Timpano TPT-SP4BT Bluetooth DSP 4 Output Channel- Full Digital Signal DSP Car Audio Processor - Built-in Voltmeter and Remote Relay

I bought the Timpano DSP mostly as a limiter because I was not satisfied with a competing product. The Timpano has a lower input noise and wider dynamic range. It should do a great job for most applications if you understand how it works. Adjusting it is not really for beginners, so for those new to this please keep an open mind that you may discover things you didn't know and may need to seek out an expert or do some research. You need some supporting tools to do this and even with tools, expect to take some time to optimize things. You don't want to "wing" it or tune by ear or you won't get everything that your system is capable of and you could waste a lot of time.Before going through the tuning process here are some important features of the Timpano:Low costLight plastic case with simple 2-fastener mounting.Low profile and small sizeFree Bluetooth app which worked perfectly with my Samsung Android phoneThe RCA inputs are semi-floating, low noise, differential inputs (nice!)The "high" or Spr input is also differential and attenuated by 20dB and has a 1K impedance.Up to 15dB gainLimiter threshold is based on signal's 1/2-wave rectified average value, referenced to the full output.Full output (0dB) is about 5.6vpp or +8dB VU.There was a gradual drop in output above 12KHz but this can be managed with the EQ.Power supply rejection is as good as most other equipment but be sure to feed it clean power.The "auto" settting of the limter is 100mS attack and "1600mS" release - but please see below.The EQ is applied at the input and affects all outputsThere are separate adjustable parametric filters for the individual ouputs, before the limiter.The unit's best feature is the low noise differential input which the mfr does not mention. All gear with RCA inputs should be made this way. This design breaks any ground loop on the input, making it easier to interconnect this with other devices without having ground currents flow and picking up noise in the process. This makes the unit perform well even with the plastic case. I found no extra noise resulting from the unshielded case. I'm not sure I would use this device for recording just in principle, but the noise figures look great actually.Setting the maximum input level reaching the Timpano is important because the Timpano inputs clip at around 5.6vpp or +8dB. Some gear powered by 120V can generate an output significantly greater. I have a mixer/preamp which generates more than +18dB which would be a huge overload. In order for things to interoperate properly, I built a -11dB resistive divider to permit the full output from my preamp to be fed to the Timpano. To offset this the 15dB of internal gain on the Timpano was needed. The noise performance was impacted slightly but was still completely acceptable.Some customers mentioned the flimsy RCA jacks. At this price I'm not concerned but be smart. I would not under any circumstance plug a "monster" cable into this. Monster cables are for looks only, waste money, and damage fragile jacks. Use only soft, thin RCA cables whose connectors are neither loose or tight. You don't need to spend a lot of money on RCA cables.The power terminals are well-made if you treat them properly with wire that is not stiff and you do not overtorque the terminals. They are recessed and have square washers for a secure fit. They depend on the circuit board for support so don't abuse them.My only "complaint" is the release time of the limiter is shorter than advertised. The "attack" time works properly at up to 100mS. The release time is actually about 1/4 of the advertised 1600mS or 400mS. The limiter lamps don't turn off until about 1200mS but by then the audible effects of the release have long decayed. 400mS is a short release time and will give a pumping effect if the limiter is hard-driven on music with a pulsing bassline. For "normal" use the decay is OK but there isn't extra room to adjust it. It should be advertised as a smaller number.The limiter threshold tends to work a little differently on devices from different manufacturers. This is not a peak limiter or RMS limiter, but approximately a half-wave averaging limiter and the threshold needs to be adjusted based on that. A threshold of around -18dB (1/2-wave rectified, averaged, with respect to the peak output) is good. This allows a sin wave to generate a peak VU output of around -6dB. With this setting, music or white noise will peak at about +3dB VU. The Timpano output clips at about +8dB VU so there is still 5dB headroom within the limiter and the musical output can remain unclipped or nearly so, depending on the musical attack. I would not recommend increasing the threshold above -13dB or music may be clipped if you drive the system hard.The above paragraph gives hints on how your amp should be adjusted. I would suggest a VU meter that handles the full amp output. Wear hearing protection and play a sin wave and increase the amp gain until clipping, then back off by 6dB. Final adjustment would be with your ears, being careful if you need protection. With the limiter driven hard, increase the amp gain until you can just hear the distortion, then back it off until you can't.With this setting the amp will still be clipping slightly on the attacks which are already exaggerated by the 100mS response of the "auto" setting on the limiter. The effect of the exaggerated attacks will be offset by them being clipped and the result is the effects largely cancel. This is the loudest your amp could play and sound fairly clean using the limiter's "auto" setting. It should be slightly "fatter" and clearer than what you get without the limiter and should have no distortion "crunch" unless that's what you tuned for. You should also be able to increase your input volume all the way and it will not get louder or sound much different.I haven't even mentioned the EQ. An inexpensive but amazing RTA tool was used for tuning the EQ. I used a Dayton Audio iMM-6 (older generation) calibrated mic with Bofinit "Audiotool" app installed on an old unused Android phone. I also used a white noise test file. Full volume is not required so save your ears and play the white noise at medium volume without the limiter kicking in. After calibrating the mic by downloading and installing the Dayton Audio calibration file, play the white noise and record the speaker's profile with the audiotool RTA app at full resolution. My speakers were EV SX100+ and the profile I recorded using the RTA matched the engineering data sheet from the mfr almost exactly. I made two tweaks, using the parametric EQ to tame down a ringing of the tweeters at 18K, and using the graphic EQ to push down the response at around 6K. The speakers sound smoother and I'm very satisfied with the DSP doing its job.The additional tools I used for tuning were absolutely necessary but not expensive. I used an old PC with embedded line in and out jacks. The software was Cool edit 96, Audacity, and VLC media player. I also needed a peak VU meter which was the most expensive tool. A cheap AC voltmeter can work instead of the VU but skills are needed to understand the reading. If it's an averaging or true RMS meter the reading will continue to increase even during clipping and the results can be misleading. Resistors were needed to give the VU meter enough range to handle the maximum voltage from the power amp, making the peak output fall into the middle of the VU meter range. Resistors were also needed to level shift between my preamp and the Timpano.To sum up, a limiter should be used to complete just about any audio system big or small. To me the graphic EQ of this product is just a free bonus. Together these features make the Timpano a great product. If adjusted properly you will be able to hear the difference and your system will be more forgiving and enjoyable.

They layout once you download the app is very easy and effective, I'm very impressed with sound and the functions for cost. Been an audio enthusiast for 30 years ! Love the sound generator and sweep function to really see how your subs dig. Worth every penny !!!

At first when installing I am like WHY WONT THIS POS connect....... Then I realized the instructions aren't 100% correct. The unit was booting up so fast that it was already showing up in the app. I thought the line where the device is shown was just saying what it was expecting to find and then I would see the Bluetooth ID under that. Nope that IS the device, so just click right on that spot.You can 1 time copy settings between channels which is good for initial setup but if you have and want stereo sound going to your amp then you will need to manually copy the settings each time or use the copy button each time which is in a completely different section.It sucks when tweaking settings and say you're trying to find where you want that extra punch in the EQ and how much Q to apply, you can either unplug one RCA or change all the settings, go into the other channel and do again and back and forth.The High input is a total bummer and looks like sht in a nice install but the cheap box kind of does in general. The RCA inputs are ultra sketch when using higher end RCA's that really grip the jacks, I feel like I am going to tear then out of the board when plugging and unplugging them, thankfully that's not often. I would have paid $50 more for a better housing and Allen screw high inputs.Something like any $50-$100 crossover on the market, I know this does more than that, but I am saying if a $50 crossover can have a nice housing and better inputs then it must not cost that much, and I would have gladly paid $50 more.Overall, for the money and if you don't already have a DSP on your subs or anything you have an AMP for, well simply put... that's dumb. Its LOUDER and CLEANER period, don't care how good your head unit or amps are, without a DSP you are missing out big time,

This is really the only product of its kind, as far as I can tell. Was looking for a simple stereo DSP to use inside a classic jukebox for volume and EQ. But this unit is four channel, which is fine. All audio adjustments are made through an iPhone app, which is very nice for a jukebox, as most of those controls were originally internal and not easy to access. Sound quality is good, and the unit is fairly intuitive to setup and use. One quirk with the software, however: You have to use the app’s “connect” button to establish a Bluetooth connection. Trying to do it with your phone causes it to fail. Other than that minor annoyance, it’s a good product that I would get again.