DIY Speaker Advice

cjmurphy87

Member
2011-06-10 3:25 am
Hi Folks,

Sorry if this is in the wrong forum, but with the way the speaker sub-forums are divided I wasn't sure on the best place for it as I want to discuss multi-way and full range options. Mods feel free to move.

I'm planning on building a 10w - 15w PP amp this summer, quite possible with the ability to switch betweeen triode and pushpull modes. I currently have a set of not so great but not so terrible commercial speakers that will remain nameless. They are in the low 90dbl/w/m range sensitivities by my own measurements a few years ago. If I remember right I also do my listening in the 80-90dbl range (determined at the same time), but I do not have access to an SPL meter presently so cannot reconfirm that.

The tweeter in one channel has started to go out, and is getting intermittently fuzzy and hissey. I've seen that this is not the first set this has happened to, and replacements are not available. I was planning on upgrading eventually anyway.

As I'm moving away from solid state and towards valve gear, I thought I would ask those with the more experience for some suggestions on DIY designs.

I don't feel competent enough to do my own design from scratch. but I'm an OK woodworker so even complicated cabinet designs are fine.

I've got about $250-300 to spend on drivers.

I've tended to like 2 way speakers in the past. I listen to a lot of rock, and have found usually if a speaker is going to let me down it will be in the bass range.

I've heard Dynaco A10s and A25s, and quite liked them for vintage speakers.

As such I started looking around at well regarded paper cone woofer designs
such as these: CA18RLY/22TAF-G (especially since I liked the Dynas, which used Seas drivers), and looked at some of Paul Carmody's designs (I'm currently building his boom-box as a gift, and had thought about matching his "Classix II" design with a solid state amp I have. However, sensitivity in these designs seems like it may be too low, and the impedence plots not flat enough from what I've read? I also looked at Zaph SR-71s but have read they are a bit sterile.

For full ranges I've looked at various Fonken types, and am particularly intrigued by the Frugel Horns. My worry with these is their bass performance, and if using a "helper woofer" or sub getting them to integrate well.

Presently I'm forced to sit very close to my speakers, in a small room. Probably about 1.25-1.5 meters, if I were to build floor standing speakers or stands I could probably get that to about 2 meters tops.

I listen predominantly to rock, but also jazz, folk, blues, and other types of music as well.

Thanks!
 
I went the "full range" route when I got in to lower powered amps. I built some fostex back loaded horns. I ended up w/ super tweeters on top, and a couple of subs in the corners of the room. So, in the end I guess it's almost a 3way system, w/ an extremely wide-range mid driver. (The horn is not filtered, but the tweeter and sub obviously are)
But, I love them! I've sense built other peoples 2 and 3 way designs, and the 'full range' horns are still my favorite.
I have trouble getting the subs integrated into the room, with some quiet spots. But in general, matching the tone w/ the horns hasn't been bad.
 

cjmurphy87

Member
2011-06-10 3:25 am
Wicked, which horn did you build? Was it your own design or one floating around. The fostex driver was 1 I was considering for the Frugel Horn.

lduarte1973: Those Zaphs look great, and just bearly squeak into my budget depending on crossover component choices. However, this set of speakers will be used almost exclusively for near field listening, I wonder if those would be well suited for that. Having looked them over I do want a set for my living room now!
 
Presently I'm forced to sit very close to my speakers, in a small room. Probably about 1.25-1.5 meters, if I were to build floor standing speakers or stands I could probably get that to about 2 meters tops.

Alpair 10.2/3 would probably work for you in a small room with the power of your upcoming build. Especially if you go for a smaller stand mount design with powered sub, versus the floor standing Pensil boxes, which in most instances don't really need a sub.

Alpair 12p Super Pencils are probably just too big physically for a small room.

jeff
 
Wicked, which horn did you build? Was it your own design or one floating around. The fostex driver was 1 I was considering for the Frugel Horn.

Fe166 drivers and I built the cabinets per the fostex plans for that driver.
I listen to them very far off axis (due to my living room arrangement), which is maybe why I needed the extra tweeters (which are angled towards my listening position).
 
Any other suggestions? I want to stay away from subs, so most/all of the full range designs I looked at are probably out.

I've read up on LRC impedance correction circuits, so the mid-range impedance spikes that many of the 2-way designs I was looking at have are less of a concern if I can correct for them. Anything else in the 90+ dcb/watt range for 2-ways?
 
Balerit, I assume you are refering to Troels' TQWP? I haven't been able to located a North American source for the driver.

Mor2bz, those look good, I'll have to track down some reviews of them and hopefully a frequency response, etc, plot. Shipping might kill my budget though.
 
Balerit, I assume you are refering to Troels' TQWP? I haven't been able to located a North American source for the driver.

Mor2bz, those look good, I'll have to track down some reviews of them and hopefully a frequency response, etc, plot. Shipping might kill my budget though.

There are several designs out there and are based on the work of Voigt, the sound though is amazing, especially coming from such a small speaker..
 

AllenB

Moderator
Paid Member
2008-10-18 11:31 am
the mid-range impedance spikes that many of the 2-way designs I was looking at have are less of a concern if I can correct for them.
Yes. Where the output impedance of the amp is high (is a significant portion of the load (speaker) impedance), it will drop a varying driving voltage across the speaker impedance. The applied voltage, when plotted, will resemble the impedance curve in shape.

If you plan to run triodes single-ended with no feedback, the output impedance will be high, however the typical commercial configuration of feedback amplifier should have low enough output impedance that this doesn't much matter, just as with most solid-state amps.

If you correct the speaker impedance then the output impedance of the amp won't matter. Another thing you can do instead is use a 4 ohm tap for an 8 ohm speaker as it has a different output impedance.

With common two way speakers I have often had success using just one RLC filter. Sometimes a bass impedance peak can be left in place as it will cause a reasonable boost in the bass, but only with the higher output impedance amps.
 
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High Efficiency speakers are an interesting area, and some of them can sound EXTREMELY good:
Audio Note AN-E Lexus Signature loudspeaker | Stereophile.com

Troels spends a lot of time on them:
High Efficiency Speakers

Here's a 90dB (or so) design known as the WLM La Scala which regulars know interests me greatly. A second order tweeter gives the sort of impedance we can equalise. Visaton drive units. In practise I found the efficient DT94 mylar and SC10N soft dome worked very well too on the same crossover.

[IMGDEAD]http://imageshack.us/a/img525/9297/wlmlascalaloudspeaker.jpg[/IMGDEAD]

It's a bitch to get phase aligned on it, which is what the RC across the bass coil is all about, but it's got some nice qualities. For SET use, I'd go for large closed box around 30 Litres or more, because reflex is really not good in that application. Then works very well as a standmounter with the impedance correction for SET, even extending the bass performance nicely.
 

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Hi,

I've got about $250-300 to spend on drivers.

I've tended to like 2 way speakers in the past. I listen to a lot of rock, and have found usually if a speaker is going to let me down it will be in the bass rang

The Nomex164 are OK for rock music and they can play very loud :)

PEERLESS-NOMEX-164

Construction d'enceintes "Nomex 164" - Le blog de pguerin

Troels Gravesen wrote :

"They deliver a punchy bass that even can be felt. Do not expect anything in the 20-40 Hz range. If you look for earthquake experiences, add a decent 10-12" sub. I actually think these speakers are excellent for this application and you may try adding a small amount of foam to the vent to make an aperiodic tuning to fine-tune sub-sat integration."

I can confirm all this, bass can be felt and it can be a VERY good system coupled with a sub.