Why is it impossible to find a pair of 2-way 8ohm speakers of (min) 89 dB sensitivity for less than a small fortune and under a metre high (3ft 3"). I have a pair of Tannoy M15 from 1991. They are only 19" x 10" x 8.5" (48 cm h x 5.5cm w x 21.5 cm depth) and have those exact specs. My 2w/ch Bottlehead SET headphone amp gives decent enough volume in my small room.
I want to upgrade my speakers - to build my 'end speakers' - the last pair I'll ever make. They'll need to be efficient so I can use low watt amps (6- 8w). I've decided on a small tower with a small footprint - it will be close to the back wall. Are there any decent kits/designs out there with a minimum sensitivity rating of 89dB- pricing somewhere between an expensive Troels Graven and cheaper 2 Pi Tower speakers (don't fancy using a driver made for a bass guitar amp for my hifi)!!?? I've been on every diy audio site for the past month or so, as well as looking at off the shelf speakers too. There's the Klipsch RP600M, but they have an awful dip in the frequency response in the upper mid/low highs. Plus we all know that we could make a better speaker for the money - but with 96db - how?
I've been down the single driver road (Fostex 208Sigma). Not impressed - huge cab, week bass, would have to build a subwoofer too.
So 2 questions;
1. Why no 'Goldilocks' speakers - decent bass, not huge, not inefficient??? Tannoy managed to produce them 30 years ago, so why not now?
2. Why does sensitivity reduce when a driver is put inside a cabinet? I found a design I like - the WD25t that has the Seas A26RE4 woofer (89 dB) but the finished speaker's sensitivity is 87dB.
My max budget is £1000 total (including all components and wood, paint etc). If you have any answers or suggestions, please leave a comment.
Thanks
I want to upgrade my speakers - to build my 'end speakers' - the last pair I'll ever make. They'll need to be efficient so I can use low watt amps (6- 8w). I've decided on a small tower with a small footprint - it will be close to the back wall. Are there any decent kits/designs out there with a minimum sensitivity rating of 89dB- pricing somewhere between an expensive Troels Graven and cheaper 2 Pi Tower speakers (don't fancy using a driver made for a bass guitar amp for my hifi)!!?? I've been on every diy audio site for the past month or so, as well as looking at off the shelf speakers too. There's the Klipsch RP600M, but they have an awful dip in the frequency response in the upper mid/low highs. Plus we all know that we could make a better speaker for the money - but with 96db - how?
I've been down the single driver road (Fostex 208Sigma). Not impressed - huge cab, week bass, would have to build a subwoofer too.
So 2 questions;
1. Why no 'Goldilocks' speakers - decent bass, not huge, not inefficient??? Tannoy managed to produce them 30 years ago, so why not now?
2. Why does sensitivity reduce when a driver is put inside a cabinet? I found a design I like - the WD25t that has the Seas A26RE4 woofer (89 dB) but the finished speaker's sensitivity is 87dB.
My max budget is £1000 total (including all components and wood, paint etc). If you have any answers or suggestions, please leave a comment.
Thanks
There are multiple reasons why final sensitivity is lower in finished speakers than the raw drivers. For direct radiating speakers, it is impossible for sensitivity to be higher. That said, for an 8 inch driver to be more sensitive than 90dB you must give up bass extension or undistorted output. Since power is cheap and plentiful these days with class-D amplifiers, there is little reason to make high efficiency drivers. The ones that are can command higher prices. I have a similar beef. I like extremely high compliance drivers, ones that can only be used in sealed enclosures. Nobody makes these any more. All drivers are now designed for small sealed and vented applications, and therefor have tight suspensions.
Unfortunately bass extension, small volume and efficiency are all directly related. You can have 2 out of 3 but not all 3, you choose the characteristic to leave out. Due to the availability of cheap power, hi-fi driver manufacturers have opted to sacrifice efficiency, most 8" today can go in the lower 30s. As for your current speaker, I suspect that either Tannoy cheated on the sensitivity specs or the bass extension is pretty limited for a (today) 8" driver.
This depends on the baffle step effect, and the correction that the speaker designer has chosen.
Ralf
Everything everyone else said about efficiency, size, low end extension holds true.
Looking at the values for the Tannoy M15s
Tannoy M15 Series 90 - Hi-Fi Database - Bookshelf and Standmount Speakers
or a brutally honest sound review at Tannoy M15 (large used dealer in Italy with evaluations, in Italian though) lets one assume that the 89 db efficiency is very optimistic, I assume you are looking at around 86-88 db/2.83 max across the spectrum and as they have a listed frequency range of 48hz - 20khz traditionally this would be f8 or f10, I assume, probably also in room, commercial speakers in that era listed the lowest frequency that you could produce vs. F3 (point at which the bottom end exceeds a dip of -3db to the rest of the spectrum, F8 is -8db F10 is -10 point)
They are listed as having a nice top end and mids for the price AND a bass that will not bother ANY neighbors
Also good excecution of the metal dome (no harshness) and integration with mids.
If you are running 6-8 watt SET forget about really good bass below 40hz with 8" speaker. It will be difficult to have the power to move the membrane well at those frequencies unless you add horns. But that is not a problem, sounds like you are happy with the bass.
So you should not have a problem finding an ca. 87-88db/2.83V DIY stand mount with f3 in the 50hz range because that is what you are replacing and DIY speakers tend to have much more honest measurements than 1990s commercial speakers, or even many today
There are good DIY high efficiency speakers using pro audio drivers that will fit the bill, not many commercial ones, especially <$1000. Now if you put those 8W in a >91db/1W with large membrane area you will have a traditionally good speaker for your amp but it will be bigger. No getting around physics here. But it seems like you are happy with what you have and can live with the distortion and/or low SPL of sucha speaker. Troels and many others make suitable speakers.
My recommendation would be getting something like Troels 861 for less than $1000 in the top configuration. Then you can see what time aligned, fairly high efficiency 91-92, 1st order, with good modern cost effective drivers, high quality caps, minimal crossover, exceptional design IMO, will do for an SET A little taller, but similar footprint than the M15, but you get a 8" plus 6" in 2.5way, almost the membrane of a 10" that could produce good bass even with 6-8 watts, and less distortion due to more membrane area and efficiency. I heard it with 14 watts SET and ridiculously colse wall placement less than 50cm, in a ca. 30m² room, incredible for the money.
But there are many other options, you just need to know what you want. Straight replacement or something better and what are you willing to have size wise. Many good simple 8" two ways out there.
Good luck
Looking at the values for the Tannoy M15s
Tannoy M15 Series 90 - Hi-Fi Database - Bookshelf and Standmount Speakers
or a brutally honest sound review at Tannoy M15 (large used dealer in Italy with evaluations, in Italian though) lets one assume that the 89 db efficiency is very optimistic, I assume you are looking at around 86-88 db/2.83 max across the spectrum and as they have a listed frequency range of 48hz - 20khz traditionally this would be f8 or f10, I assume, probably also in room, commercial speakers in that era listed the lowest frequency that you could produce vs. F3 (point at which the bottom end exceeds a dip of -3db to the rest of the spectrum, F8 is -8db F10 is -10 point)
They are listed as having a nice top end and mids for the price AND a bass that will not bother ANY neighbors
Also good excecution of the metal dome (no harshness) and integration with mids.If you are running 6-8 watt SET forget about really good bass below 40hz with 8" speaker. It will be difficult to have the power to move the membrane well at those frequencies unless you add horns. But that is not a problem, sounds like you are happy with the bass.
So you should not have a problem finding an ca. 87-88db/2.83V DIY stand mount with f3 in the 50hz range because that is what you are replacing and DIY speakers tend to have much more honest measurements than 1990s commercial speakers, or even many today
There are good DIY high efficiency speakers using pro audio drivers that will fit the bill, not many commercial ones, especially <$1000. Now if you put those 8W in a >91db/1W with large membrane area you will have a traditionally good speaker for your amp but it will be bigger. No getting around physics here. But it seems like you are happy with what you have and can live with the distortion and/or low SPL of sucha speaker. Troels and many others make suitable speakers.
My recommendation would be getting something like Troels 861 for less than $1000 in the top configuration. Then you can see what time aligned, fairly high efficiency 91-92, 1st order, with good modern cost effective drivers, high quality caps, minimal crossover, exceptional design IMO, will do for an SET
A little taller, but similar footprint than the M15, but you get a 8" plus 6" in 2.5way, almost the membrane of a 10" that could produce good bass even with 6-8 watts, and less distortion due to more membrane area and efficiency. I heard it with 14 watts SET and ridiculously colse wall placement less than 50cm, in a ca. 30m² room, incredible for the money.But there are many other options, you just need to know what you want. Straight replacement or something better and what are you willing to have size wise. Many good simple 8" two ways out there.
Good luck
Oddly enough, 98 db 1w1m is commercially available in a speaker that is +-3db 54-17 khz. Harmonic Distortion is down 25 db 2nd & 3rd harmonic 5 W 54 hz-12 khz. Peavey SP2g post 2004. Who else even charts harmonic distortion?
I've heard them; they can sound very like a Steinway grand piano with right source CD.
I had SP2-XT that were bigger and 101 db 1w1m. Sounded great but no distortion spec. No longer in production. Great dispersion all over my 14'w 33' long 11' high music room: when set up near ceiling on poles. I listened at 1 v pp base level (pp) about 1/4 W @ 8 ohms.
I've heard them; they can sound very like a Steinway grand piano with right source CD.
I had SP2-XT that were bigger and 101 db 1w1m. Sounded great but no distortion spec. No longer in production. Great dispersion all over my 14'w 33' long 11' high music room: when set up near ceiling on poles. I listened at 1 v pp base level (pp) about 1/4 W @ 8 ohms.
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Klipsch.
I have a few new pairs, and a new set of THX-6000 LCR for bench speakers (just the L and R). Really, really good speakers, 98 db/ watt I think. Extremely flat and low THD. Expensive.
The towers that use dual 8" drivers and Tractrix horn are excellent and 99 dB/watt I think. Buy a used pair - or new. They sound excellent and you cannot her the transition to the horn (which sounds like a dome tweeter).
I'm listening to the THX-6000 LCR right now.
-Chris
I have a few new pairs, and a new set of THX-6000 LCR for bench speakers (just the L and R). Really, really good speakers, 98 db/ watt I think. Extremely flat and low THD. Expensive.
The towers that use dual 8" drivers and Tractrix horn are excellent and 99 dB/watt I think. Buy a used pair - or new. They sound excellent and you cannot her the transition to the horn (which sounds like a dome tweeter).
I'm listening to the THX-6000 LCR right now.
-Chris
A modern high quality speaker will be driven by a power amplifier with a few hundred watts and this is reflected in the size, bass extension and sensitivity of modern high quality speaker designs.
If you want a more unbalanced lower quality design to match your low power amplifier then the choice is going to be more limited. You will have to choose how much size and bass extension you will trade to get unusually high sensitivity or, alternatively, accept that the speakers will be unable to reproduce clean transient peaks at standard levels. You haven't made this clear although the small tower suggests you want normal sized speakers. So how much are you prepared to surrender in terms of bass extension and/or sensitivity required to play clean transients at standard levels?
The design you cite uses a single retro design of midwoofer (large resonant cone with modest motor) which isn't used in modern speakers anymore for reasons of sound quality. A more modern approach might use 4 smaller and better behaved midwoofers in a 2.5 way arrangement. The Elsinore speaker would be an example of this approach offering better sound quality, higher efficiency in the region of 93 dB, tower format, £1000(ish) budget (the high value for money midwoofers are £50 each).
Hi Andy,
That speaker project you are talking about was geared to current drive if my memory serves correctly. Not ideal.
Low bass is more a question of physics. The lower you want to go, the larger the box will be keeping efficiency the same. We can create a tiny box, treat the woofer as a piston, but that forces you to hit it with hundreds of watts of power. This would not be a full range design, just a sub.
So go check out some speakers. I am very familiar with Klipsch over a period of over 30 years, so I can recommend them. Other brands may be just as good and valid, and they are out there. Generally, when you start demanding things beyond classic good design, the dollar figures begin to really climb.
-Chris
You have generalized way too much here. Modern drivers can now be made to be very efficient - but that costs money.
That speaker project you are talking about was geared to current drive if my memory serves correctly. Not ideal.
Low bass is more a question of physics. The lower you want to go, the larger the box will be keeping efficiency the same. We can create a tiny box, treat the woofer as a piston, but that forces you to hit it with hundreds of watts of power. This would not be a full range design, just a sub.
So go check out some speakers. I am very familiar with Klipsch over a period of over 30 years, so I can recommend them. Other brands may be just as good and valid, and they are out there. Generally, when you start demanding things beyond classic good design, the dollar figures begin to really climb.
-Chris
In general I agree, but as a mid/bass something like the well-behaved Fane Sovereign 12-300 is very good value for money around these parts.
I also like the Fane fullrangers, 15-300TC and 12-250TC, but they do require a bit of adaption to get just so, still less work than lots of crossovers and stuff.
A currently interesting case to look at for a trend back to efficiency is the new Revel F328Be vs the Salon 2. A decade of development and different cabinets, but overall similar objectives from Harmen. One of the differences is that the F328Be is 91dB sensitivity to the Salon 2's 86dB. It seems many prefer the F328Be for all but the deep base because of its dynamics. The Salon 2 has a -3dB in the low 20s, so the trade off is obviously bass extension. I think with affordable subs and the prevalence of multiple subs you can trade off for a more efficient speaker, but that -3dB on the stat sheet is a sales differentiator for some (tbf the 328 -3dB is still a good floorstander 35Hz).
Watched a few interviews with Harmen engineers talking about the comparison, worth it for a more apples to apples comparison than a pro audio horn speaker to a cone and dome home hi fi.
Watched a few interviews with Harmen engineers talking about the comparison, worth it for a more apples to apples comparison than a pro audio horn speaker to a cone and dome home hi fi.
Not at all. I am simply stating Hoffman's Iron Law. The laws of physics really do hold whatever the protestations from audiophiles with conflicting beliefs.
Not at all. It is the configuration of 4 midwoofers in a 2.5 arrangement that meets the OPs requirement of higher than normal sensitivity while still functioning well as a modern speaker at a reasonable price. I rather doubt many of the builders of the speakers are using current drive but I expect a fair few will be using valve amplifiers.
This is simply not true. It isn’t a problem of cost, a simple look at the T/S equations reveals that if you want high efficiency and good bass extension, you also need to have a (very) large volume. Period.
So the trend today is to provide drivers that are mid efficient, and go low so the volume needed is pretty low (the volume for a slim tower). Or go to PA drivers that offer high sensitivity with small volume but OTOH they don’t go low: a 8” PA driver has 95-100 dB efficiency but a Fs of maybe 80 Hz.
For the OP the best solution is an Econowave.
Ralf
Hi, adejacko
The minimum I would personally accept for " the last speakers I ever build" is a variation of an Altec 604 in a cabinet as narrow as possible. You could also have quality cabinets built if skill or tools are a problem. This all depends on the long term value you place on music and physical size constraints. Some of the vintage ( used ) mid size JBL speakers could also meet your demands. Good luck in your search.
Joe
The minimum I would personally accept for " the last speakers I ever build" is a variation of an Altec 604 in a cabinet as narrow as possible. You could also have quality cabinets built if skill or tools are a problem. This all depends on the long term value you place on music and physical size constraints. Some of the vintage ( used ) mid size JBL speakers could also meet your demands. Good luck in your search.
Joe
I would have to agree with Sin Phi that there is a strong movement in HighEnd, especially for those with dedicated rooms to go to more efficient designs. If it is the Revel, DeVores, Living Voice or any other top of the line speaker of many manufacturers, these through many drivers in D'Appilito or similiar tend to shoot at 91-94 efficiency. Just go to the Munich High End this year and see how many manufacturers will show case a low efficiency speaker, very few unless they use 300W+++ class A amplification. These audiophiles want the perfection but realise (or intuit) that what they are most often after is the dynamics and emotion that high efficiency speakers convey.
Regular higher consumer speakers care about WAF, and features and numbers. The amount of people that really loved high efficiency speakers and then end up buying a setup because of specs and then go for the upgrade cycles was one of the reasons I left high end audio installations.
You can make incredibly low distortion speakers (per SPL) with high efficiency (e.g. fieldcoils,horns) , or speakers with enough drivers to reach good efficiency, but now low distortion and efficiency and power and DSP are so cheap that people just go for that. But there is a counter movement as there was with vinyl towards more efficiency. The issue is as always stated size/WAF and cost. One has to admit that some dsp high power setups e.g. Kii 3 are getting quite good at conveying dynamics with ingenious speaker placements and 6 x250W dsp driven amps per speaker.
There was a youtube video about the coniseur to exhibitionist spectrum in audio, and most people are trending towards the exhibitionist spectrum or need reasurence with numbers. Or don't want a divorce
Back to recommendations for adejacko, it would be important to know how much would you be willing to go beyond in size the248 x 497 x 205mm of the m15, if you want better for 8 watts power you need to be a bit flexible. Looking at the prices for used speakers the M15 now sells for €45-75 for the pair in Europe and that is admittedly a bargain, but it does reflect that it falls in the sub $200 used price/quality category and with $1000 dollars you can get something far superior and probably more efficient used, or DIY, new will be harder. DIY D'Appilito with horn/high efficiency dome/AMT, etc. will get you where you want with about the same footprint as the M15swith stands better bass and far less distortion. Now listening to those DIY speakers is a different story in times of COVID
Good Luck
Regular higher consumer speakers care about WAF, and features and numbers. The amount of people that really loved high efficiency speakers and then end up buying a setup because of specs and then go for the upgrade cycles was one of the reasons I left high end audio installations.
You can make incredibly low distortion speakers (per SPL) with high efficiency (e.g. fieldcoils,horns) , or speakers with enough drivers to reach good efficiency, but now low distortion and efficiency and power and DSP are so cheap that people just go for that. But there is a counter movement as there was with vinyl towards more efficiency. The issue is as always stated size/WAF and cost. One has to admit that some dsp high power setups e.g. Kii 3 are getting quite good at conveying dynamics with ingenious speaker placements and 6 x250W dsp driven amps per speaker.
There was a youtube video about the coniseur to exhibitionist spectrum in audio, and most people are trending towards the exhibitionist spectrum or need reasurence with numbers. Or don't want a divorce
Back to recommendations for adejacko, it would be important to know how much would you be willing to go beyond in size the248 x 497 x 205mm of the m15, if you want better for 8 watts power you need to be a bit flexible. Looking at the prices for used speakers the M15 now sells for €45-75 for the pair in Europe and that is admittedly a bargain, but it does reflect that it falls in the sub $200 used price/quality category and with $1000 dollars you can get something far superior and probably more efficient used, or DIY, new will be harder. DIY D'Appilito with horn/high efficiency dome/AMT, etc. will get you where you want with about the same footprint as the M15swith stands better bass and far less distortion. Now listening to those DIY speakers is a different story in times of COVID
Good Luck