Hi All,
I have a pair of Ariel speakers, driven by a 300b amp. I am just finishing a 12B4 line preamp with first order high-pass filter at 80 Hz for the 300b's and Ariels. I bought two of the small sub amps (35W?) from Jack Hinley recently and would like to build a sub.
The Apexjr subs look promising. I see the design by David Dlugos, which describes it as push-push. On the Apexjr site, it is listed as push-pull. I assume the latter is a typo - correct?
Does this seem like a good design to try or does anyone have other suggestions. I do not want or need a humongous subwoofer - just something to fill in the bottom of my Ariels.
Thanks!
Doug Rice
I have a pair of Ariel speakers, driven by a 300b amp. I am just finishing a 12B4 line preamp with first order high-pass filter at 80 Hz for the 300b's and Ariels. I bought two of the small sub amps (35W?) from Jack Hinley recently and would like to build a sub.
The Apexjr subs look promising. I see the design by David Dlugos, which describes it as push-push. On the Apexjr site, it is listed as push-pull. I assume the latter is a typo - correct?
Does this seem like a good design to try or does anyone have other suggestions. I do not want or need a humongous subwoofer - just something to fill in the bottom of my Ariels.
Thanks!
Doug Rice
The sub amp from Jack Hidley will give you 80W @ 8ohms output and is a great buy. If needed two of those amplifiers can be bridged together for higher power output Hidley Amp FAQ doc
For the price, two of the Super8 4ohm subs from Steve at Apexjr, model very well in a 1.75ft^3 ported enclosure. You should be able to get about 107db with a F3 of 32Hz without EQ or exceeding xmax of those drivers.
If you needed a smaller enclosure( ie approx 1ft^3) you could go sealed, but the Hidley amp doesn't have bass boost capabilities so you would have to live with a much higher F3 (approx 65Hz).
The push-pull configuration will definitely help to reduce cabinet vibrations, if that is a concern of yours.
For the price, two of the Super8 4ohm subs from Steve at Apexjr, model very well in a 1.75ft^3 ported enclosure. You should be able to get about 107db with a F3 of 32Hz without EQ or exceeding xmax of those drivers.
If you needed a smaller enclosure( ie approx 1ft^3) you could go sealed, but the Hidley amp doesn't have bass boost capabilities so you would have to live with a much higher F3 (approx 65Hz).
The push-pull configuration will definitely help to reduce cabinet vibrations, if that is a concern of yours.
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follow up questions
Thank you for your reply Coke.
Looking further at the Apexjr Super8, it is 2.65 ohms. If I wire a pair in series, it would give 5.3 ohms, right?
The Hinley/NHT amp can be used for 8 or 4 ohms, BUT the Hinley amp FAQ says that when bridging two amps, they need an 8 ohm load. With a 4 ohm load, they trip the self protection. I assume this means I could only use one amp if making a dual Super8 sub, right?
I don't know much about sub drivers (obviously.) Would a DVC speaker make more sense? Or I could sell of the NHT amps. I don't think I need/want two separate sub boxes (neither would the wife.
Thanks for your help.
Doug
Thank you for your reply Coke.
Looking further at the Apexjr Super8, it is 2.65 ohms. If I wire a pair in series, it would give 5.3 ohms, right?
The Hinley/NHT amp can be used for 8 or 4 ohms, BUT the Hinley amp FAQ says that when bridging two amps, they need an 8 ohm load. With a 4 ohm load, they trip the self protection. I assume this means I could only use one amp if making a dual Super8 sub, right?
I don't know much about sub drivers (obviously.) Would a DVC speaker make more sense? Or I could sell of the NHT amps. I don't think I need/want two separate sub boxes (neither would the wife.
Thanks for your help.
Doug
Actually the Znorm of the Apexjr Super8s is 4ohms. So if you ran 2 of them in series in one cabinet they would total to a 8ohm load for the Hidley amp. Try it with one amp first, you wouldn't necessarily need to bridge the second amp unless you find that running with just one is causing clipping and/or the max output level is too low for your needs.
As I mentioned before, if you mounted 2 of those drivers and the one amp in a 1.75ft^3 enclosure with a 3" diameter flared port about 7 3/4" long you will have a nice small powerful sub with a F3 around 32Hz.
As I mentioned before, if you mounted 2 of those drivers and the one amp in a 1.75ft^3 enclosure with a 3" diameter flared port about 7 3/4" long you will have a nice small powerful sub with a F3 around 32Hz.
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Funny thing, I received two of JH's plate amps today, and two Apex Jr. subs showed up earlier in the week. Mine will go in separate boxes, one amp per driver. Opposed drivers in one box will reduce cabinet vibration, but I think I'll gain more by being able to move the subs around the room independently to try to smooth out the overall bass response. I'll see how that works out once I get to cutting wood.
I've also worked out a tapped horn design for the Apex Jr. I might try building that just for fun. It would be interesting to compare the same driver in BR and TH designs side by side.
Bill
I've also worked out a tapped horn design for the Apex Jr. I might try building that just for fun. It would be interesting to compare the same driver in BR and TH designs side by side.
Bill
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