The budget 6.5 in woofers that I used to build the slot loaded OB are now back in stock at PE. $100 will get you 25 of them shipping included.
https://www.parts-express.com/6-1-2-poly-cone-midbass-woofer-4-ohm--299-609
https://www.parts-express.com/6-1-2-poly-cone-midbass-woofer-4-ohm--299-609
Both Linkwitz and JohnK use their tweeters above 7/6 kHz. They are already beaming there. This avoids the dipole dip which otherwise would be part of the mounting baffle geometry. Both have the tweeters waveguided to some degree. The SEAS tweeter with a built-in-WG, the Peerless with a waveguide in the baffle.
As a result a larger part of the 90° cancellation is coming from beaming - probably only a minor part is due to dipole cancellation. If you leave the rear tweeter off, this should affect the total high frequency energy in the room, but should not change much for the direct response.
Rudolf
As a result a larger part of the 90° cancellation is coming from beaming - probably only a minor part is due to dipole cancellation. If you leave the rear tweeter off, this should affect the total high frequency energy in the room, but should not change much for the direct response.
Rudolf
Thanks Rudolf !
The monacor coaxial unit is waveguided in the centre for the tweeter. If I decide to use it as OB I can always add a rear tweeter if more HF is needed in the room.
I wonder how much shipping to the UK would be for 25+ 6.5 d rive units
Shame...
Just crunched the numbers.. for 26 to the UK.. they want $175 for shipping.
Add 10% Outside EU tax then VAT and it comes to $360 for 26 .. or $14 per drive unit ..
£9 a drive unit is still good but not the bargain it is in the US ..
Just crunched the numbers.. for 26 to the UK.. they want $175 for shipping.
Add 10% Outside EU tax then VAT and it comes to $360 for 26 .. or $14 per drive unit ..
£9 a drive unit is still good but not the bargain it is in the US ..
If you seal the back of a slot loaded woofer and connect the back chamber through the slot, you can get a pretty efficient bandpass tapped horn like reflex. Here is an example I modeled with two Beyma 18 in woofers. This is much bigger and more than what one would use as the bottom on an OB but demonstrates another box that can have a narrow front profile for large drivers.
http://www.diyaudio.com/forums/subwoofers/119854-hornresp-444.html#post3919028
It would look something like this:
And this is the output with a HPF applied - the bandwidth actually goes up to about 200 Hz (and you can use the 280 Hz dip to coincide with the XO point) and can be EQ'd flat in DSP. 100 dB output at 2.83v. This particular design will go up to 124dB at 44 volts (xmax limited).
I think a similar thing can be done much smaller with dual 12 in woofers - also, deeper bass can be obtained with lower SPL efficiency.
http://www.diyaudio.com/forums/subwoofers/119854-hornresp-444.html#post3919028
It would look something like this:
And this is the output with a HPF applied - the bandwidth actually goes up to about 200 Hz (and you can use the 280 Hz dip to coincide with the XO point) and can be EQ'd flat in DSP. 100 dB output at 2.83v. This particular design will go up to 124dB at 44 volts (xmax limited).
I think a similar thing can be done much smaller with dual 12 in woofers - also, deeper bass can be obtained with lower SPL efficiency.
Last edited:
PRV 5MR450-NDY in OB FAST
I recently used the Cheap and FAST slot loaded OB cardboard frame to test out a new fullrange driver - the PRV 5MR450-NDY, a 5 inch pro audio driver capable of 98 dB sensitivity AND 250 watts of power handling. The details of this driver are in this thread: http://www.diyaudio.com/forums/full-range/259293-prv-5mr450-ndy-fast-applications.html This driver measures really well as it is quite smooth over the 200 Hz to 15kHz range. The measurements were done here because I needed a convenient test baffle and wanted to make sure I was not getting any box resonance effects when first evaluating a new driver. Here is a photo of the new driver in the test setup (you can see that it resembles a TC9FD on steroids):
Anyhow, the driver ended sounding really nice and has a natural rolloff that begins at 340Hz due to the baffle width of this setup. I reloaded my 6.5 in buyout woofers into the slot loaded OB woofer array on the bottom and hooked the system up to a new 2.1 TPA3116D2 amp - a Breeze Audio unit that I brought back to life. This amp has a built in XO for the subwoofer output and runs the tops fullrange. I listened to a few songs and to my surprise it sounded very good and well integrated given the random XO setting. I set up the mic and measured the response with just the slot loaded woofer array, just the 5MR450-NDY top, and combined. Lo and behold, the planets aligned, and the gods must have smiled upon me because the 340 Hz rolloff of the top in this OB PERFECTLY matches the default XO point in the amp and I got basically perfect integration of the top and bottom. Here is the measured data and note that there is no DSP applied here, no EQ, no BSC, just gain balancing between top and bottom via volume knobs. Measurement was taken on-axis at 1-meter away with volume set at typical listening levels.
So how does it sound? Very nice and I can say that this 5 inch pro audio "woofer" with a bullet proof stiff cone and suspension seems to have pretty nicely resolved highs with sufficient detail that I did not feel like I needed a super-tweeter. Here are some sound clips (in mono) so you can get an idea of what this sounds like. I have not had a chance to listen to this slot loaded OB (SLOB) in a while as the drivers were being used elsewhere, but listening to it again, it reminds me that SLOB sounds really really good - very natural presentation.
As this new driver costs $105, I guess it is no longer a cheap and FAST OB, but it is now a loud and FAST OB
I recently used the Cheap and FAST slot loaded OB cardboard frame to test out a new fullrange driver - the PRV 5MR450-NDY, a 5 inch pro audio driver capable of 98 dB sensitivity AND 250 watts of power handling. The details of this driver are in this thread: http://www.diyaudio.com/forums/full-range/259293-prv-5mr450-ndy-fast-applications.html This driver measures really well as it is quite smooth over the 200 Hz to 15kHz range. The measurements were done here because I needed a convenient test baffle and wanted to make sure I was not getting any box resonance effects when first evaluating a new driver. Here is a photo of the new driver in the test setup (you can see that it resembles a TC9FD on steroids):
Anyhow, the driver ended sounding really nice and has a natural rolloff that begins at 340Hz due to the baffle width of this setup. I reloaded my 6.5 in buyout woofers into the slot loaded OB woofer array on the bottom and hooked the system up to a new 2.1 TPA3116D2 amp - a Breeze Audio unit that I brought back to life. This amp has a built in XO for the subwoofer output and runs the tops fullrange. I listened to a few songs and to my surprise it sounded very good and well integrated given the random XO setting. I set up the mic and measured the response with just the slot loaded woofer array, just the 5MR450-NDY top, and combined. Lo and behold, the planets aligned, and the gods must have smiled upon me because the 340 Hz rolloff of the top in this OB PERFECTLY matches the default XO point in the amp and I got basically perfect integration of the top and bottom. Here is the measured data and note that there is no DSP applied here, no EQ, no BSC, just gain balancing between top and bottom via volume knobs. Measurement was taken on-axis at 1-meter away with volume set at typical listening levels.
So how does it sound? Very nice and I can say that this 5 inch pro audio "woofer" with a bullet proof stiff cone and suspension seems to have pretty nicely resolved highs with sufficient detail that I did not feel like I needed a super-tweeter. Here are some sound clips (in mono) so you can get an idea of what this sounds like. I have not had a chance to listen to this slot loaded OB (SLOB) in a while as the drivers were being used elsewhere, but listening to it again, it reminds me that SLOB sounds really really good - very natural presentation.
As this new driver costs $105, I guess it is no longer a cheap and FAST OB, but it is now a loud and FAST OB
Attachments
In the spirit of cheap (no-cost) FAST, here is a way to play with active bi-amping with equipment you already have. Just add your drivers.
http://www.diyaudio.com/forums/multi-way/261506-using-stereo-sound-card-create-mono-2-way-active-crossover.html#post4047802
http://www.diyaudio.com/forums/multi-way/261506-using-stereo-sound-card-create-mono-2-way-active-crossover.html#post4047802
Hi Kambule, are you talking about the Peerless SDS-P830657/ SDS-160F25PR01-08 woofer? Those are sold at fairly reasonable prices in Taobao shops. Haven't tried them but seriously interested in mating them with Vifa TC/TG9 for a cheap OB
By the way, since you're also from the same town - do you know any good carpenters around? I need to build some test cabs. Shall we PM? Thanks
By the way, since you're also from the same town - do you know any good carpenters around? I need to build some test cabs. Shall we PM? Thanks
Hi xrk971
I am interested in your amplifier arrangement. I have a 2*50 TPA3116 power some small two ways and recently purchased a 2*100; I'm told the PBTL mode requires less than 4ohms? How many ohms were the woofers operating at? How have you powered this set up, multiple PS's or one larger unit?
Any photos or links to a thread of your amp for this would be great.
I was running the 4R drivers 3-series and 2-parallel for 6ohms total. I made some suggestions for a PBTL in a previous post but myself, only have driven it with a regular BTL 3116 at circa 40 watts max. The drivers are quite sensitive in this mode are quite sensitive and I never really needed that much power for listening levels in my room (probably 10 to 12 watts max).
My current setup is shown here:
http://www.diyaudio.com/forums/clas...an-jing-build-noob-questions.html#post4446850
It is dual TPA3116D2 Ybdz and single miniDSP 2x4 (cost of system is about $150 including $10 advanced 2-way plugin and shipping):
I am starting to look into class AB LM3886 amps right now, but present system in practice is still 3116d2's or TDA7498's instead of 3116's.
Hi
I was directed to your thread since I am building OB speakers myself. Just listened to your recording from more than a year ago:
The clarity from the wide range is evident over my headphones, however I would have used a subwoofer in there to complete the range of sound. Maybe some equalization, I prefer to emphasize the highs - cymbals for example.
I was directed to your thread since I am building OB speakers myself. Just listened to your recording from more than a year ago:
The clarity from the wide range is evident over my headphones, however I would have used a subwoofer in there to complete the range of sound. Maybe some equalization, I prefer to emphasize the highs - cymbals for example.