Best way to highest efficiency?

[el`Ol]

An affordable solution would be Schmackshorn + Faital 5" 200-2000Hz + some compression tweeter.

 

[Carlp]

Some excellent and provocative ideas here, thanks!

in your case you don´t need 105 dB,
i think even 100 dB would be extrem loud.
...
in your case a Schalmei sathorn with one aktive sub with sat crossover
for your tube would be enough in your small room

and

horns would be nice, if only for the mids and up in a 2 way with a large woofer....2 18" pro subs on Hframe or something like that is what id try myeslf, with a decent large mid horn. but thats for ultimate efficiency.

HM, wish I could read german! Maybe, as you say, I don't need extreme efficiency. Interestingly, I had thought about something similar to what you and moondog suggest. I had been wondering about a tubed amp for everything from 100-200Hz or so and up, and a solid state amp for the bottom end? Then integrate a large woofer/sub into whatever cabinet I come up with and drive that with a kind of bi-amped setup? E.g. OB with a sub? Would that end up giving me more options at potentially lower cost? Hmmm. I've been wanting to play with some tripath chips I have b/c of their apparent efficiency.

Anyway, I'm someone who doesn't need earth shaking and extremely low bass (this isn't a HT setup). Tight, well defined and controlled, yes. I built a pair of BD Pipes using 4.5" cheap drivers, and I only miss some bass response.

your amp need a poti where you can put 0,0001 Watt.

Sorry but I don't understand. What is a "poti?" The .0001 watt capability would make my life MUCH easier as I wouldn't need to work out potentially tricky topologies.

Godzilla, a BIB with the BOFU is certainly a possibility but can you give me an idea of the efficiency? The driver is something like 90dB free air (I think).

Jensen Imperials? Big, big, speakers, little tiny amp?

DECWARE Imperial Folded Horn

I've read about these. Is the scantilly clad woman smoking a cigarette an integral part of the performance? If so, not sure about the WAF. Besides, wouldn't fit in my 13x15 room. Though if I went mono...

Finally, anyone care to estimate a range of potential efficiency with 8-10" vs 12-15" drivers? Just ballpark.

Thanks again everyone.

 

[Godzilla]

>>> Godzilla, a BIB with the BOFU is certainly a possibility but can you give me an idea of the efficiency? The driver is something like 90dB free air (I think).


You would get about 90db per watt but it will go very low into the bass. If you built a BIB using the 12lta you would be at around 97db per watt.

As far as 8" drivers the BOFU (B20) is about as efficient as i've heard. But it's no longer available (at Parts Express anyway) and has been replaced with an even less expensive 8" driver by GRS. My subjective opinion of the GRS is that it's 'as efficient' but thinner sounding than the BOFU.

 

[GM]

i think your room maybe slightly small for something that big. i have a similar room, and i dont think i could tolerate anything bigger than a 8-10" speaker before the speakers were so close together i was practically listening in mono.....

??? Horns you can cram in the corners without penalty unlike simple cone/dome speakers and if built to maximize corner space, then a much bigger cab can be had before it impedes on the room/seating position too much same as a corner china cabinet.

Speaking of cabinets, it's a good way to hide a bass horn: High Efficiency Speaker Asylum

GM

 

[GM]

your room is to small,

your listening distance to low,

in your case you don´t need 105 dB,

Greets!

Hmm, too small a room, too short a listening distance is when you need to resort to headphones.

105 dB transient peak capability isn't extremely loud unless you are listening to highly compressed music, so assuming he wants to at least occasionally listen to a low/no compressed recording that can have up to 30 dB of dynamic headroom (75 dB average SPL) or louder than he would typically listen to a prime-time TV show (70-75 dB SPL), 105 dB isn't an 'overkill' recommendation.

Guess we will have to 'agree to disagree'.

GM

 

[GM]

Anyway, I'm someone who doesn't need earth shaking and extremely low bass (this isn't a HT setup). Tight, well defined and controlled, yes.

Finally, anyone care to estimate a range of potential efficiency with 8-10" vs 12-15" drivers? Just ballpark.

Though if I went mono...

Understood, short of the Imperial, Klipschorn or similar high acoustic efficiency alignment, you won't get HE below ~80 Hz without a loss of proper transient response (''tightness', etc.), i.e. the average male's lower vocal limit and as you note you can always add a sub system at a later date.

There's probably a chart somewhere, but don't recall seeing one, or if I did I didn't pay any attention to it since it has no real meaning due to being a variable based on the driver's Fs, Qes, Vas specs.

If you mean acoustic radiation impedance that's a function of a driver's volume displacement (Vd), i.e. effective cone area (Sd) times linear excursion (Xmax), then there's a formula, but would have to look it up later.

In small rooms there's lots to said for a mono system, especially if it's corner loaded with the seating position oriented to on-axis. This is a good choice for a 2.1 system with the mono 'sub' in the corner and the mains along the side walls.

These beautifully finished Altec A7-500 theater mains with an electronically EQ'd Karlson is one such system, though in a small room, one of Hm's smaller BLHs or similar might suffice for the mains depending on the driver(s) used and the 'sub' system could be any number of choices from a bass dipole 'infinite' line array to tapped pipe (TP) or horn (TH) to whatever, though a dipole array of low Fs, Qts drivers is technically your best choice short of a huge FLH.

GM

 

[hm]

Hello,
"don't understand. What is a "poti?" The .0001 watt capability"
your volume control, if you need normal householt level, 90% of the time,
normal speech 60-65 dB how much watt do you need with a 105 dB1m1W
in your case, volume control (Potentiometer) and amp won´t get it.
I don´t know an amp which work around 0,0001 Watt, may be with a Poti for 10000$ ).

 

[borispm]

Will a bipole line array work? Something like Clair Audient 16+16,
audience : loudspeakers

Use something like Aurasound NS3-194-16A as they are super cheap now:
https://www.madisound.com/store/product_info.php?cPath=45_241_282&products_id=8987

Add a horn loaded super tweeter and a powered subwoofer and off you go!

 

[Carlp]

Will a bipole line array work? Something like Clair Audient 16+16,
audience : loudspeakers

Use something like Aurasound NS3-194-16A as they are super cheap now:
https://www.madisound.com/store/prod...oducts_id=8987

The Aurasound you link to is exactly the driver that got me thinking line array was within reach. They are 82dB though, so not sure they'd get me the efficiency I seek even in a line array. The bipole/dipole idea had me intrigued, so I looked at the twitterspeak link in post 12. $0.69/driver made that seem possible too.

The trouble for me, and the reason for this post, is that I have limited experience with speakers - I've only really listened to typical multi-way boxes and single driver/fullrangers. So I hoped to get some insight into the pros and cons of different approaches to very high efficiency speakers. I'm certainly getting that.

I don´t know an amp which work around 0,0001 Watt, may be with a Poti for 10000$ ).

HM, I thought you were suggesting something that would work around micro-wattage environment. That's not my need, so no worries. As for your designs, I've been taking a look and am intrigued.

 

[tinitus]

well, we are still in fullrange forum
but maybe a 2.5way with 2x Beta8(Eminence), or similar, with some kind of tweeter
and maybe a sub

but one thing is certain with a small room, you need well balanced speakers
the more "squeaky" ones usully works better in large rooms

 

[GM]

......normal speech 60-65 dB.........

Who does critical listening at 60-65 dB for music other than some folks with headphones?

GM

 

[GM]

They are 82dB though, so not sure they'd get me the efficiency I seek even in a line array.

The problem with wide BW line arrays is that they will only sum up to a point before they collapse into discrete drivers, so system efficiency isn't all that great normally. The best line array I've auditioned was the monster McIntosh XR290 which once EQ'd wasn't very efficent, though it didn't drop over distance like a normal speaker, so was more efficient at the listening position. Great if it's a big room/long distance, otherwise not so much. Anyway, lots of good info about line arrays at Roger's site.

GM

 

[mondogenerator]

Who does critical listening at 60-65 dB for music other than some folks with headphones?

GM

hahaha...me. well max 90dB, unless im trying to cause agro with my neighbours (i live in an apartment).

listening below 70dB is a great way of judging tonal balance in a loudspeaker system, over (i think) 90dB the ears compression at LF comes in (dBC rather than dbA), then even room modes can seem less pronounced.

A high peak SPL within a sgnal of a very dynamic nature is a different thing altogether, and SPL (and power with respect to eff.) are in this case needed.

 

[borispm]

Hi Carlp,

Remember the Aurasound drivers are 16ohm instead, so by wiring them to 4 ohm, you will have an extra efficiency of 6dB/w

 

[Carlp]

Remember the Aurasound drivers are 16ohm instead, so by wiring them to 4 ohm, you will have an extra efficiency of 6dB/w

Hmmm. I hadn't thought about that. I was hoping to aim for an impedance of about 6ohm due to some nice and inexpensive output trafos by Edcor, but of course that would depend on drivers and how I wire them.

GM, I've read through most of Roger's site but thanks for the heads up. You've made me think, though, that a rated spl at 1m doesn't mimic my listening situation, which is about 10 or so feet from the speaker. That might be an advantage of a line array if in fact it somehow holds it's output with distance (I suppose I can see it isn't subject to the usual spherical radiation losses). But again, at 10' or so, maybe I wouldn't gain much via this consideration, and it's probably offset by the EQ losses. Hmmm. I can see I'd be best served by experimenting. If I only had more time and money...

Oh, and regarding multi-way, they aren't out of the question for me. I posted here in the fullrange forum b/c I thought it was the most likely to be seen by people who would know about such things. There isn't a generic speaker forum where threads that cross topics can be posted (at least, not that I've found), so I had to choose.

 

[GM]

listening below 70dB is a great way of judging tonal balance in a loudspeaker system.........

Guess we'll have to agree to disagree since they use to put an adjustable 'loudness' control on pre-amps/receivers to boost the highs and lows to present a tonally balanced response at lower SPLs due to how we attenuate these BWs to allow for good speech intelligibility in our most acute hearing BW all the way down to whisper levels if the ambient noise level isn't too high.

GM

 

[borispm]

GM, do you mean the pre-amps/receivers we use have some sort of built-in equalizer to compensate for the Fletcher-Munson curve?

By the way if they do not have built-in equalizers, I still can't agree that listening below 70dB can judge tonal balance easily unless you have a reference, say you listened to a certain loudspeaker that you find "neutral" at higher SPL and you remember the sound signature of that speaker in lower SPL, which is, IMO, not easy at all!

 

[GM]

GM, I've read through most of Roger's site but thanks for the heads up. You've made me think, though, that a rated spl at 1m doesn't mimic my listening situation, which is about 10 or so feet from the speaker. That might be an advantage of a line array if in fact it somehow holds it's output with distance (I suppose I can see it isn't subject to the usual spherical radiation losses). But again, at 10' or so, maybe I wouldn't gain much via this consideration, and it's probably offset by the EQ losses.

You're welcome!

There's some others, but I guess you've already found them in a search.

Horns are like arrays WRT to loss over distance, though they don't project as far unless quite long, i.e. it needs to have a path-length at least as long as the array is tall, so impractical and I imagine a major reason why short horn arrays are so common in prosound now, so for max efficiency at the LP, use either a horn loaded array or DSL synergy concept horn and separate sub system.

SPL falls at a doubling of distance, so in free field, 10 ft = 20*log10(~3.2808/10) = ~ -9.68 dB, a huge amount when there's only flea power available, though in acoustically small rooms there's usually a lot of reflective energy that will reduce this over some BW to as little as 3-4 dB, but even then this is unacceptable at low power; so as one starts to confine it for better control/reduced reflections, it's best to design based on it rather than maybe coming up short since it's always better to 'cut' rather than 'boost' when it comes time to EQ it ~flat at the LP.

GM

 

[tinitus]

I posted here in the fullrange forum ..........

LB12

and a new design from Troels Gravesen
http://www.troelsgravesen.dk/DTQWT-12.htm

 

[GM]

GM, do you mean the pre-amps/receivers we use have some sort of built-in equalizer to compensate for the Fletcher-Munson curve?

By the way if they do not have built-in equalizers, I still can't agree that listening below 70dB can judge tonal balance easily unless you have a reference, say you listened to a certain loudspeaker that you find "neutral" at higher SPL and you remember the sound signature of that speaker in lower SPL, which is, IMO, not easy at all!

Well, the feature gave a smiley face EQ similar to a phono's EQ. Don't know if it's programmed into all modern electronics, though I've seen some that offer it as a 'night' or similar audio selection in the menus of some HT receivers, DVD/Blu-ray players and big screen TVs. Never researched the design details of either to see how well it might match any hearing curve.

Agreed, it's a rare memory that can retain a speaker's 'sound byte' pace, rhythm and timing (PRAT) for more than a few seconds much less over a longer segment with highly varying dynamics and average SPL levels.

GM