Hi guys,
Time for me to focus on the low frequencies.
I am assuming that I am not getting good low-mid range not because of equalization and the room, but because the 18inc woofer is not well suited for 300-500 hz area. So if I equalize it it seems to sound louder, but not clean or well (Open baffle U-frame). This is my guess.
From ignorance and because I have seen lots of horn projects with Bass Reflex enclosures, I want to build a Bass Reflex prototype with a 15inches woofer. I expect to get a cleaner, punchier low mid and better integration with the horn. (it sounds anemic in that region now, but punchier at lower frequencies).
I friend of mine lend me a TAD TL-1603 for the experiment. So now I have to learn how to design a bass reflex design. I was reading about it, and it seems like based on volume and vent area and longitude you can have different bass roll-offs and that could help to change character of sound.
Do you think this is the good track?
I am going active with Minidsp and a 10W 41hz.com amplifier.
Again thanks for the advice!
Time for me to focus on the low frequencies.
I am assuming that I am not getting good low-mid range not because of equalization and the room, but because the 18inc woofer is not well suited for 300-500 hz area. So if I equalize it it seems to sound louder, but not clean or well (Open baffle U-frame). This is my guess.
From ignorance and because I have seen lots of horn projects with Bass Reflex enclosures, I want to build a Bass Reflex prototype with a 15inches woofer. I expect to get a cleaner, punchier low mid and better integration with the horn. (it sounds anemic in that region now, but punchier at lower frequencies).
I friend of mine lend me a TAD TL-1603 for the experiment. So now I have to learn how to design a bass reflex design. I was reading about it, and it seems like based on volume and vent area and longitude you can have different bass roll-offs and that could help to change character of sound.
Do you think this is the good track?
I am going active with Minidsp and a 10W 41hz.com amplifier.
Again thanks for the advice!
An externally hosted image should be here but it was not working when we last tested it.
Tad website recomends maximum low pass crossover at 900hz at 12db/oct or 18db/oct. Guess that should allow a more confortable range to find a sweeter blending between woofer and horn.
Note: I was interested in testing more modern and cheaper drivers like Beyma, but this one seems like a good one, and was available for testing how much we can get in terms of SQ.
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Carlos,
The TAD TL-1603 is a good driver for a crossover in the 500 Hz range.
All your references seem to be singular, one woofer certainly won't be a good choice for a stereo system.
Assuming you are using two TL-1603 speakers, I'd suggest around 210 liters net (for each cabinet) with tuning in the 32-36 Hz range.
Make the cabinet tall enough so the center of the HF horn and the speaker are near ear height at your listening position.
Charly,
You should also remember that the TAD drivers are really very close cousins to the JBL 2225 bass speakers. Same basic design and same person behind the design work at both companies. You just pay much more for the TAD brand name, nothing they are selling has a reasonable price tag attached!
weltersys wont steer you wrong, follow his suggestions.
You should also remember that the TAD drivers are really very close cousins to the JBL 2225 bass speakers. Same basic design and same person behind the design work at both companies. You just pay much more for the TAD brand name, nothing they are selling has a reasonable price tag attached!
weltersys wont steer you wrong, follow his suggestions.
Thanks,
This is a prototype just because the driver was available. I wouldnt mind replacing that TAD with another similar 15in driver for the final version.
I am talking in singular, just because I have been prototyping a single speaker (MONO listening).
Thas Weltersys, I will try to put all your advice and the T/S parameters in some free sofwtare to have an idea of what I get.
Best
This is a prototype just because the driver was available. I wouldnt mind replacing that TAD with another similar 15in driver for the final version.
I am talking in singular, just because I have been prototyping a single speaker (MONO listening).
Thas Weltersys, I will try to put all your advice and the T/S parameters in some free sofwtare to have an idea of what I get.
Best
Bass relex mid-bass superior
Sorry to butt in here, as I have not followed this entire thread, however, a
properly built bass-reflex enclosure housing an excellent 15" woofer designed for mid-bass will TROUNCE, as in WALK ALL OVER a whimpy open baffle attempt.
I reccomend the classic "old timers" x-over point of 500 Hz to your horn of choice. Top with a tweeter if you will, and design a TRUE subwoofer system for sub-bass (foundation of music) support.
Sit back, smile and enjoy the music.
Sorry to butt in here, as I have not followed this entire thread, however, a
properly built bass-reflex enclosure housing an excellent 15" woofer designed for mid-bass will TROUNCE, as in WALK ALL OVER a whimpy open baffle attempt.
I reccomend the classic "old timers" x-over point of 500 Hz to your horn of choice. Top with a tweeter if you will, and design a TRUE subwoofer system for sub-bass (foundation of music) support.
Sit back, smile and enjoy the music.
Scott L,
I try to stay out of the discussions of any that have to do with the OB cabinet designs as I just can't fathom why anyone would use that construction design. I guess that cancellation is something that people just want to forget about. To me unless an open back is positioned at an exact distance from the wall behind it you are just creating more problems than anything else possible. I know that most guitar players and others have no clue that the original open back guitar cabinets were intended to be placed close to the wall to act as a port just as in a BR enclosure but that information is so old that is forgotten. Horn loaded enclosures will never give you the bottom end, unless huge, and ported horn enclosures are a joke, the port can never come close enough to the output of the horn section to keep up. Leaves you BR or sealed enclosures for anything that is reasonable and fairly flat in the pass band.
I try to stay out of the discussions of any that have to do with the OB cabinet designs as I just can't fathom why anyone would use that construction design. I guess that cancellation is something that people just want to forget about. To me unless an open back is positioned at an exact distance from the wall behind it you are just creating more problems than anything else possible. I know that most guitar players and others have no clue that the original open back guitar cabinets were intended to be placed close to the wall to act as a port just as in a BR enclosure but that information is so old that is forgotten. Horn loaded enclosures will never give you the bottom end, unless huge, and ported horn enclosures are a joke, the port can never come close enough to the output of the horn section to keep up. Leaves you BR or sealed enclosures for anything that is reasonable and fairly flat in the pass band.
I use Hornresp.
It slightly exaggerates peaks and dips, but will show port resonance and velocity as well as impulse response.
OK,
I just found a simple enough Bass Reflex calculation program for my needs:
mh-audio.nl - Vented System
Calculations match exactly Weltersys suggestions (Thanks).
Entering datasheet's woofer parameters:
The program calculated an internal volume of 209 liters:
Here the software calculations:
and the simulated low end frequency response:
I just found a simple enough Bass Reflex calculation program for my needs:
mh-audio.nl - Vented System
Calculations match exactly Weltersys suggestions (Thanks).
Entering datasheet's woofer parameters:
An externally hosted image should be here but it was not working when we last tested it.
The program calculated an internal volume of 209 liters:
An externally hosted image should be here but it was not working when we last tested it.
Here the software calculations:
An externally hosted image should be here but it was not working when we last tested it.
and the simulated low end frequency response:
An externally hosted image should be here but it was not working when we last tested it.
Some ideas and questions:
1) Looks like the software had found automatically a frequency tunning equals to Fb=32.5hz. I don't have an argument at the moment to think this is right or wrong.
2)The software advices using a port diameter of a third of the woofer diameter. What is the effect of increasing or decreasing port diameter? considering that the software automatically adjusts port length. What is the benefit of using a bigger or smaller port?
I am thinkin about going out to buy PVC pipes of a similar size and the fine tune the lenght given what I could find.
3) Why to use double ports? against my intuition, resulting port lenghts are bigger. Any benefit about using two ports?
Best,
Carlos
1) Looks like the software had found automatically a frequency tunning equals to Fb=32.5hz. I don't have an argument at the moment to think this is right or wrong.
2)The software advices using a port diameter of a third of the woofer diameter. What is the effect of increasing or decreasing port diameter? considering that the software automatically adjusts port length. What is the benefit of using a bigger or smaller port?
I am thinkin about going out to buy PVC pipes of a similar size and the fine tune the lenght given what I could find.
3) Why to use double ports? against my intuition, resulting port lenghts are bigger. Any benefit about using two ports?
Best,
Carlos
I have found PVC tubes of 110mm.
That gives a port length of 570mm in a single port configuration (isn't it too short?).
Or 386mm in a dual port configuration (seems too long to be practical).
But the software advices about using ports of a diameter at least a third of the woofers diameter. That would be 133mm.
Is it ok to go with 110mm diameter and 57mm long for the port?
Best
That gives a port length of 570mm in a single port configuration (isn't it too short?).
Or 386mm in a dual port configuration (seems too long to be practical).
But the software advices about using ports of a diameter at least a third of the woofers diameter. That would be 133mm.
Is it ok to go with 110mm diameter and 57mm long for the port?
Best
Charly,
The problem with to small a port diameter is that they start to make noises that can be audible. Whistles and chuffing can result. Above about 75mm internal diameter is usually large enough at normal listening levels but there is nothing wrong with going with 100mm internal diameter. Larger than that is generally reserved for very large boxes with large diameter drivers used in high power applications. As you are finding as you increase diameter the length of the port can get very unwieldy. What you can also do with a long port length is to bend the port with a 90 degree fitting that can help a long port fit in a shallow box.
On the shape question that is something I have done many times before, I have done some very nice looking trapezoidal boxes in the past. The important point is just the internal volume of the enclosure. Don't forget to add any needed volume to make up for any internal bracing you may add as some people can add extreme amounts of bracing and then the internal volume will change significantly.
The problem with to small a port diameter is that they start to make noises that can be audible. Whistles and chuffing can result. Above about 75mm internal diameter is usually large enough at normal listening levels but there is nothing wrong with going with 100mm internal diameter. Larger than that is generally reserved for very large boxes with large diameter drivers used in high power applications. As you are finding as you increase diameter the length of the port can get very unwieldy. What you can also do with a long port length is to bend the port with a 90 degree fitting that can help a long port fit in a shallow box.
On the shape question that is something I have done many times before, I have done some very nice looking trapezoidal boxes in the past. The important point is just the internal volume of the enclosure. Don't forget to add any needed volume to make up for any internal bracing you may add as some people can add extreme amounts of bracing and then the internal volume will change significantly.
Carlos,
Since you only have ten watts powering the woofer, port "chuffing" and turbulence won't be a problem, but I'd still advise large ports in case you decide to later take advantage of the driver's potential.
Build the cabinet as a trap from the get go, don't waste time with a square/rectangular prototype which won't end up sounding exactly like what you ultimately will build.
Art
Ideally the port or ports are sized large enough so vent velocity is still low (less than around 15 meters per second) at Xmax.
A vent appropriate for a 3mm Xmax 15" would be "blown out" with a speaker capable of 15mm Xmax.
110mm sounds like it would be too small to fit the vent velocity metric, but I have not modeled your particular speaker. Of course, at only 10 watts, vent velocity will be well under 15 meters per second.
Multiple ports are often used to fit the available space, and also tend to reduce the amount of reflected (out of phase) mid-range sound coming out of the ports without needing as much fill material.
A vent appropriate for a 3mm Xmax 15" would be "blown out" with a speaker capable of 15mm Xmax.
110mm sounds like it would be too small to fit the vent velocity metric, but I have not modeled your particular speaker. Of course, at only 10 watts, vent velocity will be well under 15 meters per second.
Multiple ports are often used to fit the available space, and also tend to reduce the amount of reflected (out of phase) mid-range sound coming out of the ports without needing as much fill material.
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Hi Guys,
Been away for a while "working". Now I am testing the horn with the Bass Reflex enclosure and the TAD TL-1603.
I still need to glue the front board. No bracing and no stuffing so far.
I want to put some T-nuts for mounting the woofer, so I can glue the front board.
I quickly could realize it sounds way more integrated than before. Before it was like a hole in mid bass frequency. Now it is way more coherent and consistent.
Need to work more on this...
Been away for a while "working". Now I am testing the horn with the Bass Reflex enclosure and the TAD TL-1603.
I still need to glue the front board. No bracing and no stuffing so far.
I want to put some T-nuts for mounting the woofer, so I can glue the front board.
I quickly could realize it sounds way more integrated than before. Before it was like a hole in mid bass frequency. Now it is way more coherent and consistent.
Need to work more on this...
An externally hosted image should be here but it was not working when we last tested it.
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