Mike's Project - Background

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I expect to raise several questions in the process of deciding what to build, so here is the general background.

My tastes are classical, jazz, popular, folk, some rock; accoustic and female vocals in particular. I generally like the emotional and persuasive things - eg Loreena McKennitt, Grace Griffith. But I do like some life to the music.

My amp is a 300b SET and this suits my musical taste very well. I don't need headbanging volume and the SET seems to give just as much volume as a Naim NAP140 or 45wpc pentode EL34 amp. I am not going to change the amp - I'm an SET person.

The room is 18ft x 14ft, well furnished.

WAF constraints mean a max size of 8ins wide, 40ins high and though depth is less critical, say 12ins or so. I can probably exceed one or two of these slightly .....

I would prefer near wall positioning (even if this compromises the sound somewhat), for domestic harmony. The speakers will be on a long wall ie firing across the room.

Present speakers are IPL S3 kit trans lines using 6.5 inch SEAS bass and 1inch SEAS soft dome tweeter; about 16 years old. I enjoy them; they work well with the SET.

Why change? Well, I've heard a few interesting things making me consider changing. I heard some cheap Eltax MTMs using 5inch drivers, expecting boom tizz and harshness and in fact heard a very musical result; detailed, smooth, pleasantly lively (I nearly bought a pair). I'd say they were more detailed, open and lively than the IPLs.
Also I hooked up an old pair of Monitor Audio MA14's (got them free but with foam rot); they sounded smoother and more complete in the midrange; overall, slightly better than the IPLs.

So (though I still enjoy what I have) I'm looking for new speakers, probably DIY. Budget is say £1000 but I can go quite a bit higher.

Or do I forget DIY and go for something like:

http://www.cheerymusic.com/shownewsone.php?autonumber=121

I enjoy DIY (built my own valve gear) and by making speakers I expect to gain by using thick materials, improving the bracing, using good components in the Xover, and getting a good finish. Saving money isn't the primary objective.

I'll be posting several specific questions about possible kits or designs; but if anyone knows something that should suit me, fire away!
 
Some pretty decent designs at

http://www.planet10-hifi.com/boxes.html

Having built quite a few of the posted designs, I'm personally most fond of the Fostex FE126 in FrugelHorn or Ron Clarkes Austin A126, and the FE127 in Fonken and PAWO. The latter is wider than your 8", but can be built pretty enough to overcome most WAF issues.

I'm also a big fan of lower powered SET amps, particularly DHT such as 45/2A3/300B. From my personal listening experience with a variety of these amps on similar musical genres, I think you'll find the midrange performance on female vocals, acoustic stringed and percussion quite goose-bumpy, as well as the dynamics and bass articulation on the BLH designs.


IF you do decide to DIY speaker cabinets, please consider the lower mass/strategically braced approach using baltic birch plywood vs super-thick, massive / overdamped MDF etc.
 
chrisb said:

IF you do decide to DIY speaker cabinets, please consider the lower mass/strategically braced approach using baltic birch plywood vs super-thick, massive / overdamped MDF etc.



Thanks for the interesting link which I'll follow up.

Re the build suggestion - yes, I'll look into this; possibly in combination with laminating the sides to give a curve as this gives such high rigidity. My woodwork skills can just about manage this (I've built or rebuilt several wooden boats in my time).

Regards
Mike
 
Administrator
Joined 2004
Paid Member
Hi Mike,
An interesting problem you have there. Size constraints are the hard part. But I understand WAF, for sure. Remember- you may think it's your living room, but she will set you straight. ;)

My experience with SET and low power Class-D amps is that they need a big speaker to really thrive. Most of us just don't have the room for them.

Have you looked at the BIB projects in the Full Range forum here? Very well within your budget and dead simple for any boat builder. They ladies seem to like them, too. Most are taller than your specs, but that may not be an issue, especially if they go in the corners.

Not expensive or difficult to try, even if you decide you don't like them.
 
Some Possible Projects

First, though the Castles I mentioned seem good (an ex demo pair is on Ebay), I'll go for DIY as I like building things and have got good results in the past.

After a lot of looking around I've come up with some possibles.

Project A:
Zaph's MTM:
Vifa XG18 / Seas 27TDFC MTM - A large MTM with smooth clean sound
http://www.zaphaudio.com/audio-speaker16.html
Floor standing vented option.

Project B:
SEAS 27TDFC + PEERLESS 830875 Nomex
http://www.rzaudio.com/rz52/rz6.htm

Project C:
Project B but using TL loading.

Some comments.
Zaphs MTM exceeds the WAF dimensions slightly but this can be addressed. First, if I use the XT driver ilo the XG, this has slightly lower Vas so I guess I can reduce the box volume in proportion.
Baffle width - I guess at cheating a touch and reducing this by 0.5 inches. Should end up marginally outside desired dimensions without spoiling a good design (I hope).
The XT is marginally more sensitive than the XG (1dB or so), easily compensated for by tuning the dropper resistor on the tweeter.
This should give me the sensitivity I'd like, very high quality sound, excellent midrange (I'm told), and reasonable quantity of bass of a quality and nature that should suit me.
Does anyone know if it's tube friendly?

Project B:
Fits right into my desired size limits; uses high quality drivers; the mid/bass at 88.6 dB/w gives enough sensitivity.
I guess the issue might be whether the bass would be enough? The driver has Fs of 48Hz, this design has F3 of 39Hz which may be OK I guess; I like the idea of " The end result is a speaker with a very nice tonal balance with extreme smoothness.... no harshness here at all ".
There's the posibility of trying a parallel Xover as well (though I'd need help with the design).

Project C:
As the Peerless Nomex driver has highish Fs, plenty of Xmax and
Qts 0.39, I *guess* it might work OK in a TL (I'll do some more work here). A line of 1.7 metres might just fit within my package.


I have a feeling that all of these would give a top quality sound that I would really like ..... am I deluded? :)

Any comments appreciated.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.