Need Help with Frugal Horn Rear Deflector/Sub - how to power and what driver to use?

[tlarwa]

I am building the rear deflectors in the attached plans to augment the bass of my FH3 speakers:

Frugel Horn v1 Maps 130307

As you can see, they are a fairly small (~.6 cu.ft.) sealed enclosure.

I have 2 questions:
Can you recommend a fairly inexpensive driver that would work well in this enclosure (I think the biggest that'll fit is a 7") and

What's the best way to power them? I am running these in a 2-channel analog audio only system, with a turntable as the only source. The amp is an MP-301 Mk2 (tube integrated) and the phono pre is a Parks Audio Budgie tube unit. My plan was to use a plate amp for each sub, but I'm not sure how to route the signal from the source. Any suggestions are appreciated!

Tom

[Octavia]

The rear deflector could easily be extended in height to match the frugel horn (possibly even taller if you wish). If you extend the height to give a .88 cubic ft volume then subwoofer like the 6.5" Tang Band W6-1139SI or W6-1139SIF would fit nicely into the deflector and with 11 inch by 2 inch port give you an enclosure tuned to 30Hz.

[planet10]

The deflector can be any height you want, it should be at least as tall as the FH3 (including any stands or outriggers) themselves. The volume can be further increased by increasing width and depth.

The FH1 delector has a hard to do angle specifically for the FH1 terminus. You can change to 45 degrees for ease of construction.

We used SDX7 because we have lots of them (and they are a REALLY nice driver)

What is the high frequency extension of the TB, to get a good blend you want smooth extended top (even if firing into the wall).

If you do not have the ability to separate the pre & the power amp in your integrated amp, by far the easiest way to connect is what i call REL-style... no high pass on the FH3 and dial in the woofer to fill in below. This is easy and can be done by running cables from the mains speaker to the plate amp. Downside is no relief of the FR at the bottom so it is still subject to the stresses of producing bass. An upside is that the output from the tube amp reduces differences in voicing between tube amp & plate amp.

Often with current generation integrated amps, what we really have is a power amp with volume control and selector added, so there is no preamp to get at. At that point you either go REL-style or add a pre-am to your project list (and go REL-style until you are finished)

If you have a pre-amp, you want to use a passive line level High Pass and either the XO in the plate amp or a PLL low pass and pretend the filters in the plate amp don't exist (turn them to the highest XO point available or bypass). With the last you can also just use a regular amp -- a cheap integrated or receiver or a chip amp can be a fine starter amp for woofer duties.

I use all 3 techniques, currently i have a single sealed SDX7 with Foster plate amp, REL-styled to a set of solid cedar uFonkenSET (think hi-end computer speaker being used as mains in my main room).

dave

[tlarwa]

Dave,

Can you please further explain how exactly to hook up the integrated amp, plate amp subwoofer and main speaker in the REL-style system you describe below? I'm not following (sorry). I understand that the FH3 would be running full range, and that the sub would use the x-over in the plate amp to cut out the high frequencies. What I don't get is exactly how the speakers would be wired to the amps.

Tom

If you do not have the ability to separate the pre & the power amp in your integrated amp, by far the easiest way to connect is what i call REL-style... no high pass on the FH3 and dial in the woofer to fill in below. This is easy and can be done by running cables from the mains speaker to the plate amp. Downside is no relief of the FR at the bottom so it is still subject to the stresses of producing bass. An upside is that the output from the tube amp reduces differences in voicing between tube amp & plate amp.

[planet10]

You run another set of speaker cables, either from the amp, or from the main speakers, to the speaker level in of the plate amp.

dave

[chrisb]

in other words, the high level input of the plate amp is running in parallel with the speakers - since the input impedance of the amp will be very high, the effect of the parallel load on the amplifier is negligible

if you had an integrated amp or receiver with multiple speaker outputs, you could just as easily connect the plate amp's high level inputs to one of those - it would even let you turn the sub(s) off if you liked

[sreten]

Hi,

FWIW : run normal speaker cable to the speaker terminals and
then just about any sort of bell wire from the terminals to the
speaker inputs of the plate amp as it will draw little current.

rgds, sreten.