Your speakers, simply put, are NOT tube friendly. 87db just doesn't cut it. If you want some strong, tight bass at reasonable volumes, you should consider at least 90db speakers if not more.
Your EL34 amp is probably 40 watts. To drive your speakers to 90db takes double the wattage. This really adds up:
1 watt = 87db
2 watts = 90db
4 watts = 93db
Your 40 watt amp on 87db speakers will net you approximately 103db. If you had a pair of 94db speakers, the same amps would produce approximately 110db. Rule of thumb is you double your "perceived" volume for every 10db increase.
Also, keep in mind that bass uses the bulk of the power. So, if bass is an issue, you should be looking at something like 100watt amps.
Your EL34 amp is probably 40 watts. To drive your speakers to 90db takes double the wattage. This really adds up:
1 watt = 87db
2 watts = 90db
4 watts = 93db
Your 40 watt amp on 87db speakers will net you approximately 103db. If you had a pair of 94db speakers, the same amps would produce approximately 110db. Rule of thumb is you double your "perceived" volume for every 10db increase.
Also, keep in mind that bass uses the bulk of the power. So, if bass is an issue, you should be looking at something like 100watt amps.