Troels tqwt is a speaker I would love to build one day. The problem is that once you add a shipping and the drivers and tax it is way out of my price range. Are there any more affordable alternatives available for this driver?
I was also wondering if someone could explain to me how Troels tunes the enclosure to increase the sensitivity of this driver as he mentions in the link below. I've never heard of this before and I thought sensitivity was solely a product of the driver(s) design and implementation. I.e. using two drivers in an mtm to increase sensitivity.
http://www.jantzen-audio.com/download/ja8008-tw034-kit/PD_JA8008_Aug10_v3.pdf
I was also wondering if someone could explain to me how Troels tunes the enclosure to increase the sensitivity of this driver as he mentions in the link below. I've never heard of this before and I thought sensitivity was solely a product of the driver(s) design and implementation. I.e. using two drivers in an mtm to increase sensitivity.
http://www.jantzen-audio.com/download/ja8008-tw034-kit/PD_JA8008_Aug10_v3.pdf
The seas CA22RNY looks nearly identical, it built on exactly the same frame with the same magnet, but uses a damped paper cone, as for the magnet gap structure (copper etc.) pass. (the Jantzen is built by seas to a design by troels) The RNY has high sensitivity (about 92 dB) and excursion and good distortion figures (klang and ton review) unlike the fostex which isnt really similar to the jantzen.
Hi,
The CA22RNY isn't as sensitive as the Jantzen due the the presumably extra coating and the
fact that its coil is 18mm long compared to the Jantzens 12mm, both have a 6mm magnet gap.
Double linear cone excursion = +6dB excursion limited max SPL and
due to the differences in sensitivity probably around 10 times the
power handling in the excursion limited region. The Jantzen does
suit low powered amplifiers, the Seas suits a lot more juice.
the Fostex's excursion limited bass SPL is very low, due to high sensitivity
so is the bass power handling, but it works with flea powered amplifiers.
rgds, sreten.
Hi,
Well if you want relatively high efficiency speakers at reasonable cost,
and have a decent 4 ohm capable amplifier probably check these out :
Zaph|Audio
A genuine 90dB/2.83v/1m with full BSC is not too shabby. Simple x/o.
rgds, sreten.
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one alternative driver:
8NMB420 - High Output MB Neodymium Driver
I used it (16ohm version) paired at 1.8kHz with a ScanSpeak 6600 and it is VERY good, efficient and of high fidelity.
However I don't know where it is available in the USA.
8NMB420 - High Output MB Neodymium Driver
I used it (16ohm version) paired at 1.8kHz with a ScanSpeak 6600 and it is VERY good, efficient and of high fidelity.
However I don't know where it is available in the USA.
That 8NMB420 looks pretty good and with the exception of the FS being 20hz higher then the JA8008 the t/s are pretty close
JA8008
Re: 6.0 ohm
Fs: 42 Hz
Vas: 48.3 litre
Qm: 1.74,
Qe:0.28
Qt: 0.24
Sd: 227 cm2.
8NMB420
Fs 61 Hz
Re 5 Ohm
Sd 0,022 sq.mt. (34,1 sq.in.)
Qms 4
Qes 0,31
Qts 0,28
Vas 33 lt. (1,2cuft)
Mms 14,9 gr. (0.033 lb)
BL 10 Tm
Linear Mathematical Xmax (7) ± 5,75 mm (±0,23 in)
Le (1kHz) 0,35 mH
Ref. Efficiency 1W@1m (half space) 95,6dB
In fact I Believe I heard a pair in a friends truck and loved them in that application. The problem is that they are hard to get in the US currently.
I am not sure the higher Fs is an issue if you were to use it in the DTQWT but in the TQWT it may be a bit thin on bass.
JA8008
Re: 6.0 ohm
Fs: 42 Hz
Vas: 48.3 litre
Qm: 1.74,
Qe:0.28
Qt: 0.24
Sd: 227 cm2.
8NMB420
Fs 61 Hz
Re 5 Ohm
Sd 0,022 sq.mt. (34,1 sq.in.)
Qms 4
Qes 0,31
Qts 0,28
Vas 33 lt. (1,2cuft)
Mms 14,9 gr. (0.033 lb)
BL 10 Tm
Linear Mathematical Xmax (7) ± 5,75 mm (±0,23 in)
Le (1kHz) 0,35 mH
Ref. Efficiency 1W@1m (half space) 95,6dB
In fact I Believe I heard a pair in a friends truck and loved them in that application. The problem is that they are hard to get in the US currently.
I am not sure the higher Fs is an issue if you were to use it in the DTQWT but in the TQWT it may be a bit thin on bass.
Sure it's an issue ! Higher Fs with 20Hz more... Have you ever heard a speaker with F3=60Hz (a mini-monitor) and one with F3=40Hz (a floorstander) ?
Would you build a big floorstander with the bass extension of a mini-monitor ?
Fostex is not my favourite manufacturer but the real T/S of the FE206 is much closer than the 18sound. The 18sound is done for Pro (not HiFi) in a 2 ways, a lot of level on the dance-floor, or you can put it in a 3 ways which is more logical.
See this article about the fostex : Fostex FE206E Fullrange Loudspeaker Driver
Note : if Troëls have done a driver, it is for real reason ! it didn't exist.
High efficiency come at a price ... You should consider a driver with less sensitivity 90dB, but more affordable like the CA22RNY. It works well in a classic BR box. Perhaps you can use 2 of then, gives you 96dB/2.83V for the same volume or less than a TQWT.
not wanting to repeat but the CA22RNY (the larger magnet version of the CA22 RNX) is about as close as you can get to the Jantzen without being a Jantzen - it is a solid 92 dB (only a couple of dB off the Jantzen) and less than half the price. It even has the same dip in response at 800 Hz and the same HF roll off. However any driver if it isnt the Jantzen will require a re-design. Is the effort worth the money?
Your right that he built this driver because there wasn't something that fit his needs perfectly. I am sure the driver is one of the best available, that doesn't mean there aren't drivers that come close enough.
The DTQWT has 2 10" drivers to fill in the bottom end, I am not so sure you would really miss the 20hz difference.
No there are not a lot of drivers that come close the JA8008 
The Troëls's TQWT is not the only way if you want high sensitivity speaker, you can go to other solutions
Beyma 15MI100 + B&C DE250 + RCF H100 100dB/1w/1m
Beyma Speakers - Beyma 15MI100 speaker - Beyma 15MI100 700 watt 15" mid-bass speaker for all quality mid-bass applications. Beyma 15MI100 mid-bass and other Beyma 15" speakers here.
B&C DE250 is a 1" high frequency compression driver- B&C DE250 high frequency drivers - B&C 1" high efficiency high frequency driver for speaker systems. B&C DE250 high frequency drivers available now.
RCF H100 1" Horn 90x75 294-802
260+140+90=490$ 1000$ driver per pair
Schematic here : http://francis.audio2.pagesperso-orange.fr/Filtre_Passif_15MI100_DE250.pdf
The Troëls's TQWT is not the only way if you want high sensitivity speaker, you can go to other solutions
Beyma 15MI100 + B&C DE250 + RCF H100 100dB/1w/1m
Beyma Speakers - Beyma 15MI100 speaker - Beyma 15MI100 700 watt 15" mid-bass speaker for all quality mid-bass applications. Beyma 15MI100 mid-bass and other Beyma 15" speakers here.
B&C DE250 is a 1" high frequency compression driver- B&C DE250 high frequency drivers - B&C 1" high efficiency high frequency driver for speaker systems. B&C DE250 high frequency drivers available now.
RCF H100 1" Horn 90x75 294-802
260+140+90=490$ 1000$ driver per pair
Schematic here : http://francis.audio2.pagesperso-orange.fr/Filtre_Passif_15MI100_DE250.pdf
Jerome69, Not to get to far off the subject but I have thought about building a similar design to what you suggest. I would use the autotech OSWG + de250 and either a B&C or Beyma 12BR100. Have you built a setup using those pieces? If so PM me and tell me about it. I would like to know what you thought of it and what you thought of the RCF H100.
Hi DJNUBZ,
I agree with you and Troëls that there is a growing market for a high efficiency, wide bandwidth 8" midbass.
I used the limited JA8008 published data plus the T/S equations to make estimates for the remaining paramenters for the Jantzen JA8008.
JA8008 published data
Re: 6.0 ohm
Fs: 42 Hz
Vas: 48.3 litre
Qm: 1.74,
Qe:0.28
Qt: 0.24
Sd: 227 cm2.
Estimates from T/S equations(anyone have real data?)
Mms: 17.4 g
Cms: 0.0007
no efficiency: 0.0127
Rms: 3.2439
Sensitivity: 93.25 db/watt
Using the Tang Band W8-1808 full range as a starting point, I attached a table with the T/S parameters of an imaginary wide bandwidth 8" that looks attractive to me. The dream would be to get the underhung motor from the ScanSpeak Illuminator 18WU8741T00 with the light cone and rubber suspension from the Tang Band W8-1808. I currently use the (now expensive) W8-1808 with the whizer cone cut off for my midbass with good results in a 3-way.
I agree with you and Troëls that there is a growing market for a high efficiency, wide bandwidth 8" midbass.
I used the limited JA8008 published data plus the T/S equations to make estimates for the remaining paramenters for the Jantzen JA8008.
JA8008 published data
Re: 6.0 ohm
Fs: 42 Hz
Vas: 48.3 litre
Qm: 1.74,
Qe:0.28
Qt: 0.24
Sd: 227 cm2.
Estimates from T/S equations(anyone have real data?)
Mms: 17.4 g
Cms: 0.0007
no efficiency: 0.0127
Rms: 3.2439
Sensitivity: 93.25 db/watt
Using the Tang Band W8-1808 full range as a starting point, I attached a table with the T/S parameters of an imaginary wide bandwidth 8" that looks attractive to me. The dream would be to get the underhung motor from the ScanSpeak Illuminator 18WU8741T00 with the light cone and rubber suspension from the Tang Band W8-1808. I currently use the (now expensive) W8-1808 with the whizer cone cut off for my midbass with good results in a 3-way.
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Any driver contemplated for the TQWT or DTQWT will need a very low qm like Troels driver, otherwise linearity will turn to cr@p in the midrange.
As planet10 has argued - a TQWT design is NOT ideal for a midrange solution (including low midrange).
Extrapolating this information (when considering a different driver) should lead you to the conclusion that a design like the DTQWT is perhaps better served with a dedicated mid that is NOT loaded in a TQWT, which would NOT require similar T/S parameters to Troel's driver. It would be a different design, but perhaps a *better* design.
For instance I could see a similar TQWT for the bass section with a large tube, (8" "sonotube"), bisecting the internal TQWT that "encloses" the midrange - perhaps with an aperiodic opening at the rear. A 6MD38-8 from B&C might work well for this. The slightly smaller mid driver would also allow for closer placement to acoustic center of the mid for the tweeter.
As planet10 has argued - a TQWT design is NOT ideal for a midrange solution (including low midrange).
Extrapolating this information (when considering a different driver) should lead you to the conclusion that a design like the DTQWT is perhaps better served with a dedicated mid that is NOT loaded in a TQWT, which would NOT require similar T/S parameters to Troel's driver. It would be a different design, but perhaps a *better* design.
For instance I could see a similar TQWT for the bass section with a large tube, (8" "sonotube"), bisecting the internal TQWT that "encloses" the midrange - perhaps with an aperiodic opening at the rear. A 6MD38-8 from B&C might work well for this. The slightly smaller mid driver would also allow for closer placement to acoustic center of the mid for the tweeter.
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