Is TQWL confirmed

Leave the archive and display this page in the standard design: SP-8/4 Mini-TQWT


I'm currently working on a mini-TQWT as a by-product. The starting point was that I had bought a Pollin mini stereo amplifier with SD slot and FB for professional purposes and was looking for a pair of small Breitis in 4 ohms that could harmonize with it.
When I was about to order a pair, it occurred to me that I still have these little Monacor 'beasts' in my stock. TSP measured and a small TQWT simulated despite a Qts of almost 1.0.
Just measured on the axis and fumbled a trap circle:

As always; heard no sound yet. Let's see if you can listen to music with it. Expectations are not very high, as the box including wood and locking circle costs around 15 euros.

LG Gazza

Hi Tom,

yes, that's okay ...
With a blocking circle, the value increases enormously ...
I read with great interest :)

Hi Tom,

looks interesting...

You can also listen to the whole thing without a blocking circle. That could sound like it. Thomas can confirm that. He also modified his box with the chassis (after my attempt: D). I think that's okay in terms of sound.

When you finally have the housing clear, I would be interested in it too. I also have the Pollin part ...

Hi Tom :)
Funny little project. I'm curious how it turns out: D.



I'm currently gluing the second box and listening to mono.
With that one seems to be able to listen to music seriously; there is even some bass. The King Simu suggests that below 80hz not too much is coming.

Still, a little grin on my face: D: D

Here are the key data of the Simu. In the end it was a trade-off between linearity and exaggeration in the bass. In the end I just built, because even small changes in the Simu can move something and you can't build that precisely, there are tolerances in the chassis, etc. (As our Hoschi always says: "I build loudspeakers, not a moon rocket"!)

I didn't have the tenors on my screen, but had looked more closely at Thomas' / Günther's box. Thomas had also signaled to me that the speaker was worth a try, despite the high Qts. Thanks for that!! Seems to be confirmed.

It's all too early, but the small boxes can do more than I would have thought: dance :.

I will continue to report. LG


Since I hadn't heard the box without a blocking circle at all, but had knitted the blocking circle directly after the first measurement, I wanted to hear after Günther's advice whether it would work without it.

My first conclusion is: go; but there are limitations in my eyes. For example, when setting up on a table, I would recommend the blocking circle; free it is also quite ok without it. In general, however, voices with a blocking circle sound more natural, and the overall sound is clearer.

It would certainly be presumptuous to speak of audiophile qualities in the project (after all, everything is at the price level of PC loudspeakers) but I listen to music very pleasantly when it is set up freely with a blocking circle.

Pictures / measurements follow, just wanted to report the 'water level'.

LG Gazza

P.S .: Lock-out circuit is L 0.47mH (0.57 Ohm) / C 22mF / R 3.3 Ohm
(all cheap components; a total of just under five euros)


I played around a bit earlier and looked to see if something could be done on the FG (superelevation at 3khz).

This is possible (on axis 1m):

Suction circuit off: L 0.56mH / C 5.6mF / R 3.9 Ohm

It's just a gimmick, of course, because at some point the point will be reached where I can get a higher quality driver right away. Still very funny: D
Maybe there is also some cheap 'dirty spool' with high resistance and a cheap condi !?

Also take pictures of the box, but the moment is also kicked off :)

LG Gazza

Hi Gazza
Interesting, I have the amp in my sights right now and with the SP 8-4 I have just built my own tenor (coming soon in this th ...).
Can you post dimensions and FG.



here are two pictures to show the dimensions and 'inner values':

The box doesn't have to be standing; I see an opportunity to play something, especially when I am standing on a table. I designed the port like this because it is difficult to do otherwise at this point in the line and costs nothing with a small wooden strip inside.
I stopped tinkering with the FG (see above). Heard and measured, it fits. So total beer bottle height (0.5): D and 12cm depth; Attenuation was taken from leftovers; The inside of the baffle cutout is slightly enlarged with a rasp so that the small speaker can 'breathe'.

I'll hear the speakers on the Pollin Amp afterwards. The finish should be cheap in the style of the box. I already have an old newspaper from Liverpool lying here and will approach it like Der Hobbyler. If I can still find a cheap coil, I will think about using the suction circuit as well (this is clearly noticeable in the FG and also brings a little more 'clarity'; but this is a luxury for this project).

After a little listening, I would confirm that, in principle, you can do it without any correction if you set it up freely, but that it sounds much more cultivated with a blocking circle.

So in the end:
- the student variant (without corrective measures) for 10-12 euros (somewhat dependent on the price of the speaker, I could buy it for around 7 euros at the time)
- the 'cultivated' variant (with blocking circle) for slightly higher demands; around 15 euros
- the 'almost audiophile' variant (with blocking circuit and suction circuit for the superelevation at 3khz) for about 20 euros

each of the drivers, technology, and wood.

LG Gazza


I've just come from the basement and heard the latest MB mixed tape with the Pollin amplifier and the mini TQWT. It's fun and more than loud enough for a room volume.

According to the information on the packaging, the amplifier delivers 2 x 10W into 8 ohms; the box with the Sperkreis is between approx. 5 and 7 ohms. Now 2x10W doesn't sound very much, for the purposes that is absolutely sufficient in my opinion.

Since I had set out to tinker with the mini-amplifier 'something that sounds small', the project is a success for me. It sounds very neat and I only used material that I already had in my fund (excluding the 5 euros for the wood). The SP-8/4 is more than ok, I'm glad I didn't buy anything new: D.

In my opinion, you can hear a lot of music with this:
(Matchbox to compare the size of the amp) / I think the remote control is very practical, it could react a little more directly.

Now I'm wondering how to screw things together !? Actually, I want to screw the mini-amp onto the case; small cover over it, done. There are these 'strange' screws (spacers with thread, etc. to screw the circuit board onto a sheet of metal, for example); where do you buy such small parts or what is the technical name so that I can search accordingly?

LG Gazza

P.S .: I want to round off the edges of the case with a milling cutter so that it looks a little more homely. Acoustically that should be ok, there is not much material for milling with 12 mm MDF anyway.

Hi Tom,

nice little project that I will probably build myself one day. I also have the amplifier and a pair of chassis lying around.

It would be great if you could post the final housing dimensions including dividers again. That would make the replica even easier ...: D

In any case, this is an alternative to the tenors. Thank you very much: thank you :: cheers:

Spacers are available in computer accessories. With this, e.g. mainboards are mounted in the case ...;)


@SonicSL: Thank you; that's exactly what I'm looking for.

@ Günther: Here is an attempt at a 'construction plan'; is more of an illustrated guide:

Wood cutting:

Place a side wall on the workbench, then glue on the cover, front and rear wall and the bottom; Make the baffle cutout and port beforehand.

Then glue the divider according to the following dimensions:

Then glue the port:

Dimensions for the baffle as follows:
(Cutout for the driver 7.3cm diameter)
Danger!!! When assembling the second box, the cutouts would have to be made in mirror image due to the off-center speaker and the port / is actually clear, but I had almost started the saw myself when the circumstance occurred to me

Of course, apply damping as described before gluing on the second side wall. I would do the same with cabling, connections, etc.

I'll see if I take more measurements later, but for the project I want to leave the church in the village. The later line-up might have more influence. The little ones make me happy at the moment. I would be happy if somebody might copy it.

LG Gazza

Hi be

another question about the divider:
Up is 4.2cm and after
right ??? cm (or to the left)

So long


I think he means the distance back wall> divider above. The rest comes from the cut.

I think they're really cute. I like such small, cheap projects. You can certainly listen to it great. : thumbup:

Where are the components in the housing?


Where are the components in the housing?

Will be actiiihiiiv ...: cool:

Nope, only active insofar as the amp hangs on a box. The equalization is passive ...: eek :: rtfm :: D

I read about the divider like Olli ...


@Mat: is thought of as Olli says, the divider has to the rear wall (actually the front, but the speaker is in the second part of the line) distance T1 = 2.5cm and T2 = 4.2cm; The distance upwards and to the baffle is then automatically obtained.

@ Olli / SonicSL: I actually wanted to screw / glue in the few small components at the end of the line; In fact, that's not factored in, but it shouldn't do that much; But it would be difficult to get back to it if something happened. For these reasons it could also simply be outside.

These are questions of detail that I still have to deal with. I didn't think these things would work so well myself. As I write this, I tend to screw the components with the amplifier onto the back. Or unscrewable side wall? (With 12 mm MDF there isn't much 'feed'.)

LG Gazza

Just like Alex at SipPo, make a compartment below where the circuit board comes in ...


have now pondered a bit and have come to the conclusion that I put everything outside. Without a removable side cover, the small blocking circle can just be safely placed in the insulation through the speaker opening; otherwise there is little space in the small box or, due to the divider, little leeway. But since I want to treat myself to the suction circuit for fun and maybe still want to play with the tuning, the technology remains outside for the time being.

SonicSL is right; small compartment for circuit board, if the box is to be operated with such a mini amplifier, it would be very good.

LG Gazza

The compartment on the underside offers space for electronics AND crossover ...


regardless of where with all the 'tussle', I've invested some more time. (I would probably put the simple blocking circle in the damping material or glue it in the broad part of the line beforehand; switch compartment for all electronics makes sense depending on the complexity of the switch.

Earlier I soldered the recommended Sperkreis; (Here's the picture; everyone knows that from you old hands (hear you scream: "Laaaaaaangweilig!"), but maybe beginners will read along who feel encouraged when they see that such a minimal switch is not rocket science !?) :

I also put together the suction circuit for the superelevation at 3khz. While rummaging through my components, I came across these:

Some time ago I also ordered from Pollin or Reichelt; only cost a few cents. Together with a cheap coil and a small 5W resistor, I used it to create another suction circuit that sucks something away at around 8.5khz and costs less than 2 euros in total. Clear; Drivers 8-9 euros, components 11 euros doesn't always make sense; but it's also about 'sport': D;). (@Alex: Thanks for the hint / encouragement.)

Measured it looks like this:

Associated impedance curve:

The impedance drops briefly to 3Ohm at 9khz. I think this is not critical! ??

Heard it looks very neat. Voices and instruments come out very cleanly and clearly, nothing is annoying; nice cheap fun box!

LG Gazza

Hi Gazza

I think your description of the barrier circles is good.
It will certainly take away the fear of one or the other ...

Because it fits the chassis, but is at home in the parallel world, I posted my "little ones" there, tenors.
Have a look here ... (

From now on we should always plan some space for speaker circles and small amplifiers. :)


Hi Wolfgang,

I had the mini TQWT with Alex last Wednesday. They could even play bass pretty well in Alex's room; the space is also extreme in this regard. I had the turnouts externally on two boards: rolleyes :.

From now on we should always plan some space for speaker circles and small amplifiers. :)You said it!!! I plan to fold the Mini-TQWt again asymmetrically, so that a small switch compartment is created, as you have it with your interesting folding.

I also like your 'little ones' optically very much. Wood is more expensive, but the finish is 'included' as a result :). Good idea!: Thumbup:

LG Gazza


the TQWT with the small universal driver from Monacor had to wait a long time for its finish.

In the end, the wiring turns out to be a bit more economical than originally intended in order to take into account the price of the chassis.

The complete documentation can be found on my website (; a short description on the DAU page ( with a link.

LG Gazza

I'm glad you did something with little Monaco too!
I liked it years ago in the box ( and as a 'horn replacement' it is definitely worth a try

I'd be interested in a comparison between box, tenors (original and ML-TML / BR) and the mini-TQWT: D

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