Chienmortbb

Just wondering about the benefits of a cast aluminium basket. Fane make a good looking 10" Sovereign 10-300 and a virtually identical Sovereign Pro 10-300 and virtually the only difference is that the slightly more expensive Pro has an aluminium basket rather than pressed steel.

[quote name='owen' timestamp='1408141170' post='2527645'] Anyone know of any decent plate power amps to bolt onto something like this? [/quote]there are very few full range plate amps available commercially. Most are subwoofer amps. Matrix do the GM50 ( http://uk.matrixamplification.com/amplifier-modules.html). Minidsp donthe PWR-ICE125 and 250. The matrix one is a Class AB amp and will get warm. The minidsp one is based on am Icepower Class D amp and will run cooler and also has DSP processing included. That may or may not be useful. I have heard that the Minidsp amps are limited to 6 ohm min when operating in bridge mode. I am trying to verify that at the moment. Evotec (www.amplifier.co.uk) have Class D ones listed but you will have to contact them about purchasing. However, owing to the hest issue, the extra weight and the difficulty in obtaining a good seal, I would not use a plate amp in a Bass Cab.

[quote name='eude' timestamp='1408461220' post='2530414'] I've heard mixed reviews of the 208 Combo, reliability has been and issue with them, but if you look hard enough you can find negative opinions on pretty much everything out there. The early batches of the MiBass 2.0 gear had a bit of a fault, which was easily fixed, but I've been very happy with mine. I think the MiBass would give you the option to expand your rig, if you go for the combo, or the head and cab, you could add another matching cab and get the full output from the head which would give you more than enough power for most occasions. IMHO, a MiBass setup will give you a lot more for your money than a standalone combo like the TC 208. Ultimately though, if you've got a chance to try the gear out, then go do that before you pull the trigger. Hope that helps dude, Eude [/quote]I have played the TC combos and while the 15 sounds OK the 208 has no real sound except a lack of mid bass punch. The 15 is really light but not small.

Any news on the next Bash?

I agree Lawrence. I think this is what Bill was saying. We have to think of the port as a spring, and varying either the lenght or area will alter resistance to the movement of the cone and hence the efficiency of the cabinet. Using ports that are too small will offer more resitance to cone movement and increased chuffing. Flaring the port will reduce the chuffing but will not alter the "spring" of the port. What might make sense is to use the correct port (17-20 m/s) but also add a flares. This will assure that even at full power there will be no turbulence. Unfortunately adding flares will lengthen the port as a whole and I suspect that the current design is tight on space for ports. The other issue is that the response lower down is affected by the overal size of the baffle. This would suggest that the depth be as short as is practical. This reduces the space for a port mounted either on the front or the back. I am learning all the time but is a side mounted port a possibility?

I don't think sound levels are a problem Phil but I wanted to be sure I specify my amp at a level that will do the cabs justice. So judging by your Hartke amp spec 350W into 4R is a good starting point. Incidentally I have the Sound Check 2 disc and meter that you can borrow if it is worthwhile. Details here http://www.canford.co.uk/Products/25-244_SOUNDCHECK-2-TEST-AND-DEMONSTRATION-CD-Alan-Parsons This shows the one without the response analyser but mine has the response analyser included. PM me if interested.

I was thinking that, only launched a Namm this year.

I did say maybe...... I am just wondering about the power requirements and sensitivity. Phil, what is the amp or amps you have been using in testing? My calcs suggest about 250 watts to achieve 120 dB SPL. So would you recommend 250W into 8R for one cab and 500W into 8R? I am going to build my own amp soon and may do a similar build diary.

I think this proves what many of us knew the Ames will go way way down but the very low stuff is not realy good for real world gigging. Alex designs for real world playing good work although it may have been beter if you had made it a blind test.

[quote name='stingrayPete1977' timestamp='1407275826' post='2519172'] Im no expert but as I see it in laymans terms the problem with your calculation is that you are working on the 100 watt amp running flat out, constantly, I suppose if you did that your theory might work until the amp or speakers died but in real world terms how much wattage is an amp putting out during a gig? [/quote] The amp power is not important except, as Bill says, that it can cope with half the impedance (yes I am talking of two identical cabs). The more I think of this, the more I think of other parameters that may affect matters. It there a different effect if the cabs are stacked vertically or side by side. I think I may have to get some cabs out and measure. Don't hold your breath though as the cabs are at the back of a very stacked garage.

It is often said on here that if you have two cabs rather than one it is louder. Is that really the case and if so is it always the case? I am not trying put over a point here it is just that in some ways that statement makes no sense and in some ways it does. Take for instance a Valve/Tube amp running into one cabinet at 8 ohms it is a 100 watt amp running at 100watts. Add second cabinet and switch the impedance switch to 4 ohms and at each cabinet will recieve 50 watts is all else is equal. Added to gether we have twice the speaker size in both driver ans cabinet but the same power, so no extra acoustic output, the SPL is the same. The only difference is that the new cabinet is closer to the player's ear so it will sound louder and have more mids and highs. So that would suggest that only the player will hear a difference. If we do the same trick with a well specified solid state amp it is different. If the SS amp has a meaty power supply, the two speakers would each get 100 watts and there would be a 3dB lift in power and presumably SPL. However in this case we have upped the power as well as adding a speaker cabinet. Be aware that many amps skimp on the power supply and the giveaway is if the 4 ohm output in only a few tens of watts higher than the 8 ohm output rather than double. It may be that speakers get less efficient as you drive them harder ( a stretched surround is harder to pus that a relaxed one) or it could be a reduction in power/thermal compression, some form of maybe the combined size of the two baffles helps with bass response. So my question is are people talking about the second case where there is a corresponding increase in power or is there some acoustical magic that happens when two identical cabinets are used instead of one, even if the power feeding then is the same?

I know Alex at Barefaced used the 3012HO in some of his earlier designs so it is a good speaker, but whether it is worth the extra £100 over the Beyma, I am not sure. I think the Beyma will have the edge The weight is about 1.3kg lower than the Beyma but at under 15Kg, the Beyma loaded cab is no heavyweight and looks favourite to me. Now I will shut up...maybe!

Thanks for that Phil.One more question then I'll leave you three to finish the design. Have you tried any other driver in the cabinet? The reason I ask is that modelling them in WinISD Pro Alpha, the Beyma seems to win on almost every criteria. Will that be the defintive driver? BTW what software is Stevie using for modelling?

There is no reason why a 2x10 should sound better or worse than a 1x15. All drivers and cabinets are different and if your 15 has a similar rsponse on and off axis to the rumble's 2x10 and the same sensitivity, you will be fine. The problem is that no one publishes the figures. Bill Fitsmaurice will probably say I am wrong and if he does he is more than likely right but two wrong 2x10s will sound bad and so will a mixture of cabinets with unmatched drivers. If the two enclosures are identical and had more than a 100 hours or so use, they should work well together.

Again depends on when and where as Exeter is a real trek from Poole,

[quote name='Bill Fitzmaurice' timestamp='1406985707' post='2516449'] They don't. An undersized port can cost you 3dB. By using a flare you can recoup some, if not all, of that loss, but it won't give you 3dB more than a port that's correctly sized to begin with. [/quote]I was paraphrasing the blurb on the Precision Ports site Bill and my worry always was that, as in plumbing, the flow is dictated by the smallest bore in the system. Whilst turbulance may be reduced, the air velocity and c the pressure is still high. So is this treating the sympton rather than the disease?

Ports. Flared ports supposedly give you an extra 3dB so this should mean you could work with an air velocity of 30+ and not suffer the turbulence we hear as chuffing. However there is only so far you can take this as you cannot fight physics. Precision ports would put about £30 on the project price and that seems to to defeat the low cost of the driver. Duke Le Jeune recommends a diagonal 45 degree cut on the inner end of a straight port to give a larger area at the port entrance. This adds one port radius (ie 37.5 mm for a 75mm diameter port) to the length of the por but as the air move both ways, this may not be as effective as the correct sized port. At least with a slot port you only have one large round hole to cut.

I have just reread the thread about 3 times and apart from realising what a pompous ass I sound, it has been very informative. Firstly the Beyma SM212 driver. I don't know how I missed this driver when searching before but it is a gem, it models really well and I am struggling not to order one now. I will wait until the end of the project though. Secondly, the choice of 12mm Ply for the cab. This clearly means more work for the three musketeers, but will end up with us all learning more. As the concept is that you can get your wood cut at B & Q, can you confirm what plywood you are using? The standard stuff at B&Q is a fairly medium grade Exterior Ply although they do do Birch and Spruce in 19mm thicknesses only. My first PA speakers were built by my Dad from 12 MM exterior play and properly braced they are great. Also what wood adhesive? On the prototype cabs there are a lot of screws around the baffle. The fearful build are screwless, relying on the strength of the adhesive. Why so many screws? Will the design be screwless or is that not part of the design criteria? Hmm just rethoughtthis and realised that you have to have full acces to the interior to play about with bracing.

I have to agree that 3012 might improve matters but I feel the whole cabinet could be compromised. They look good and you like the sound so stay with that for now. Without a lot of work you will not get the results you required and could spoil the cabinets.

[quote name='mcnach' timestamp='1403294807' post='2481664'] it's definitely a bit of both, when it comes to onstage volume. I have used two cabs onstage live many times now, not so much because I need the volume (I'm DI'd most times, and onstage two cabs is unnecessary), but because the stack is higher and I can hear it better using probably less volume overall. It seems a bit wasteful, but the cabs take up so little space and are so portable, so why not? [/quote]Perhaps Barefaced should add dummy cabs to the range as cabinet stands. I am not sure wheterI am joking or not!

[quote name='charic' timestamp='1406621298' post='2512987'] Chien, if you're trying to post up the results using HTML you're onto a losing battle against the software I'm afraid Tables don't work in these 'ere parts [/quote] Ha Ha I have just found that out. I will convert to a jpg and post them later.

I bought a Hornet Bass 45 for a practice amp. Would pulverise many 100 watt combos I have played.

[quote name='Bill Fitzmaurice' timestamp='1389204252' post='2331349'] It can make the crossover appear as a dead short. Read this: [url="http://www.bcae1.com/xoorder.htm"]http://www.bcae1.com/xoorder.htm[/url] An Lpad will only work as it should with a resistive load, piezos are a capacitive load. To use a piezo with either an LPad or a crossover additional components are required. [/quote] There is much myth and mystery about Piezos and you have to blame Motorola for poor marketing. Piezo tweeters work better and are protected by the series resitor but it does nothing to succesfully integrate a piezo tweeter into a speaker system. For proper balance between the tweeter and the other drivers, it has to have a proper crossover. Then you get a smooth response that will outperform compression drivers. One thing to be aware of though is that if MB only use the dreaded series resistor, then just replacing the piezo with a traditional magnetic tweeter will result in speaker failure eventually and not give a very good performance untill then. Do you have picture of the tweeter? What make and model is it?

[quote name='martthebass' timestamp='1406129814' post='2508630'] Funny you mention that I've had a Behringer mic for years and it outclasses the SM58 for clarity........still use mine in preference to one. [/quote]I read that many BBC soundmen carry Behringer mics as they sound better than SoMe others.

OK I have modelled the two Kappalites and there is no doubt that the box you are using is far from ideal for the Kappalite 3015LF. Your box is less that 50 litres internally and that is ideal for the 12" but the 15" prefers a much bigger box. As is you probably have a small peak at about 100 -120Hz an a steady roll off from sbout 90. In the same cabinet, and with the right porting the same cabinet cold give an extra 6dB around the 40-60Hz area, the area that the Acme's are strong. Ironically the current thread would probably give you better results than the cab/speaker combination you have. On the plus side, the cabinet you have is small, neat and if it works for you, keep it. I don't think you could install a 12 in this cab without major surgery and I am not sure where you would put the ports. Are there any ports on the back?