal grille of one was resonating a little?). The big speaker measurements were both driven and measured from the listening seat.

I really need to learn REW and this whole subject - I'm sure there is much of use here, it's just a matter of knowing exactly what to look for and how to act on the results. I'm still not really sure how to read waterfalls, spectrograms etc.
Click to expand...

With the distortion, I did it again at a higher level and the distortion levels were around the same 20-30dB range but the speaker level was higher.
It was peaking at around 0.25% THD around 100Hz If I am reading it correctly. It goes up to around 3% below down to around 30Hz.

It really depends on which frequency you select, unless there is a standard? And I guess picking a point in a dip that is caused by the room

Here again with the cursor on 40Hz:


Tannoy @ Listening (R) Distortion by RSdesignUK, on Flickr
 
Ah, that looks far more like what I'm getting. Your first graph upthread confused me as it gave the impression of >50% THD, which would probably sound like a fuzz box! I don't understand enough about REW to know what settings would show that. My measurements have all been pretty low, around 68-75db or so.
 
Tony L said:
Ah, that looks far more like what I'm getting. Your first graph upthread confused me as it gave the impression of >50% THD, which would probably sound like a fuzz box! I don't understand enough about REW to know what settings would show that. My measurements have all been pretty low, around 68-75db or so.
Click to expand...

Its because the numbers are taken from where the cursor was when I exported the image, probably down at 20Hz or something.
 
Hoopsontoast said:
With the distortion, I did it again at a higher level and the distortion levels were around the same 20-30dB range but the speaker level was higher.
It was peaking at around 0.25% THD around 100Hz If I am reading it correctly. It goes up to around 3% below down to around 30Hz.

It really depends on which frequency you select, unless there is a standard? And I guess picking a point in a dip that is caused by the room

Here again with the cursor on 40Hz:


Tannoy @ Listening (R) Distortion by RSdesignUK, on Flickr
Click to expand...


That's more like it!

If you want to cure the bass hump using traditional passive treatment means, the only sure fired way is with large bass absorbers, tube traps or floor to ceiling 400 to 500mm thick foam wedges at the corners. Not very much WAF in that and can get very expensive. Digital DSP looks more attractive in this instance. The bass lift by the way, is as User211 suggests, very typical of the Tannoy prestige line. The vented design for that driver in a relatively small volume does tend to produce a bass hump in response. The other way of curing this would involve (tricky but possible) extending the vent effective depth or narrowing the vent for a similar result (ie trying for EBS type tuning to lower the hump). You could experiment by varying the vent width using masking tape and stiff card as a trial. Nothing to lose by having a crack anyway and could save you a fortune on more expensive means of EQ? Then there's stuffing the vents (not too tightly) with an inch or so of acoustic foam to achieve a semi-aperiodic response which will modify woofer impedance and acoustic output.
 
Pac1 said:
That's more like it!

If you want to cure the bass hump using traditional passive treatment means, the only sure fired way is with large bass absorbers, tube traps or floor to ceiling 400 to 500mm thick foam wedges at the corners. Not very much WAF in that and can get very expensive. Digital DSP looks more attractive in this instance. The bass lift by the way, is as User211 suggests, very typical of the Tannoy prestige line. The vented design for that driver in a relatively small volume does tend to produce a bass hump in response. The other way of curing this would involve (tricky but possible) extending the vent effective depth or narrowing the vent for a similar result (ie trying for EBS type tuning to lower the hump). You could experiment by varying the vent width using masking tape and stiff card as a trial. Nothing to lose by having a crack anyway and could save you a fortune on more expensive means of EQ? Then there's stuffing the vents (not too tightly) with an inch or so of acoustic foam to achieve a semi-aperiodic response which will modify woofer impedance and acoustic output.
Click to expand...

Yes, its obvious (I was doing similar stuffing the end of the R9s TL Line) but it had not occured to me to try it on these.
The 'Ports' on the Stirlings are very odd, tall and thin but not very deep, more like a leaky box rather than a normal vented/ported box.

I had assumed, having not seen one up close, it would be more like an Onken style enclosure (below) with long and deep ports up the side of the speaker.

onken_enclosure_for38cm_driver.jpg
 
They're not very deep but are still a conventional vented design (same result as using a more typical port), so making them slightly narrower (say 10% at a time then having a listen) or trying some loose foam stuffing should have the desired effect. Worth a try? If you take the cabinet volume and tuning point and calculate the vent depth size using the width/height of your vents, it should tally closely with what you have. You can also use something like WinISD freeware, enter your driver T-S parameters (if known) and that'll work. Experimentation is fine and wont involve the maths! You only need to be careful not to have the tuning coincide with the free air resonance point of the driver as that isn't recommended for the health of the drive unit.
 
I haven't read all this thread but I see no mention of measuring both speakers simultaneously. You need to measure both at the same time to get an idea of what is happening in the bass because the speakers interact in this frequency range.
 
Playing around with the Antimode (thanks to Mark off HFWW).

Its certainly helped but not a 100% soloution, so I have experimented with some stuffing of the ports (half and full).
Tenson, measurements below at listening position, and both speakers together.


Tannoy @ Listening (R + L) with and without Antimode + With and Stuffing by RSdesignUK, on Flickr

Light Blue - Without Antimode and no Stuffing
Navy Blue - With Antimode and no Stuffing
Red - Without Antimode and full Stuffing
Orange - With Antimode and full Stuffing

And a nice looking linear graph now (no correction above 500Hz from the Antimode) and with -3dB on the Speakers, with ~15 Degrees Toe In.

Decay, RT60 and Spectrograph plots all are much improved, thats without any stands as well.

Tannoy @ Listening (R + L) with Antimode + Stuffing Distortion by RSdesignUK, on Flickr

I am not going to make any subjective comments as thats with the Antimode running as Pre-Amp and T-Amp as Power as the B60 is on its way to PMC to be looked at.

I think the Antimode is nice, functionality wise and easy 'one-touch' use. I would probably go down the MiniDSP route as its a lot cheaper and more flexible with regards to the Bass adjustment.
 
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