[audio1246]

Does anyone have the frequency response curves (graph) of HT2-TLs? I would be interested in taking a look.

Thanks,
A

[jsalk]

Does anyone have the frequency response curves (graph) of HT2-TLs? I would be interested in taking a look.

Thanks,
A

Here you are...





- Jim

[audio1246]

Thanks Jim!

[neekomax]

Wow, if I'm reading that right, that's crazy flat! On-axis, I presume? Just curious, why do the FR graphs I see never seem to show below 200 Hz or so?

[Art_Chicago]

Wow, if I'm reading that right, that's crazy flat! On-axis, I presume? Just curious, why do the FR graphs I see never seem to show below 200 Hz or so?

because the FR below 200 Hz heavily depends on the room response (according to Jim and Dennis)

[neekomax]

because the FR below 200 Hz heavily depends on the room response (according to Jim and Dennis)

Yeah, but these aren't in-room measurements right? So wouldn't it be a helpful baseline at least?

[audio1246]

How is the response at 30° and 60° off axis?  Also aren't the HT2-TLs rated at 88db? The graph shows a slightly lower sensitivity - unless I am missing something.

[Big Red Machine]

Yeah, but these aren't in-room measurements right? So wouldn't it be a helpful baseline at least?

No. Measuring his room is no indicator of what your room will do to the response.

[Big Red Machine]

Wow, if I'm reading that right, that's crazy flat! On-axis, I presume? Just curious, why do the FR graphs I see never seem to show below 200 Hz or so?

On-axis, done right there in the shop.  It takes about 3 seconds and this is what you get.  Cannot take into account his room or your room - it tells you what the drivers have been integrated to do optimally.  Mic is just a few feet out in front of the speaker.

[jsalk]

This measurement was taken on axis at 1 meter at the tweeter level.  Any measurement taken like this will only be good down to about 200Hz.  Below that, the length of the measurement time window required will begin to show room-related interactions as well.  So this type of measurement is not accurate below about 200Hz.

That is not to say that the areas below are this are not important. 

But keep in mind that it is basically the cabinet and cabinet tuning that determine the response below this area (not the crossover in most cases).  And the good thing is that you can model this bass response and roll-off with a fairly high degree of accuracy.  If the cabinet volume is correct and the tuning is correct, you will see a smooth response that rolls off fairly sharply near the F3 of the design (lower -3db down-point of the FR).  This is quite reliable and can be determined even before you actually build a cabinet.

Knowing that, an FR plot like this, coupled with an accurate F3, will provide a pretty accurate picture of a speaker's performance where frequency response is concerned.

- Jim

[DMurphy]

How is the response at 30° and 60° off axis?  Also aren't the HT2-TLs rated at 88db? The graph shows a slightly lower sensitivity - unless I am missing something.

Hi.   You can't read a sensitivity figure off of a Praxis plot unless you program Praxis to do that.   A standard measurement like this will vary widely among Praxis setups in terms of the absolute dB level shown.  It depends on how Praxis is calibrated and on the input signal.   For example, here's my simulation of the HT2RAAL, based on my measurements of the individual drivers run through the final crossover design.  The reference distance is one meter.  The absolute dB readout is only about 78 dB on my Praxis.




As for the response below 200 Hz, on your standard anechoic measurement, you won't get anything because the measuring window is too brief to capture the longer wave lengths with any precision.  The pressure wave from a lower frequency will arrive after the measurement is over.  However, Praxis has a feature that starts lengthening the measurement window below about 250 Hz.    This gives you sime idea of the bass response, but it's the response as shaped by room nodes, and also by floor bounce from the woofers.  At a frequency of around 120 Hz, the output from a woofer will bounce off of the floor and return out of phase, causing a big cancellation dip.  This happens on virtually every loudspeaker, unless the woofer is mounted practically next to the floor (which can cause other problems).  The result is a generally alarming series of peaks and dips, generally culminating in a big bass room peak in the 60-70 Hz area.   I'm not going to show you that response for ther HT2RAAL because it's likely to be misinterpreted.  But here's the relevant plot for one of my own designs that I did as a one-off  for a friend.  It looks a little funky down there, but that's just how real speakers measure in a room.



 Sorry-I didn't save any off-axis measurements of the HT2RAAL, but nothing weird happens off axis.   The output around 2 kHz does do down a little, as you would expect from a 7" woofer at the top of its passband, but the response is still quite smooth on out to 60 degrees off axis.

[DMurphy]

Sorry--I inserted the predicted response for the HT2TL taken at listening distance of 3.5 meters, not 1 meter, so the dB level is lower than I stated.   I tried to edit it, but couldn't find an upload image function in edit mode.

[audio1246]

Thanks Dennis!