Talking about boundary loading, cabin gain, radiation angle, Transfer function etc
Etocynned,
Many of these SPL measurements of the Car Audio builds have been taken with highly reputable meters, often at competitions... So we have a good idea of what to expect now in an average vehicle and it is more than what you see in a 1/8th space simulation by about 5 or 6 decibels (expect more for a smaller cab with stiff walls, and less for a cab that is very large, more open, or less stiff ) ..............
As far as radiation angle and boundary loading are concerned here is the progression as i understand it:
We did have an exception to this recently in Matt Kimble's vehicle... He has a 2x15" Paraflex loaded with some very nice drivers in a small car which has reinforced walls/panels, so he enjoys reduced losses and increased subbass gain ..... His system's SPL has been measured with reputable meters in the upper 150s (157db to 158 range) which is nearly 12db over 1/8th space ....
Etocynned,
Many of these SPL measurements of the Car Audio builds have been taken with highly reputable meters, often at competitions... So we have a good idea of what to expect now in an average vehicle and it is more than what you see in a 1/8th space simulation by about 5 or 6 decibels (expect more for a smaller cab with stiff walls, and less for a cab that is very large, more open, or less stiff ) ..............
As far as radiation angle and boundary loading are concerned here is the progression as i understand it:
- Full space (4pi)= is a cabinet way up in the air (no boundary loading at all) ....
- Halfspace (2pi)= is a cabinet sitting on solid flat ground in an open field ...
- Quarterspace= (1pi) is a cabinet sitting on the ground and backed up against a wall ..
- 1/8th space (.5pi)= is a cabinet tucked into a corner ..
- Then the next step in the progression is a speaker located within the cabin of a typical vehicle, and this gives us even more boundary loading than 1/8th space, adding another 5 or 6 decibels (typically and conservatively) which we can achieve by modeling it as two cabinets in parallel in 1/8th space ....
We did have an exception to this recently in Matt Kimble's vehicle... He has a 2x15" Paraflex loaded with some very nice drivers in a small car which has reinforced walls/panels, so he enjoys reduced losses and increased subbass gain ..... His system's SPL has been measured with reputable meters in the upper 150s (157db to 158 range) which is nearly 12db over 1/8th space ....
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He has videos of a few different guys "tapping out" , funny stuff but also a testament to the brutality and aggression of his 2x15" Paraflex in that small car with stiffened panels...... Not comfortable to be in there when he turns it up
..
Freddi,
A number of Super Planar tops and kickbins have been built now .... They sound different than a FLH ... People are loving the kick, impact , punch and dynamics .. ... The midbass is very lively and has a lot of presence.. It is an exciting sound......
There is a lot of project photos i need to post here, waiting to see if the image hosting code (earlier in the discussion) can be fixed, and if not I might just consider starting an entirely new discussion and migrating over some of the old posts (repairing the links in the process) ......
hey MMJ - would you trust the Partsexpress 100W/70V transformer for piezo duty? its got weight 70V 100W High Power Speaker Line Matching Transformer
Obi,
I can't speak for Freddi but i know i chose to use an image host service because i wanted the photos to be viewable by the public regardless of whether or not they have an account here, and the fact that the images will also show up on search engines is a nice bonus
Would be nice to see the forum's image manager updated to include these characteristics mentioned above and then there wouldn't be any reason to use anything else 
.. So what the heck happened??
The service i was using lost their domain and had to move everything over to another domain... The old images can be viewed with a minor modification to the posted links but unfortunately with DIYaudio we do not have the ability to go back and edit old posts in order to fix broken links...... So i am stuck until the image host i used gets their old domain back (which may never happen), or if the technical team down at DIYaudio runs a script for me to alter the links (i have discussed this with them), or it would also work if i am given access to the old posts in order to edit them
...
That's precisely why any images I share here in any posts are actually uploaded here. No worrying about broken image links. Ever
Could be worth a try
Freddi,
Looks like it could be used to drive larger arrays of parallel connected piezo horns ...... This was meant for the other discussion right? ... ..
Since my WS30 from Edcor can handle driving 3 or 4 piezos in parallel without any problems then we might assume that this low cost (Chinese?) 100w transformer could handle 10 in parallel at least............................ The transformer would be seeing a very low impedance at higher frequencies (above10khz) so at some point with enough piezos in parallel it just makes sense to switch to a different sort of network (even if it means using multiple transformers, or resorting to series-parallel wiring of the piezos, or if on a low budget just a simple cap and resistors network) ......
Freddi,
Looks like it could be used to drive larger arrays of parallel connected piezo horns ...... This was meant for the other discussion right? ... ..
Since my WS30 from Edcor can handle driving 3 or 4 piezos in parallel without any problems then we might assume that this low cost (Chinese?) 100w transformer could handle 10 in parallel at least............................ The transformer would be seeing a very low impedance at higher frequencies (above10khz) so at some point with enough piezos in parallel it just makes sense to switch to a different sort of network (even if it means using multiple transformers, or resorting to series-parallel wiring of the piezos, or if on a low budget just a simple cap and resistors network) ......
That's precisely why any images I share here in any posts are actually uploaded here. No worrying about broken image links. Ever
Brian,
If they were viewable by the public (and available to search engines ideally) then there wouldn't be any reason to use anything else ..... I think that would be great
.
No. I am surprised that the speaker lasted as long as it did. A heavy clipping 3,5 kw amp should burn the voice coil quite fast, but it lasted a few months of heavy abuse.
We are going to recone the driver. The Paraflex is a very impressive bass speaker and we will probably use it in our Volvo V50.
The paraflex hit 130 dB at 29 Hz with only 65 watts, so it is an extremly efficient design.