Beginner's speaker questions

[Jeb Jeb]

I'm feeling the pull to build another bottlehead kit and am seriously considering the Stereomour II.  I would also like to build the speakers (probably from a kit or flat-pack) to go with it, so has begun the process of working out what to do.

I'm trying to understand what will be a good match for the amp, my room, and my listening habits.  I currently have some small Rega RS1 bookshelf speakers I use with a Naim integrated.  I used a meter to check what volume I listen at with a good range of music I like (a bit of everything, but rarely classical).  I pushed the volume up to what I would consider to be a little bit beyond obnoxious party-level.  I live in a flat so that would be extremely infrequent if at all.  It seemed very loud to me.  Room is about 5m x 5m with 4m high ceilings. Hard floors.  Quite lively I would say.

At 1m from the speaker the meter showed about 80dB and the maximum peak recorded was around 93dB.

- I understand the Stereomour II is 3.5wpc, which gives about a 5dB increase (?), so if I wanted to achieve that 93dB peak at 1m I would need to choose drivers with 88dB sensitivity

- If I wanted to forgo the ability to play overly loud then I presume it would be safe for me to drop a couple of dB perhaps to 86dB speaker sensitivity


1) am I on the right lines and doing this correctly, and are there other considerations? 
2) Do I need to allow for more headroom for any reason?
3) Does the cabinet the drivers are in have an effect on the overall sensitivity?


thanks for your patience!

I was considering Frugal Horn with Alpair 7.3 (86dB) or 7p (87.5dB)  and wasn't sure if they would be okay but the above seems to suggest they might be okay, unless I'm way off track.

I found a good post here from Paul Joppa that got me started.

http://bottlehead.com/smf/index.php?topic=5648.msg54417#msg54417

[Paul Birkeland]

1) am I on the right lines and doing this correctly, and are there other considerations? 

You pretty much nailed the analysis for your situation.  When you look at some single ended tube amps available commercially, you'll see some power ratings that are sometimes called "peak power" or "music power", with much higher wattage figures.  With most zero feedback single ended amps, clipping happens pretty softly, and you could probably hit peaks on a Stereomour at more than 2x the rated RMS output without it being too noticeable.

3) Does the cabinet the drivers are in have an effect on the overall sensitivity?

That's a bit of a loaded question (no pun intended).  For the purposes of your analysis, I would just presume that the speaker sensitivity is that of the driver itself.  When you start adding crossover components, or use a horn in front of a given driver, the sensitivity can change considerably. 

I was considering Frugal Horn with Alpair 7.3 (86dB) or 7p (87.5dB)  and wasn't sure if they would be okay but the above seems to suggest they might be okay, unless I'm way off track.

Either of these should work well given the data you posted.

[Jeb Jeb]

Much obliged thank you!

I was pretty surprised how loud 80dB was.

[fullheadofnothing]

Is there a particular reason that this math adds up to replacing your 90dB speakers with lower efficiency ones...?

[Jeb Jeb]

Is there a particular reason that this math adds up to replacing your 90dB speakers with lower efficiency ones...?

Just the desire to experience a different kind of affordable speaker design, put it together myself and end up with a 2nd system that will sound different (ideally better) than the one I already have.

That, and I was working on the premise that a drop in efficiency wasn't really a consideration if I was still able to comfortably achieve well above my usual listening volume with no clipping.

The Rega RS1s are really the only speakers I've ever owned so I don't have much real-world experience to go on.  Do you find that higher efficiency is always preferable when it comes down to how speakers actually sound with the Stereomour II, regardless of listening volume ?

I'm definitely open to other options, the only constraint is I'm limited in size to about Frugal Horn dimensions. Say 900mm x 500mm x 300mm (h x d x w).  Stand-mounted speakers would be another option.  My wood-skills at this point probably only go as far as putting together a kit, or perhaps sending off a cut-list/CNC file to a local timber yard.

Thanks!

[M42]

I have a pair of FrugelHorn 3's with Alpair  7.3en drivers mated to my Stereomour. I find the amp drives them to satisfying sound levels, albeit in a small listening room. The FrugelHorn flat packs are well engineered...fit and finish is excellent. The Alpair's will require a long break-in period (I hated mine at first), that said, I'm now really enjoying them, I think they're quite good.

[Jeb Jeb]

I have a pair of FrugelHorn 3's with Alpair  7.3en drivers mated to my Stereomour. I find the amp drives them to satisfying sound levels, albeit in a small listening room. The FrugelHorn flat packs are well engineered...fit and finish is excellent. The Alpair's will require a long break-in period (I hated mine at first), that said, I'm now really enjoying them, I think they're quite good.

Thanks M42!

The kits do look good. I'm just trying to find someone in this neck of the woods who can supply one.

Do you use a subwoofer or feel the need for one?

[M42]

I'm not presently using a sub and feel I likely won't need one. I have the maximum amount of baffle material installed in the front of the horn (40 grams). The bass response is well defined...not boomy or muddy (I claim no golden ear and lack the jargon to try and describe it in more detail). I may remove some of the stuffing to see how that affects the bass response, but for the moment, I'm quite happy with them. That said, in anything other than a small listening room, I can see how one might want to incorporate a sub.

If memory serves there was a gentlemen in the U.K building flat packs, and one in Holland. I have no further details unfortunately. I suggest you contact Dave Dlugos owner of Planet10 HiFi in Vancouver Canada. He will likely know of any suppliers in your area.

[email protected]

[Jeb Jeb]

Thanks!

I have been in contact with Dave - he did put me in touch with UK supplier, which will hopefully come to fruition!