Speakers for S.E.X - diy

[wullymc]

Hi guys,

I have been searching around but just want to be sure about sensitivity levels of speakers that would work for the S.E.X.

I have already built a Crack- and a Quickie and would like to transition to speakers so I am thinking of building the S.E.X.
When reading the product page it states that the sensitivity level of the speakers should be 97 in one place and 95 in another.

I have read that the Orcas pair well with them but on their page they are listed at 89db!
I would really like to try to build a horn with some Fostex but am confused as to what would be ideal.  The room that I will be listening to them will be around a 12 X 12 room.

The FE103 are 89db, FE126 are 93db, FE166 are 94db, and the FE206 are 96db.  MY question is how big a difference would 1 db be?
Would the FE103 or FE126 suffice in a 12 X 12 room?  I am thinking that the horn speaker for the 166's and 206's might be too much or too big!

The last thing that I would want to do is to build the S.E.X, invest the money, time, and effort to build the speakers only to be disappointed in the result of performance from the speakers.

Thanks....Dave

I

 

[Paul Joppa]

It's a really difficult subject to be precise about, because the variation among people is simply enormous. Here's my take:

1) Based on long-term observation of Stereophile magazine reviews, I have said for some time that "most audiophiles, most of the time, will be satisfied with a minimum peak power capability of 102dB per channel." This is essentially identical to the Dolby THX specification for home theater systems. SEX has 2 watts, which is 3dB above 1 watt, so a 99dB efficiency would meet this spec.

2) A study in the literature of studio recording and mastering engineers showd that they listen at a maximum level of 82dB per speaker. Other studies indicate that well-recorded analog (vinyl) music has a headroom of 14dB, so an instantaneous peak of 96dB should be sufficient - implying 93dB for use with the SEX.

The difference of 6dB relative to 1) above is easily attributed to explosions and car crashes, common in movies but not in music.

A different approach is offered by some engineers - solid state is said to have a loss of quality in the 6dB below peak power, so the "quality sound" range is 6dB less than the rated power. There are some technical rationalizations for this view, but the important part to me is that it's based on observation - tube amps generally can compete with solid state amps of 6dB greater power. (6dB is a factor of 4, so that's saying an 8-watt solid state amp can be competitive with a 2 watts tube amp.)

3) People's taste in music and loudness is highly variable. That's hidden in the phrase "most audiophiles, most of the time" used in 1) above.

For a small proportion, it is important to approach the sound of a live rock concert - that will take some 12dB more loudness, maybe more. If you do not already have significant hearing loss, a habit of this will provide it.  :^)

I think that, to hear the utmost resolution of a system (i.e. not just  to hear the music per se) you do need greater peak power capability - that 102dB capability at a minimum. Several audio pros (i.e. more than just music lovers) of my acquaintance really need this capability even though they rarely use it. These are guys for whose ears I have the greatest respect.

On the other side, for the average music lover (as opposed to audiophile) something like 6dB less peak loudness is perfectly fine - you can hear all the musical details, without offending housemates or neighbors. That gets you down to 87dB speakers with the SEX. For what it's worth, I myself use 89dB speakers with my SEX amp, DVD player and TV to watch movies and I've never even approached clipping levels. But then, we have almost every Jane Austen movie ever made (my wife's a fan) and no Bruce Willis movies at all.

Music makes a difference. I love symphonic music, and my biggest stress on a system comes when I listen to Mahler. My main system is 101dB efficiency with 8-watt Paramounts. I don't get to let it loose very often! If you like Brubeck or Joan Baez, you don't need anything like that.

4) Small live rooms need less power than large, dead rooms. Good for +/- 3dB I'd say, unless your room is really exceptional.

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Don't know if that's much help, but I tried to set the stage at least.

 

[Hank Murrow]

Dear wullymc and Paul;

I run my Orcas driven by a Custom BH 2A3 amp built by Paul Birkeland with Clark's subs filling out the bass(and taking a load from the Fostex 3" drivers) in a room 8' x 14'8" x 18'6" playing Mahler's Symphonies to impressive levels(C-weighted 89Db at 8 feet) from vinyl and compact discs. I have around forty recordings of these works, and some are rendered in stunning realism with this system. The source now constitutes the biggest limitation for me with this program material, as the BH/Blumenstein  system is very revealing. Barshai's recording of the Tenth is amazing! I heard Dudamel's rendition of this piece in Disney Hall a year ago sitting behind the basses and opposite the Dude and could not believe my ears. Stunning! So I can calibrate between the recorded sound and the live sound pretty well. YMMV, of course; but my 3.5 watts is plenty in my room. Cheers, Hank in Eugene.

VPI 19 with BPS EVO lll, into Custom BH Eros, or Oppo BDP-95 player into Custom BH Linestage, into 2A3 Amp into the speakers. No room treatment as yet.

 

[Natural Sound]

Hi wullymc. I fall into category 2 from Paul Joppa's reply. I typically listen around the 82dB during my normal listening sessions. I'm sure that the peaks are a little higher than that. For me personally that's loud enough. I occasionally push it harder than that and listen in the mid 90's range. I'm using a pair of Orcas and Orca subs. My amps are Paramour II 45's (approx 1.75W per channel) fed by a FPIII. I rarely have to turn the volume control to the 11 o'clock position to achieve these sound levels. That's measured with an el cheapo Radio Shack analog dB meter (33-2050) using the C Weighting option.

 

[Doc B]

Recording and mastering engineers typically listen at a level of 82dB when they are working in the studio. I can attest to the fact that the level goes up after hours when the cocktails are served.

 

[2wo]

I use Hornshopp horns, which use the FN126. With my 45 amp, at 1.7 W it plays plenty loud...John

 

[Clark B.]

I'll chime in here first to say that whichever speakers you should choose, you are definitely on the right track to be building the SEX amp, or any of Bottlehead's speaker amps.  They are very musical, and a detailed speaker setup is a great counterpoint to have around from a headphone rig.  The SEX amp was Bottlehead's first product, it was also the first amp of theirs that I built.

We have many people successfully using Orcas and SEX in a huge variety of situations, despite what would be an apparent mismatch of efficiency numbers. The feedback we keep getting is that there is a subjectively pleasing musical chemistry between the two designs.  Of course there is a volume limitation with the combo, but in my own home I rarely find myself asking for much more than the two are capable of together.  My tastes, however, are for a strictly "modestly loud" presentation most of the time (i usually listen to my music at close to the max volume before the sex amp starts to run out of steam), and sometimes i go for rather quiet listening at night.

Cheers!

Clark

 

[Doc B]

FWIW I plan to use S.E.X. amps with Orcas for 5.1 surround in my home theater. Loudness has not been an issue when I have tested a stereo S.E.X./Orca setup in there.

 

[wullymc]

Thanks very much guys for the feedback, especially to Paul for providing so much detail.  Truly appreciate it.

This forum is the best and as I neophyte I never feel embarassed to ask maybe a very simple question!

I think in the end I will try something like a back loaded Fe126en horn.    I will get to practice my woodworking skills to see what I can do!
This will be my summer project as I need to use my garage and it has been a long cold winter so far....damn you Polar Vortex! 

Take care.  Have a great weekend...Dave