Full range driver & enclosure selection help

[CrookedChris]

Hi. This is my first post so go easy. I've just gotten a good deal on an NAD7175PE receiver (75W RMS SS amp) that I need speakers for. I'm attracted to full-range configurations for cost and performance but I could use some help making a driver selection and to make sure I'm not doing something stupid.

Details of the listening space:
-Living room
-About 20ftish by 25ftish
-Listening position is about 15 ft back from short wall.
-Speaker locations in corners facing listening position
-8 ft ceiling
-Hardwood floors

Looking to spend < $300 on drivers and enclosure materials, all DIY

I really like the horn designs using the FE126e in terms of cost, size, appearance, and reviews. However, I'm concerned that the amp (75W RMS) i too big for those drivers.

The Chilli Chang uses a higher watt driver but costs more and I'm afraid I'll loose top end capability.

Maybe I just need to build/buy a different amp or consider different speaker options.

Any thoughts or advice are greatly appreciated.

[Glowbug]

Maybe CSS FR125s in BIBs?

Would work great with the corner positioning, and your power available.

[rutcho]

Originally Posted by CrookedChris

I really like the horn designs using the FE126e in terms of cost, size, appearance, and reviews. However, I'm concerned that the amp (75W RMS) i too big for those drivers.

The high power itself is not a problem. You can use the amplifier at low power, just be carefull with the volume knob.
Most often, however, the performance of the regular push-pull amplifiers is not the best at low levels. In contrast, single-ended amplifiers deliver less power, but the low-level performance is excellent.
With FE-126E used in properly designed BL horn a sensitivity of about 95-96dB/W/m can be achieved. You can reach a normal listening level with only few Watts. That's why my advice is to look for a good SE amplifier (tube or solid state - depends of your taste).

[Scottmoose]

Just to expand slightly on the above, don't worry about the maximum rated output of your amplifier; that's just the maximum. You only use what you need, and your NAD will be ticking over; the FE126E has a sensitivity of about 93dB, 1m/1w rather more than most commercial hi-fi speakers, above all in a similar price range. It's quite a sturdy little unit too -you aren't likely to fry one accidentally.

On the whole, I'd probably be inclined to change the amp in the long run, but it'll do to be going on with. As for a cabinet, if it's the 126 you want, in a room that size, I'd probably be inclined toward the Saburo double-horn. OK, I might be regarded as biased, given that I designed it, but in all honesty, it's the best I've heard that driver.

[planet10]

Power quantity should not be an issue... quality at the low power levels you would typically use with FE126e would be an issue as well as the low output impedance typical of these SS amps.

Something that might be of interst, and applicable would be the unreleased Maeshowe horn. This is suitable for the FE126e, Mark Audio CHR-70, and CSS EL70 (or any of my EnABLed versions of these drivers). You could start out with CHR-70 which would be much happier with your amplifier, and then switch to FE126e if/when you get a lower power amplifier that would be happier with FE126e.



dave

[planet10]

Originally Posted by Scottmoose

... the Saburo double-horn. OK, I might be regarded as biased, given that I designed it, but in all honesty, it's the best I've heard that driver.

So far anyway... Maeshowe is Scott's too, it just hasn't reached release.

dave

[chrisb]

Originally Posted by planet10

So far anyway... Maeshowe is Scott's too, it just hasn't reached release.

dave

or built? ... Scott?

too many designs, not enough time

To add another voice to the comments regarding amplifier power levels:

1) it is possible to blow either the FE126E or FE127E with far less than 75W (a defective amp or doing something silly with hot-jacking inputs is all it really takes), and probably far easier to do damage with a clipping low power (20W) solid state unit than tubed power of half that level. (guess how we know that?)

2) When used in a typical "BLH / BVR" etc (whether commercial or DIY), the FE126E can play plenty loud enough for most domestic environments ( i.e. less than say 600sq ft room) with as little as 20 watts, to as much power as you can muster. As best as I can recall, I've never heard them with anything bigger more than 30 watts, but for my tastes/listening levels (average well under 90dB SPL at 3 meters or less), they've sounded best on SETs of between 3.5 - 8watts. there's magic to be had there


Regarding enclosure style, your room and listening position would certainly appear to support and benefit from any of the larger, double mouth designs penned by Scott Lindgren - a more important question might be the degree of "domestic acceptance" to be included in your calculus. Some of these designs are well over 60" tall, and regardless of the quality of finishing, their size and placement requirements for optimal performance tend to dominate the visual landscape of the room.

[MJK]

If you are happy with your SS amp, I would not bother changing to a tube amp. I have been using 200 watt SS amps and full range drivers for years without any isues. Recently I picked up a tube amp because that is what everybody else in the full range community seems to use and I wanted to give a tube amp a try. My intgrated tube amp is EL84 based, 15 watts per channel, has tube rectification, and point to point wiring. It is from a well regarded manufacturer. When I substituted it into my two channel system my 17 year old son almost immediately asked "What happened to the bass?" The amp has a really nice mid range but lacks any decent deep bass output. The performance of my solid state system kills it. I am not a tube amp convert, I do not believe that any tube amp will automatically outperform a SS system.

I would invest any extra money into speakers and keep the electronics you currently are using, assuming you are happy with them. You will get more bang for the buck from upgrading speakers. You might consider an OB system since it is simple and your room is a nice size for OB. Consider the following design or some varient.

http://www.quarter-wave.com/OBs/OB_Design.pdf

You can swap the full range driver to something similar, I have modeled the Alpair 6 and CHR-70 and they also works well. As long as the full range driver has an efficieny between 88 and 90 dB (you can [ad down a higher efficiency driver) it will work with some small adjustments to the crossover. Deep powerful bass crossed over low, simple construction, that full range sound, and it meets your budget.

[planet10]

Originally Posted by MJK

My intgrated tube amp is EL84 based, 15 watts per channel, has tube rectification, and point to point wiring. It is from a well regarded manufacturer.

What amp is it Martin?

Certainly a lot of vintage tube amps, or new amps trying to mimic vintage ampos will have sloppy bass, but we have yet to find a SS amp that has the bottom of our Class A EL84 El Cheapo variant (within its limited power range) and being able to regularily borrow many from the local dealer it is not for lack of trying.

dave

[hm]

Hello Crookedchris,

the Amp is not the problem,
normally you need not more than a few watt,
look therefore the Xmax of the Fe126.

i would prefer 3 constructions
the KORNETT, ALPHORN+SCHALMEI or the new RDH20