Floorstanders either side of TV in room corner?

[alexclaber]

Seems a bit of a waste to use the ER18RNX in a smaller sealed cab and thus miss out on their deep bass extension and fairly high Vd in a large ported cab. Have noticed that if I increase your cab depth to 11" I can knock 5" off the height, which is good from the WAF front, and much cheaper than a smaller floorstander plus an active sub.

As these speakers will be relatively closely spaced - just under 4' apart - will they couple in the frequencies below ~75Hz (1/4 wavelength = 4' ish) and produce an extra 3dB of sensitivity down there?

Alex

 

[Jay_WJ]

Seems a bit of a waste to use the ER18RNX in a smaller sealed cab and thus miss out on their deep bass extension and fairly high Vd in a large ported cab. Have noticed that if I increase your cab depth to 11" I can knock 5" off the height, which is good from the WAF front, and much cheaper than a smaller floorstander plus an active sub.

It is true that the ER18RNX was designed optimally for use in a vented alignment. But note that if you want very high SPL for HT, even the MTM can't handle the bass duty without a sub. It depends on a person, though. I for one don't listen very loud and don't need too much bass even for movie.

The only reason why I suggested a 44" high cabinet is that the design is MTM. You can shorten it if you're okay with lower listening height.

As these speakers will be relatively closely spaced - just under 4' apart - will they couple in the frequencies below ~75Hz (1/4 wavelength = 4' ish) and produce an extra 3dB of sensitivity down there?

The best way of finding your best tonal balance is to experiment with BSC and port tuning yourself. My suggestion is first trying my default xover and bass tuning. The best scenario is, you're satisfied and stop there. If not, you can adjust BSC and/or port length based on your listening feedback.

 

[alexclaber]

It is true that the ER18RNX was designed optimally for use in a vented alignment. But note that if you want very high SPL for HT, even the MTM can't handle the bass duty without a sub. It depends on a person, though. I for one don't listen very loud and don't need too much bass even for movie.

I think this will be plenty of bass output - I doubt the woofers in my current speakers have more than 3mm of Xmax, they're only 5.5" diameter, and there's only one in each speaker, plus the tuning frequency is somewhere in the 55Hz region, so a pair of 6mm Xmax 7" woofers per speaker should be quite an improvement!

The only reason why I suggested a 44" high cabinet is that the design is MTM. You can shorten it if you're okay with lower listening height.

That makes sense - our sofas and TV are rather low slung so a 39" height will be less imposing and still leave our ears on-axis to the tweeter.

The best way of finding your best tonal balance is to experiment with BSC and port tuning yourself. My suggestion is first trying my default xover and bass tuning. The best scenario is, you're satisfied and stop there. If not, you can adjust BSC and/or port length based on your listening feedback.

Will do! I have a new bass cab to build first (Eminence 3015LF and Eighteen Sound 6ND410, biamped beast) but look forward to reporting back with results. Thanks tons for the help!

Oh, one other thing - just messing around modelling the ER18RNX in WinISD Pro and although I'm very impressed at the power handling below 100Hz (most hi-fi midbass drivers seem to struggle with 10W let alone half RMS power) this does mean that the port air speeds are rather high with a mere 2" port. Then again, listening to music there isn't a whole lot going on below 40Hz and during film explosions etc does a bit of chuffing really matter?!

Alex

 

[Jay_WJ]

Oh, one other thing - just messing around modelling the ER18RNX in WinISD Pro and although I'm very impressed at the power handling below 100Hz (most hi-fi midbass drivers seem to struggle with 10W let alone half RMS power) this does mean that the port air speeds are rather high with a mere 2" port. Then again, listening to music there isn't a whole lot going on below 40Hz and during film explosions etc does a bit of chuffing really matter?!

Ideally, two woofers with 6 mm xmax will need a 3" diameter tube. But in practice, many people go with 2" due to required port length for low tuning.

You're right. You won't notice port chuffing in music unless you listen to a particular type of music very loudly---you know what I mean During film, explosions etc are noise, anyway.

Even speakers selling at $8000 use a port less than 2" dia---see:
http://www.teac.com/esoteric/MG-20.html

 

[Mike C]

Hi Alex, Jay in particular;

Alex, I can confirm that the ER18RNX / 27TDFC MTM speaker is a real peach, and if it fits your general requirements and size constraints, I strongly suggest you build this one.
What's more I'm in the UK and will most gladly let you have a listen if you can get over to Essex some time.

I've posted before about the dynamics, bass, resolution; all of which are very good indeed. In the last few weeks the speakers have run in, giving that excellent combination of detail and resolution with smoothness that I've only heard from top quality gear. Female vocals are now exceptionally good; clarity and transparency are superb, but without harshness. Very natural sounding; it all adds up to a persuasive and emotional result.

Classical music comes over very well indeed, with dynamics, bass and tonality all superb. They have the dynamics, rhythmic ability and quantity and quality of bass to make rock music sound good (with 6.5 watts!) though I don't listen to much of this. Fairport's Nottamun Town is bloody amazing! The power and speed of it .... wow.
And the delicious delicacy of intimate female vocals; these speakers do the lot.

Email me for more info, especially if you can come over for a listen. Or just build them.

Thanks Jay for your help. I have some small mods to the crossover to try (still) but these things are so good I'm afraid to touch *anything*!

Regards
Mike