High sensitivity 8 ohm drivers?

[Bill poster]

I bought a low powered valve amp, around 14 watts, so now thinking of a build to suit. The speakers cd be large or small, 2 or 3 way. But drivers no bigger than 8" and no less than 6ohm.
So far I see a few tangband FRs and faitals for mids. Peerless nomex 8" for bass unit perhaps.
Or 2 way, visaton b200, satori mw19p-4..
Any other suggestions?

 

[marco_gea]

I bought a low powered valve amp, around 14 watts, so now thinking of a build to suit.

Sorry to break it to you, but it appears to me you are approaching the problem from the wrong angle.

The speakers are responsible for 90+ % of the overall sound quality.

One should always choose the speakers first, and then look for the most suitable amp(s) to drive them, not vice versa.

IMO, with your 14Wpc valve amp, you'd really want at least 96dB/W(m) speakers to avoid major clipping on musical transients (> compression and DISTORTION).
AND, you must also ensure a pretty flat speaker impedance across the board, to avoid frequency response deviations induced by the amp's own output impedance.

Alas, there are NO real world 8" woofers that can get you there and still produce real bass (any commercial manufacturer claiming differently is just lying).

The only half-viable option would be an 8" wide-range driver in a back-loaded horn.
If that's not what you want or are willing to put up with, then you're out of luck, I'm afraid.

 

[hottattoo]

I totally agree with marco. You are deliberately limiting your speaker choices but it can be done---almost !! You can get a nice 2" compression driver and horn along with something like a Fostex tweeter using a simple crossover. For the woofer section I would biamp with a plate amplifier ( cheap and lots of choices ) or a better amplifier if your budget permits. Lots of factors come into play like room size, loudness level expected, lowest frequencies desired, overall sonic expectations. Good luck.

 

[system7]

I can't see a problem at all, TBH. 😕

My good friend marco_gea has built some splendid high efficiency speakers:

http://www.diyaudio.com/forums/multi-way/147632-classic-monitor-designs-25.html#post4428857

That is a 92dB Mivoc 8". You can get a similar Eminence closed box driver at Parts Express at the moment.

I usually get loud enough with a 20wpc solid state. And the splendid old Radford STA25 valve amplifiers were not much more.

I think this sort of Visaton W200S-8 plus TW70 thing (my current toy... LOL) ought to work:

Probably lose the reflex port, because valves can't control reflex, flatten the impedance and cross at 3.5kHz. Maybe make the box big too, which is good for efficiency. The SEAS U22 woofer and DXT tweeter gets to much the same place too. Joachim Gerhard said they were easy to filter. 😎

 

[nigelwright7557]

I would go for a high efficiency 12 inch full ranger to keep it simple.
Something like a Fane 12-250TC which goes up to 17KHz.

 

[Galu]

14W is an uncertain quantity. The actual rms power could be much smaller, or the 14W may only be achievable at a high level of distortion.

A high sensitivity loudspeaker system is therefore advisable.

Steve mentioned Eminence - what about this combination?

Alpha - 8A (8"; 8 ohm; 94dB/W woofer)

APT:80 (102dB horn loaded supertweeter)

PXB2:3K5 (assembled crossover which matches the above drivers)

 

[sony6060]

If you decide not to build, Omega makes sensitive speakers in the 95dB and higher range. I was looking at the Omega, but bought Revel M22s as a person compared them and stated the Revel were better sounding. Boy was he right, unbelievable sounding speakers. I would have to likely jump up to $4000+ for better sounding. The Revel M22 are 86.5dB sensitive.


I have a 12 watt per channel tube amp. Did not know if the amp could drive the speakers. The power seems fine for the speakers at listening volumes I use. But, I just bought a 35 watt per channel tube amp and will upgrade it for best sound. I shall find out if higher power is better.


I bought speakers as first priority and then find a suitable amp to drive the speakers. 35 watts with more reserve power may be better. Speakers first, amp next in line. Not the other way around.

 

[phivates]

It IS the other way around, because the OP says so. Respect the thread for what it is people, and contribute. Now then...96 db/watt systems are not as simple a challenge as they should be, since LF driver specs often quote the peak output in the mid band, not overall. The big Fane full rangers are definitely in the conversation. Something big most likely...
OOPS I should pay more attention to post #1

 

[Bill poster]

Double post

 

[Bill poster]

I'll be straight up, the amp was bought to support a friend who has a small business making valve amps in Thailand. This system is in a small condo where I can't crank it up. I feel it's equivalent to 20-25 watt SS amp, it's around half volume for normal listening with the fairly inefficient speakers I'm using now.

Thanks for your suggestions, maybe an old school wide baffle 2 way? Something based on an existing diy design is fine

 

[hollowboy]

drivers no bigger than 8" and no less than 6ohm.
[...]Any other suggestions?

You didn't say how many 8" drivers. These use 2 x 8" and seem to hit your targets nicely.

Denovo Audio Alchemy-88 Center Channel

Denovo Audio 88-Special

 

[midrange]

I think your old school wide baffle idea is good. You really want to avoid any need for BSC, so if not wide baffle you want to have the speakers near the wall behind them.

 

[Lojzek]

Hey Bill,

can you disclose more info on your new amp?

 

[gazzagazza]

Seriously consider the Fane mentioned a few posts up. It just needs a sealed box. There is a thread discussing it here on diy.

 

[Bill poster]

Hey Bill,

can you disclose more info on your new amp?

It's by a company called Mark Audio in Thailand, no relation to the driver brand. Single ended amp, bought with KT88's with the understanding that it cd use KT120s, (just done)

 

[Bill poster]

Those Fanes look really good but the boxes wont get past the wife, even close to wall.
Another route is to use a spare pair of Alpair 10p's( i forgot i had)in a quick and dirty horn design..
Will go to Ban Mo market in a couple of days and see if any of the above drivers are sold there.

 

[Lojzek]

I would suggest something like Troels' kit Quattro mkII with the addition of impedance flattening filters. A very good compromise between spl and low end response.

 

[Bill poster]

I would suggest something like Troels' kit Quattro mkII with the addition of impedance flattening filters. A very good compromise between spl and low end response.

Thanks, will read up on these. I'm gonna make a quick mltl this wknd with some spare drivers I forgot I had. Not quite what I had in mind but might just work for this amp.

 

[Bill poster]

That driver in the kit is very interesting Lojzek. Quite low qts, but def the best compromise for that size. Similar ish parameters to one of the accutons

 

[system7]

I wonder if we are making this more difficult than it is?

You just need an efficient speaker here, and 8" bass IS efficient.

I expect a pair of old Whafedales would do a nice job.

But you can always go for the valve-friendly closed box and flat impedance if this is a SET amp with low feedback. This sort of thing below actually gives better, deeper bass with SET. A goodish crossover, I think, but work it out for yourself! Fourth order tweeter. Plenty loud.