Hi,
Inspired by WHT-acoustic model PR4 I try to calculate a bass-section for bilding an BVR-enclosure: Full range+bass-section. My bass-driver has very suitable data for BR but this kind of enclosure I am not interested in because of heavy and slow bass. Love horn bass, but dimensions for one with 12" driver would be very huge.
Below I post some simulation in hornresp.
T/S-data for Bass-driver:
Fs 33Hz
Vas 248 L
Sd 464 cm2
Qts 0,383
Mms 27,67 g
Le 0,8mH
Bl 9,6
My questions would be:
1. If the T/S parameters are well suitable for this enclosure? According to the simulated data I have Fb 36 Hz (-6dB) with group delay below 11ms.
2. Are these good data for this kind of enclosure I can get?
3. As alternative enclosure I can build e small sized BR tuned a little higher then Fs of the driver. In my case 36 Hz.
Please give some comment.
Inspired by WHT-acoustic model PR4 I try to calculate a bass-section for bilding an BVR-enclosure: Full range+bass-section. My bass-driver has very suitable data for BR but this kind of enclosure I am not interested in because of heavy and slow bass. Love horn bass, but dimensions for one with 12" driver would be very huge.
Below I post some simulation in hornresp.
T/S-data for Bass-driver:
Fs 33Hz
Vas 248 L
Sd 464 cm2
Qts 0,383
Mms 27,67 g
Le 0,8mH
Bl 9,6
My questions would be:
1. If the T/S parameters are well suitable for this enclosure? According to the simulated data I have Fb 36 Hz (-6dB) with group delay below 11ms.
2. Are these good data for this kind of enclosure I can get?
3. As alternative enclosure I can build e small sized BR tuned a little higher then Fs of the driver. In my case 36 Hz.
Please give some comment.
Attachments
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No, you inputted the T/S specs wrong [Cms, Mmd], plus the response is just for the vent, so use the 'combined response' in TOOLs to see the speaker response.
If you want a prosound 'scoop bin' type of response, then you're close, otherwise tuning it for a bit less mid-bass gain and extending the 'bump' higher in frequency will typically work better in a HIFI app.
GM
If you want a prosound 'scoop bin' type of response, then you're close, otherwise tuning it for a bit less mid-bass gain and extending the 'bump' higher in frequency will typically work better in a HIFI app.
GM
Hi GM
I cheked the T/S specs of my driver (Cms = 0,8112 mm/N and Mmd = 22,93 g), these are correct. May be I did not understand you what do you mean.
Just corrected some input par. and I think I am close to the wanted simulation. Have some doubt about a peak apr. 163 Hz very close to the main response of a bass-driver. Can I turn off this peak with a damping material without making the bass viscous?
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I don't follow. For one, I get a quite different combined response from your latest ones, though it's very close to the one I calculated initially except mine is a little larger at 143.736 L.
Yours has a better group delay down low, but that's because the 'horn' is a bit too small.
Attached is mine with what I get for your design in shadow:
GM
Yours has a better group delay down low, but that's because the 'horn' is a bit too small.
Attached is mine with what I get for your design in shadow:
GM
Attachments
A new try. BVR for bass-section (cut off 290 Hz).
The same in BR-enclosure pipe ported.
Honest I do not see any benefits of BVR.
The full range driver has average sensivity 93 db. Up 2 kHz till 12 kHz 95-96 dB.
Should I build the normal BR or BVR?
I`ve simulate also another driver with low Qts for (BLH-enclosures) which do not work in any BR-enclosures. So I `ve got an interesting result.
The same in BR-enclosure pipe ported.
Honest I do not see any benefits of BVR.
The full range driver has average sensivity 93 db. Up 2 kHz till 12 kHz 95-96 dB.
Should I build the normal BR or BVR?
I`ve simulate also another driver with low Qts for (BLH-enclosures) which do not work in any BR-enclosures. So I `ve got an interesting result.
Attachments
Hi,
Sealed is 120L for Q=0.7, classic vented 240L tuned to 33Hz.
Nothing heavy and slow about 240L tuned to 22Hz.
Quasi first order roll-off and -10dB at 20Hz.
Both sealed and vented are about -18dB at 20Hz.
rgds, sreten.
300L and 20Hz tuning, 200L and 24Hz, are also options.
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O.K. Thank you. But what about a monstrous group delay? I simulated a ported box with volume 240 L - the GD was above 22 mc. Some guy built the recomended enclosure for this bass-driver (specs. very similar to the a.m.) - appr. 145 L and was little disappointed about slow bass. I asked him, what would he do now after getting this experience - he said he would build smaller enclosure 115 Liter with higher tuning.
My intension was to find another enclosure for this driver with a faster sound. I was in hope that BVR would be the one.
Another possible problem with very low tuned enclosure is the room instalation.
May be it is also a question of our taste?
Hi,
Group delay is poorly understood and the subject of much nonsense.
It inevitably increases with good bass extension (at low frequencies).
Your friend is completely wrong IMO, lowering the port tuning is the
answer, it speeds up the bass with a leaner but deeper extension.
Low port tunings with a quasi first order roll-off match most rooms far
better than standard vented and sealed, and go a lot deeper with more
low bass powerhandling than the same sealed, but sealed is an option.
Nothing to do with taste, or opinion, if you haven't tried it.
rgds, sreten.
Group delay is poorly understood and the subject of much nonsense.
It inevitably increases with good bass extension (at low frequencies).
Your friend is completely wrong IMO, lowering the port tuning is the
answer, it speeds up the bass with a leaner but deeper extension.
Low port tunings with a quasi first order roll-off match most rooms far
better than standard vented and sealed, and go a lot deeper with more
low bass powerhandling than the same sealed, but sealed is an option.
Nothing to do with taste, or opinion, if you haven't tried it.
rgds, sreten.
I agree with sreten here. A small box will limit tuning flexibility and probably sound boomier in-room, with less extension ultimately. I've been using a 15" mid-bass in a large-ish, low-tuned box for some months now. There is a ~1st order roll-off under ~100Hz which gradually gets steeper and f3=60Hz and f10=32Hz. Matches my 10'x13' room very well. I might tune somewhat higher if I were using a subwoofer though, but not much. I had 7" isobaric hi-fi towers before that, truly flat to 40Hz and they had somewhat exagerated bass IMO. Sounded "looser" as well.
IG
IG
Two years ago I built the full range Sonido in BR-enclosure with larger volume and deeper tuned port. The sound level presure at LF was not enough that is because the FR of the full ranger was sloped from top to bottom and lower tuned bass enclosure had even less sound pressure at LF.
The sensivity of the a.m. bass driver 12" is a little higher then of the full ranger but I am not sure if it is enogh. That would be also one criterion for choice of the enclosure type and port tuning. I post below data of the both driver. They are two matched pairs but with the fine tuning I can change the sound signature of the speaker.
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